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Association of Chiropractic Care With Receiving an Opioid Prescription for Noncancer Spinal Pain Within a Canadian Community Health Center: A Mixed Methods Analysis

Open AccessPublished:August 23, 2022DOI:https://doi.org/10.1016/j.jmpt.2022.06.009

      Abstract

      Objective

      The purpose of this study was to examine the association between receipt of chiropractic services and initiating a prescription for opioids among adult patients with noncancer spinal pain in a Canadian community health center.

      Methods

      In this sequential explanatory mixed methods analysis, we conducted a retrospective study of 945 patient records (January 2014 to December 2020) and completed interviews with 14 patients and 9 general practitioners. We used Cox proportional hazards regression analyses, adjusted for patient demographics, comorbidities, visit frequency, and calendar year to evaluate the association between receipt of chiropractic care and time to first opioid prescription up to 1 year after presentation. Qualitative data were analyzed thematically and integrated with our quantitative findings.

      Results

      There were 24% of patients (227 of 945) with noncancer spinal pain who received a prescription for opioids. The risk of initiating a prescription for opioids at 1 year after presentation was 52% lower in chiropractic recipients vs nonrecipients (hazard ratio [HR], 0.48; 99% confidence interval [CI], 0.29-0.77) and 71% lower in patients who received chiropractic services within 30 days of their index visit (HR, 0.29; 99% CI, 0.13-0.68). Patients whose index visit date was in a more recent calendar year were also less likely to receive opioids (HR, 0.86; 99% CI, 0.76-0.97). Interviews suggested that self-efficacy, access to chiropractic services, opioid stigma, and treatment impact were influencing factors.

      Conclusion

      Patients with noncancer spinal pain who received chiropractic care were less likely to obtain a prescription for opioids than patients who did not receive chiropractic care.

      Key Indexing Terms

      Introduction

      Opioid medications are commonly prescribed in North America to relieve musculoskeletal (MSK) pain and improve function.

      International Narcotics Control Board. Narcotic drugs 2019: estimated world requirements for 2020. Available at:https://www.incb.org/documents/Narcotic-Drugs/Technical-Publications/2019/Narcotic_Drugs_Technical_Publication_2019_web.pdf. Accessed January 31, 2022.

      However, opioids provide only modest benefits
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      and are associated with important harms, including addiction, overdose, and death.

      Gomes T, Greaves S, Martins D, et al. Latest trends in opioid-related deaths in Ontario: 1991 to 2015. Available at:https://odprn.ca/wp-content/uploads/2017/04/ODPRN-Report_Latest-trends-in-opioid-related-deaths.pdf. Accessed January 31, 2022.

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      There were 24626 opioid-related deaths and 27604 opioid-related hospitalizations in Canada between January 2016 and June 2021.

      Public Health Agency of Canada. Apparent opioid and stimulant toxicity deaths: surveillance of opioid- and stimulant-related harms in Canada (January 2016 to June 2021). Available at:https://health-infobase.canada.ca/src/doc/SRHD/Update_Deaths_2022-06.pdf. Accessed January 31, 2022.

      In the United States (US), there were approximately 60000 opioid-related deaths in 2016 alone.
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      Young adult men have been most affected by the opioid crisis,

      Public Health Agency of Canada. Apparent opioid and stimulant toxicity deaths: surveillance of opioid- and stimulant-related harms in Canada (January 2016 to June 2021). Available at:https://health-infobase.canada.ca/src/doc/SRHD/Update_Deaths_2022-06.pdf. Accessed January 31, 2022.

      ,
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      which has arisen partly among individuals who were initially prescribed opioids for back pain or some other MSK condition.
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      Canadian Chiropractic Association. A better approach to pain management: responding to Canada's opioid crisis. Available at:https://36febd2e085i4aafwh1r32m2-wpengine.netdna-ssl.com/wp-content/uploads/2016/11/A-Better-Approach-to-Pain-Management-in-Canada3-1.pdf. Accessed January 31, 2022.

      Recent reports from Canada and the US indicate that opioid-related deaths have increased during the COVID-19 pandemic.

      Public Health Agency of Canada. Apparent opioid and stimulant toxicity deaths: surveillance of opioid- and stimulant-related harms in Canada (January 2016 to June 2021). Available at:https://health-infobase.canada.ca/src/doc/SRHD/Update_Deaths_2022-06.pdf. Accessed January 31, 2022.

      ,
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      Some chiropractors have called on governments, policymakers, and insurers to improve support for nonopioid approaches for managing MSK-related pain, including noncancer back and neck pain, particularly in vulnerable or marginalized populations.

      Canadian Chiropractic Association. A better approach to pain management: responding to Canada's opioid crisis. Available at:https://36febd2e085i4aafwh1r32m2-wpengine.netdna-ssl.com/wp-content/uploads/2016/11/A-Better-Approach-to-Pain-Management-in-Canada3-1.pdf. Accessed January 31, 2022.

      In 2017, we conducted a pilot project evaluating a newly integrated chiropractic spine pain program at Langs Community Health Center (CHC) in Ontario, Canada,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
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      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.

      Langs. Cambridge: Langs Community Health Centre. Available at: https://www.langs.org. Accessed January 31, 2022.

      Community Health Centres. Toronto: Ontario Ministry of Health and Long-Term Care; 2021. Available at:https://www.ontario.ca/page/community-health-centres. Accessed January 31, 2022.

      and found that 82% of patients who received chiropractic care reported a significant reduction in the use of analgesics.
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.
      ,
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      Chiropractic integration within a community health centre: a cost description and partial analysis of cost-utility from the perspective of the institution.
      However, similar to research on chiropractic integration within other Canadian primary care centers,
      • Garner MJ
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      • Keenan D
      • Manga P.
      Chiropractic care of musculoskeletal disorders in a unique population within Canadian community health centers.
      • Mior S
      • Gamble B
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      • Côté E.
      Changes in primary care physician's management of low back pain in a model of interprofessional collaborative care: an uncontrolled before-after study.
      • Passmore SR
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      • Olin G.
      Initial integration of chiropractic services into a provincially funded inner city community health centre: a program description.

      Centre for Effective Practice. Primary care low back pain pilot evaluation: final report. Toronto: Centre for Effective Practice; 2017.

      • Manansala C
      • Passmore S
      • Pohlman K
      • Toth A
      • Olin G.
      Change in young people's spine pain following chiropractic care at a publicly funded healthcare facility in Canada.
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      our study was limited by the absence of a comparison group.
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.
      ,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF.
      Chiropractic integration within a community health centre: a cost description and partial analysis of cost-utility from the perspective of the institution.
      Moreover, although several uncontrolled studies reported an association between reduced use of opioids and receipt of chiropractic care in various US populations,
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
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      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      comparative assessments of the integration of chiropractic services into primary care settings are sparse.
      • Goertz CM
      • Long CR
      • Vining RD
      • Pohlman KA
      • Walter J
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      Effect of usual medical care plus chiropractic care vs usual medical care alone on pain and disability among US service members with low back pain: a comparative effectiveness clinical trial.
      ,
      • Prater C
      • Tepe M
      • Battaglia P.
      Integrating a multidisciplinary pain team and chiropractic care in a community health center: an observational study of managing chronic spinal pain.
      In addition, the impact and understanding of such integration on prescription opioid use in noncancer MSK pain management remain uncertain.
      To address these knowledge gaps, we undertook a mixed methods analysis to examine the association between receipt of chiropractic services and opioid prescriptions among adult patients with noncancer spinal pain in a primary care setting. We hypothesized that chiropractic care would be inversely associated with receipt of opioids. Further, we hypothesized that younger age, male sex, presenting with comorbid depression, anxiety, fibromyalgia, diabetes or cardiovascular disease, obesity, positive smoking status, a higher frequency of health care provider visits, and earlier years of our 7-year study timeframe would be positively associated with opioid receipt.
      • Emary PC
      • Oremus M
      • Mbuagbaw L
      • Busse JW.
      Association of chiropractic integration in an Ontario community health centre with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol.

      Methods

      Reporting

      We reported our study in accordance with the Good Reporting of A Mixed Methods Study guidelines (see Supplementary File 1).
      • O'Cathain A
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      A methodological review of mixed methods research in palliative and end-of-life care (2014-2019).

      Study Design

      We used a sequential explanatory mixed methods design, where follow-up qualitative data were collected to clarify and explain the quantitative findings.
      • Creswell JW
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      Designing and Conducting Mixed Methods Research.
      This was also the second of 2 analyses undertaken in which these qualitative data were used.
      • Emary PC
      • Oremus M
      • Mbuagbaw L
      • Busse JW.
      Association of chiropractic integration in an Ontario community health centre with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol.
      Our rationale for using a mixed methods approach was that of complementarity
      • Greene JC
      • Caracelli VJ
      • Graham WF.
      Toward a conceptual framework for mixed-method evaluation designs.
      ; that is, the interview component of our study allowed for a richer understanding of whether chiropractic services were used by patients and general medical physicians/nurse practitioners (GPs/NPs) to reduce reliance on opioids. See Figure 1 for an illustrative diagram outlining our study procedures.
      Fig 1
      Fig 1Study diagram of an explanatory sequential design of a mixed methods study on the association of chiropractic integration with prescription of opioids for noncancer spinal pain at Langs Community Health Center. The quantitative and qualitative data collection and analysis phases are shown along the left side of the diagram. The 2 points of interface (or mixing) of the quantitative and qualitative phases occur in the third and final steps. The term “QUANTITATIVE” is capitalized to indicate prioritization of the quantitative phase in the study. The study procedures and outputs for each phase are listed along the right side of the diagram.

      Ethics

      The Hamilton Integrated Research Ethics Board at McMaster University approved our study (project number 2021-10930). Written informed consent was obtained from all participants, and all methods were conducted in accordance with the Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans (TCPS 2: 2020).

      Quantitative Phase

      Sampling

      We conducted a retrospective chart review
      • Vassar M
      • Holzmann M.
      The retrospective chart review: important methodological considerations.
      of electronic medical records (EMRs) at Langs CHC for all adult patients (aged ≥18 years) with 2 or more visits relating to a diagnosis of back or neck pain not associated with cancer between January 1, 2014, (the inaugural date of the CHC's chiropractic program
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.
      ) and December 31, 2020. Patients with contraindications to chiropractic treatment, including fractures, infections, inflammatory arthritis, or cauda equina syndrome, were excluded from analysis. Because our exposure of interest was the addition of chiropractic care to ongoing GP/NP care, compared with ongoing GP/NP care alone,
      • Emary PC
      • Oremus M
      • Mbuagbaw L
      • Busse JW.
      Association of chiropractic integration in an Ontario community health centre with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol.
      we defined recipients of chiropractic care as any patient who received at least 1 appointment for GP/NP care and at least 1 appointment for chiropractic care during the 7-year study period. To be eligible to receive chiropractic services at the CHC, patients had to be referred by their GP/NP; thus, every patient receiving chiropractic care also received ongoing GP/NP care.
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.
      To account for immortal time bias,
      • Yadav K
      • Lewis RJ.
      Immortal time bias in observational studies.
      we retained patients with opioid prescriptions after the index visit but before the first chiropractic visit in the recipient cohort.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      This accounted for patients who were prescribed opioids before having a chance to receive chiropractic care. We only used first chiropractic visit as a recipient inclusion criterion in these cases.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      We defined nonrecipients as those who received 2 or more appointments of GP/NP care alone. GP/NP care included assessment, prescription medication, and referral for diagnostic testing, specialist consultation, or other cointerventions (ie, nursing, dietetics, social work, or physical therapy) at the CHC. Details of the chiropractic program and our list of diagnostic codes are described elsewhere.
      • Emary PC
      • Oremus M
      • Mbuagbaw L
      • Busse JW.
      Association of chiropractic integration in an Ontario community health centre with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol.

      Data Collection

      Our main outcome variable was time to first opioid prescription, and all patients who had not received a prescription for opioids at their last follow-up were censored. An independent information technology specialist who was blinded to our research questions
      • Vassar M
      • Holzmann M.
      The retrospective chart review: important methodological considerations.
      extracted all patient data, including visit and opioid prescription dates, directly from the EMR. Only opioid prescription data between the time of the index and last visit dates for a noncancer spinal pain diagnosis were included. However, it remains possible that opioids were prescribed for other indications, which would attenuate the association between chiropractic care and opioid receipt.
      • Choi BC
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      To increase confidence in our findings, we defined our regression model a priori and selected 12 variables from the EMR database that, based on previous literature,
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      ,
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      A biopsychosocial profile of adult Canadians with and without chronic back disorders: a population-based analysis of the 2009-2010 Canadian Community Health Surveys.
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      we judged may be associated with time to first opioid prescription—chiropractic care, calendar year, frequency of health care visits, age, sex, smoking status, obesity, depression, anxiety, fibromyalgia, diabetes, and cardiovascular disease.
      To prevent overfitting of our regression model, we required a minimum sample of 120 patient records (ie, minimum of 10 events per category for each independent variable).
      • Katz MH.
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      We excluded independent variables with fewer than 50 observations to ensure that each variable had sufficient discriminant power to detect an association with opioid prescribing if such an association existed.
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      • Heels-Ansdell D
      • Wang L
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      • Walter SD.
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      We also explored variance inflation factors (VIFs) to assess multicollinearity among independent variables and considered VIFs ≥5 as problematic.
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      Data Analysis

      We generated frequencies for all relevant EMR data collected and reported categorical variables as proportions, normally distributed continuous data as the mean and standard deviation (SD), and skewed continuous data as the median and interquartile range (IQR). We compared baseline characteristics between chiropractic recipients and nonrecipients using a χ2 test for categorical variables (or Fisher exact test if there was a cell frequency of <5), independent t tests for normally distributed continuous variables, and the Mann-Whitney U test for skewed continuous variables.
      We performed a time-to-event analysis using a Cox proportional hazards regression model to assess the association between all 12 independent variables described above and time to first opioid prescription. We built a second model with the same 12 variables but with our exposure variable as early receipt of chiropractic care (ie, receipt of chiropractic services within 30 days of the index visit). To further increase confidence in our findings, we only considered an independent variable as statistically significant if it had a P value of ≤.01 in our adjusted models. We calculated unadjusted and adjusted hazard ratios (HRs) for our time-to-event analyses, their associated 99% confidence intervals (CIs), and corresponding P values. For our Cox regression models, we tested the proportional hazards assumption by checking the P value of the time-covariate interaction term for each independent variable using a time-dependent covariate analysis. We considered a P value of ≤.05 for the interaction term as significant. Calendar year was entered into our models as a time-dependent variable. We also checked the Kaplan-Meier and log-minus-log plots for our main exposure variable (chiropractic care or early chiropractic care) to verify the absence of nonproportionality. All data and comparative analyses were performed using SPSS v26.0 (IBM Corp, Armonk, NY).
      To help convey the magnitude of difference for our primary association of interest, we estimated the cumulative proportion of first opioid prescriptions received at 1 year among patients in our cohort who did and did not receive chiropractic care by using the following formula: P1 = 1 – (1 – P0) HR, where P1 is the cumulative proportion of first opioid prescriptions received by 1 year in the group that did receive chiropractic care, P0 is the cumulative proportion of first opioid prescriptions received by 1 year in the group of patients that did not receive chiropractic care, and HR is the association of chiropractic care with receiving an opioid prescription. We repeated this calculation for patients who did and did not receive early chiropractic care.

      Qualitative Phase

      Sampling

      As described elsewhere,
      • Emary PC
      • Oremus M
      • Mbuagbaw L
      • Busse JW.
      Association of chiropractic integration in an Ontario community health centre with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol.
      we used stratified purposive sampling
      • Collins KMT
      • Onwuegbuzie AJ
      • Jiao QG.
      A mixed methods investigation of mixed methods sampling designs in social and health science research.
      to select a subsample of chiropractic and nonchiropractic patients whose charts we examined in the quantitative phase to participate in 1-on-1 interviews. This was the first stage of integration between the quantitative and qualitative phases of our study.
      • Fetters MD
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      • Creswell JW.
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      We also recruited a purposive sample of GPs/NPs from Langs CHC. We obtained participant contact information from the Langs administration, and the lead author (P.C.E.) conducted recruitment via telephone or e-mail. Gift cards ($30 for patients, $10 for GPs/NPs) were offered as incentives. We used maximum variation
      • Collins KMT
      • Onwuegbuzie AJ
      • Jiao QG.
      A mixed methods investigation of mixed methods sampling designs in social and health science research.
      based on age, sex, and the number of years in practice (for GPs/NPs) or years attending the CHC (for patients) in choosing participants to ensure a range of perspectives and sociodemographic characteristics. We aimed to interview a minimum of 6 GPs/NPs and 12 patients,
      • Collins KMT
      • Onwuegbuzie AJ
      • Jiao QG.
      A mixed methods investigation of mixed methods sampling designs in social and health science research.
      with interviews continuing until the occurrence of data saturation (ie, the point at which no new information was obtained from participants in the GP/NP, chiropractic, and nonchiropractic groups).
      • Tashakkori A
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      Fundamental qualitative description
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      ,
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      was the methodological orientation we used to underpin the qualitative phase of our study.

      Data Collection

      The lead author (P.C.E.) conducted 1-on-1 (individual) semistructured interviews with participants. We chose individual interviews over focus groups because of the sensitive nature of our research topic and because participants could have been discouraged from sharing their full views on the subject (ie, opioid use) in the presence of other patients or peers. Interviews were conducted in a private office separate from the medical clinic at Langs CHC and were held either in-person (n = 20) or virtually (n = 3) using the Zoom videoconferencing application (Zoom Video Communications, Inc). Informed consent was obtained from participants before the start of each interview. Five members of our research team (P.C.E., A.L.B., M.O., L.M., J.W.B.) developed the interview guides (see Supplementary Files 2 and 3) based on our quantitative findings and relevant literature.
      • Busse JW
      • Wang L
      • Kamaleldin M
      • et al.
      Opioids for chronic noncancer pain: a systematic review and meta-analysis.
      ,
      • Busse JW
      • Craigie S
      • Juurlink DN
      • et al.
      Guideline for opioid therapy and chronic noncancer pain.
      ,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.

      Langs. Cambridge: Langs Community Health Centre. Available at: https://www.langs.org. Accessed January 31, 2022.

      Community Health Centres. Toronto: Ontario Ministry of Health and Long-Term Care; 2021. Available at:https://www.ontario.ca/page/community-health-centres. Accessed January 31, 2022.

      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF.
      Chiropractic integration within a community health centre: a cost description and partial analysis of cost-utility from the perspective of the institution.
      • Garner MJ
      • Aker P
      • Balon J
      • Birmingham M
      • Moher D
      • Keenan D
      • Manga P.
      Chiropractic care of musculoskeletal disorders in a unique population within Canadian community health centers.
      • Mior S
      • Gamble B
      • Barnsley J
      • Côté P
      • Côté E.
      Changes in primary care physician's management of low back pain in a model of interprofessional collaborative care: an uncontrolled before-after study.
      • Passmore SR
      • Toth A
      • Kanovsky J
      • Olin G.
      Initial integration of chiropractic services into a provincially funded inner city community health centre: a program description.
      ,
      • Manansala C
      • Passmore S
      • Pohlman K
      • Toth A
      • Olin G.
      Change in young people's spine pain following chiropractic care at a publicly funded healthcare facility in Canada.
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      Three of the 5 members (P.C.E., A.L.B., J.W.B.) had content expertise in the subject area of our study.
      We audio-recorded in-person interviews using MacIntosh recording software (Audio Recorder version 1.3, FIPLAB Limited, Chalfont St. Peter, Buckinghamshire, United Kingdom) and virtual interviews using Zoom's built-in recording feature. Field notes were taken after each interview by the lead author (P.C.E.) to document emergent themes and other observations. We sent interview transcripts and a summary of the results to participants for feedback or correction.
      • Creswell JW
      • Plano Clark VL
      Designing and Conducting Mixed Methods Research.

      Data Analysis

      All interview audio recordings were transferred into the software program, MAXQDA (Max Weber Qualitative Data Analysis, VERBI Software, Sozialforschung GmbH, Berlin, Germany) and transcribed by the lead author (P.C.E.) verbatim. Participant identifiers were removed, and a random sample of 15% of the transcripts was reviewed for accuracy by another member of the research team (J.D.). Two investigators (P.C.E., A.L.B.) independently coded all transcripts using an inductive content analytic approach
      • Bradshaw C
      • Atkinson S
      • Doody O.
      Employing a qualitative description approach in health care research.
      to descriptively summarize the information to ensure the “best fit to the data.”
      • Sandelowski M.
      Whatever happened to qualitative description?.
      We used open coding to develop concepts from the data and axial coding to relate these codes (or concepts) to one another and identify themes and subthemes.
      • Creswell JW
      • Plano Clark VL
      Designing and Conducting Mixed Methods Research.
      The 2 investigators met 3 times throughout the qualitative analysis (ie, after every 7 to 8 interviews) to compare their themes and arrive at a final, agreed-upon set of themes through discussion. These themes were then organized into tabular form, and representative quotes were selected for each theme/subtheme. As part of our data integration procedures (see Fig 1),
      • Creswell JW
      • Plano Clark VL
      Designing and Conducting Mixed Methods Research.
      ,
      • Fetters MD
      • Curry LA
      • Creswell JW.
      Achieving integration in mixed methods designs – principles and practices.
      we created a joint display table and used a contiguous narrative approach to combine our qualitative and quantitative results. Meta-inferences
      • Collins KMT
      • Onwuegbuzie AJ
      • Jiao QG.
      A mixed methods investigation of mixed methods sampling designs in social and health science research.
      ,
      • Tashakkori A
      • Teddlie C.
      Handbook of Mixed Methods in Social and Behavioural Research.
      were then drawn from the data. An audit trail of our coding and reflexive procedures was recorded throughout our analysis.
      • Bradshaw C
      • Atkinson S
      • Doody O.
      Employing a qualitative description approach in health care research.
      For investigator reflexivity, see Supplementary File 4.

      Results

      Quantitative Findings

      We identified 1166 patient records, and 945 met eligibility criteria for inclusion in our quantitative analysis (Fig 2).
      Fig 2
      Fig 2Flowchart of cohort inclusion for the quantitative (time-to-event) analysis.

      Cohort Characteristics

      The baseline characteristics (n = 945) are presented in Table 1. Among patients who received an initial opioid prescription during the 7-year study period (n = 227), most (75%) were prescribed opioids within 12 months after their first visit to the CHC. The survival curve for the time to first opioid prescription among the study cohort is presented in Supplementary File 5.
      Table 1Demographic and Clinical Characteristics of Patients From the Quantitative Chart Review (n = 945)
      VariableValue
      Values are expressed as the number (%) unless otherwise indicated.
      Age (y), mean (SD)52.4 (17.0)
      Sex
      • Male
      • Female


      416 (44.0)

      529 (56.0)
      General health
      • Smoker
      • Obese
        Patients with a body mass index of ≥30 kg/m2 were classified as obese.


      246 (26.0)

      101 (10.7)
      Comorbidities

      •Cardiovascular disease

      •Depression

      •Anxiety

      •Diabetes

      •Fibromyalgia


      482 (51.0)

      420 (44.4)

      396 (41.9)

      184 (19.5)

      57 (6.0)
      Year of index visit
      Year of index visit to the CHC for a noncancer back or neck pain diagnosis.
      • 2014
      • 2015
      • 2016
      • 2017
      • 2018
      • 2019
      • 2020


      299 (31.6)

      165 (17.5)

      138 (14.6)

      117 (12.4)

      71 (7.5)

      86 (9.1)

      69 (7.3)
      Frequency of health care visits, median (IQR)
      Health care visits constitute GP/NP and chiropractic visits.
      4 (3-11)
      Opioid prescription227 (24.0)
      Receipt of chiropractic care183 (19.4)
      CHC, community health center; GP/NP, general physician/nurse practitioner; IQR, interquartile range; SD, standard deviation.
      a Values are expressed as the number (%) unless otherwise indicated.
      b Patients with a body mass index of ≥30 kg/m2 were classified as obese.
      c Year of index visit to the CHC for a noncancer back or neck pain diagnosis.
      d Health care visits constitute GP/NP and chiropractic visits.

      Chiropractic Recipients vs Nonrecipients

      There were 19% of patients (183 of 945) who received chiropractic services. Of these, 48% (87 of 183) received chiropractic services within 30 days of their index visit. In comparison to nonrecipients, chiropractic recipients were more commonly female patients, depressed, or diabetic. Early chiropractic recipients had similar characteristics to those who did not receive early chiropractic services (see Supplementary File 6).

      Time-to-Event Analysis

      The regression analysis showed an inverse association between receipt vs nonreceipt of chiropractic care and opioid prescribing (HR, 0.48; 99% CI, 0.29-0.77) (Table 2). Thus, at 1 year, 51% of patients without chiropractic care received opioids vs 29% of patients who received chiropractic care. Among early chiropractic recipients, the risk of initiating a prescription for opioids was lower (HR, 0.29; 99% CI, 0.13-0.68) (see Supplementary File 7). Thus, at 1 year, 49% of patients without early chiropractic care received opioids compared to 18% of patients who received early chiropractic care (Fig 3). Patients whose index visit date was in a more recent calendar year were less likely to receive opioids (HR, 0.86; 99% CI, 0.76-0.97). A higher frequency of health care visits (HR, 1.02; 99% CI, 1.02-1.03), older age (HR, 1.02; 99% CI, 1.01-1.04), positive smoking status (HR, 1.62; 99% CI, 1.12-2.35), and depression (HR, 1.77; 99% CI, 1.20-2.61) were positively associated with receipt of opioids (Table 2). These associations were also found in our second regression model (see Supplementary File 7). All VIFs were less than 1.6, suggesting no important multicollinearity among independent variables.
      Table 2Unadjusted and Adjusted Hazard Ratios for the Risk of Opioid Prescription Among Patients With Noncancer Back or Neck Pain Presenting Between January 1, 2014, and December 31, 2020 (n = 945)
      HR >1 indicates shorter time to first opioid prescription.
      VariableUnivariateP ValueMultivariableP Value
      Unadjusted HR(99% CI)Adjusted HR(99% CI)
      Chiropractic care
      • Nonexposed
      • Exposed


      Reference

      0.94 (0.62-1.43)




      .713


      Reference

      0.48 (0.29-0.77)




      <.001
      Time (calendar year)
      Calendar year was measured at the patient's index visit date to the CHC for a noncancer spine pain diagnosis.
      0.81 (0.72-0.91)<.0010.86 (0.76-0.97).001
      Frequency of health care visits
      Health care visits constitute GP/NP and chiropractic visits.
      1.02 (1.02-1.03)<.0011.02 (1.02-1.03)<.001
      Age1.02 (1.01-1.03)<.0011.02 (1.01-1.04)<.001
      Sex
      • Female
      • Male


      Reference

      0.98 (0.70-1.39)




      .904


      Reference

      1.06 (0.73-1.52)




      .692
      Smoking status
      • Nonsmoker
      • Smoker


      Reference

      1.70 (1.19-2.43)




      <.001


      Reference

      1.62 (1.12-2.35)




      .001
      Obesity
      • Nonobese
      • Obese


      Reference

      1.19 (0.72-1.96)




      .369


      Reference

      0.92 (0.54-1.58)




      .692
      Depression
      • Absent
      • Present


      Reference

      1.58 (1.12-2.24)




      .001


      Reference

      1.77 (1.20-2.61)




      <.001
      Anxiety
      • Absent
      • Present


      Reference

      1.02 (0.72-1.44)




      .886


      Reference

      0.80 (0.54-1.18)




      .136
      Fibromyalgia
      • Absent
      • Present


      Reference

      1.74 (0.99-3.07)




      .012


      Reference

      1.00 (0.51-1.95)




      .993
      Diabetes
      • Absent
      • Present


      Reference

      1.44 (0.98-2.12)




      .014


      Reference

      1.07 (0.70-1.66)




      .674
      Cardiovascular disease
      • Absent
      • Present


      Reference

      1.43 (1.00-2.03)




      .009


      Reference

      0.80 (0.52-1.23)




      .181
      CHC, community health center; CI, confidence interval; GP/NP, general physician/nurse practitioner; HR, hazard ratio.
      a HR >1 indicates shorter time to first opioid prescription.
      b Calendar year was measured at the patient's index visit date to the CHC for a noncancer spine pain diagnosis.
      c Health care visits constitute GP/NP and chiropractic visits.
      Fig 3
      Fig 3Survival curves of the time to first opioid prescription among recipients and nonrecipients of chiropractic services (A), and recipients and nonrecipients of chiropractic services within the first 30 days after an index visit for a noncancer spinal pain diagnosis (B).
      Contrary to our predictions, older age was positively associated with receipt of opioids. We found that male sex, obesity, anxiety, fibromyalgia, diabetes, and cardiovascular disease were not associated with receipt of opioids in our sample (Table 2 and Supplementary File 7). We explored for interaction between receipt of chiropractic care and age, smoking, depression, or health care visit frequency, but none of the interaction terms were significant.

      Qualitative and Integrated Findings

      The majority (79%) of patients interviewed were women, most (86%) were either receiving disability benefits or were unemployed, and the majority (71%) had previously received at least 1 opioid prescription for noncancer spinal pain. Among patients and GPs/NPs, there was a large range of ages (33-82) and number of years in practice (GPs/NPs: 1-26) or years attending the CHC (patients: 2 to 43), demonstrating variability among participants (Table 3).
      Table 3Demographic and Clinical Characteristics of Participants From the Qualitative Interviews (n = 23)
      Value
      Values are expressed as the number (%) unless otherwise indicated.
      VariablePatients (n = 14)GPs/NPs (n = 9)
      Age (y), mean (SD)56.2 (14.3)47 (10.5)
      Sex
      • Male
      • Female


      3 (21.4)

      11 (78.6)


      2 (22.2)

      7 (77.8)
      Years attending CHC (patients)/years in practice (GPs/NPs), mean (SD)13 (11.6)13.4 (6.8)
      Completed postsecondary education or higher7 (50.0)9 (100)
      Receiving disability benefits/unemployed12 (85.7)0 (0)
      Opioid prescription10 (71.4)NA
      Receipt of chiropractic care8 (57.1)NA
      CHC, community health center; GP/NP, general physician/nurse practitioner; NA, not applicable; SD, standard deviation.
      a Values are expressed as the number (%) unless otherwise indicated.
      Twelve GPs/NPs were invited for interviews, and 9 participated. Of these, 4 were medical doctors, and 5 were nurse practitioners. Two medical doctors declined participation because of lack of time, and 1 nurse practitioner expressed interest but did not respond to further interview requests. Among patients, 23 were recruited, and 14 completed interviews (ie, 8 of 11 chiropractic recipients and 6 of 12 nonrecipients). Five patients scheduled interviews but canceled (2 chiropractic recipients, 3 nonrecipients), 2 scheduled interviews but did not attend (1 recipient, 1 nonrecipient), 1 was not interested, and 1 declined for health reasons. In total, 23 interviews were completed (14 patients, 9 GPs/NPs). The median duration of interviews were 38 minutes (range, 20-40) for GPs/NPs and 25 minutes (range, 19-56) for patients.
      Among all 23 participants, 3 GPs/NPs and 1 nonchiropractic patient made unsubstantive revisions to clarify statements from their interviews. No other participants requested corrections or content changes to their transcripts or results. We determined that data saturation had been reached when only 1 new code emerged from GP/NP interviews 7, 8, and 9; only 2 new codes emerged from chiropractic recipient interviews 7 and 8 (with no new codes from interview 8); and only 1 new code emerged from nonrecipient interview 4 (with no new codes from interviews 5 and 6), which concluded patient recruitment.

      Coding Tree

      We identified 37 codes across interviews and categorized these into the following 4 major themes: (1) patient self-efficacy, (2) accessibility of nonpharmacological services, (3) stigma regarding use of opioids, and (4) impact of treatment. Codes pertaining to patient self-efficacy were grouped into 2 subthemes, active vs passive approaches and resistance to taking medication. This latter subtheme was more frequent among interviews of chiropractic (4 of 8) vs nonchiropractic (2 of 6) patients. For instance:“I've been dealing with this pain for 10 years, and I'm not just a pill popping, believing [person]. [I'm] old school, take the pain until it's really extreme and then—oh gee, I better take an Advil—is kinda how I deal with my pain.” Doctor of Chiropractic (DC) Patient 1
      For our second theme, we created the subthemes lack of access and access to chiropractic services at Langs. Lack of access to nonpharmacological services (eg, chiropractic, physical therapy) was identified in nearly all (21 of 23) participant interviews and was reported by both GPs/NPs and patients as a common facilitator of opioid use.“It's that scenario where you have nothing else to offer, right? So, if you're trying to postpone heading into ‘opioid land’ and you still have something else to offer, it can definitely make a difference. . . . You probably go to meds sooner than you might otherwise because you don't have access to the intervention you'd really like.” GP/NP 7“When I was about 23 [years old], financially I wasn't able to go [to my chiropractor] anymore. So, that's when [my doctor] put me on the OxyContin and the Perc's.” DC Patient 7
      Our third theme captured codes related to the opioid crisis such as negative media coverage or lived experiences. Some patients also expressed a sense of judgment from others for using prescription opioids, as elucidated by the following participant:“It's been frustrating—so frustrating. Because the [opioid] crisis seemed to just fall right on me. Like, as though I'm part of the crisis. So, [as a result] every doctor doesn't want you on any kind of pain medication. They don't believe your pain. You know what I mean? It has really affected me. . . . I'm not an addict in any way. I never even ever think twice about taking that medication more than once, like, unprescribed. But I was definitely treated like I was [an addict].” Non-DC Patient 5
      The remaining codes related to patients’ or GPs/NPs’ perspectives on the impact of treatment, including subthemes of pain relief, functionality, and anxiety and fear surrounding opioid withdrawal. For example:“[For] my neck, sometimes, if I didn't go [to the chiropractor], I would really notice it in a couple months if I didn't go every, at least every 2 months, if not every month.” DC Patient 8“I do actually have patients on opioids that are actually working and it's because they're on opioids . . . that they continue to work full-time. And so, they're not the ones that I worry about so much because they clearly have functionality, and they don't show any behavioral stuff.” GP/NP 9
      And:“. . . terrifying. . . . Not being able to have [my] prescription filled is very frightening—and panic. You start having anxiety.” Non-DC Patient 4
      Further descriptions and frequency counts of each major theme, subthemes, and representative participant quotes are provided in Supplementary File 8. Qualitative and quantitative findings are shown together as a joint display in Table 4.
      Table 4Combined Display of the Quantitative Association Between Receipt of Chiropractic Services at Langs Community Health Center and Prescription of Opioids, Representative Qualitative Interview Quotes, and Meta-Inferences
      VariableQuantitative ResultsQualitative Interview QuotesMeta-Inferences
      Receipt of chiropractic care

      (n = 183)
      Negative association with receipt of opioids (adjusted HR, 0.48)Resistance to taking medication:

       • “I don't want to take any pill. It is better to bear the pain for some time rather than going for pills, or anything. [I'm] not a great believer in artificial pills.” DC Patient 2

       • “My thing for not wanting [opioids], I've lost way too many people, way too many friends, family, and I just know the destruction and devastation it does.” DC Patient 6

       • “[Before I came to Langs] I was on Percocet, OxyContin, Fentanyl. [I] got away from all that. It didn't [solve anything].” DC Patient 7

      Access to chiropractic services:

       • “[The chiropractic program at Langs has] been helpful to avoid going the route of opioids sometimes. . . . In some cases, people weren't responding to what they were already on and we kind of maximized the dosing on that, and they were looking for more pain relief and one of the options might have been to add in an opioid; but because we had access to chiropractic . . . that sort of, kind of, kept things at bay and they were able to manage.” GP/NP 9

       • “The increased number of alternative therapies that you [have to] offer them, the more likely you are to avoid an opioid prescription.” GP/NP 4
      The risk of receiving opioids was 52% lower in chiropractic recipients vs nonrecipients. Patients who were referred by their GP/NP for chiropractic services at Langs may have been more resistant to taking opioids than patients who were not referred for chiropractic services. Access to chiropractic treatment also gave GPs/NPs another nonopioid pain management option.
      Receipt of early chiropractic care
      Defined as receipt of chiropractic services within 30 days of the patient's index visit.
      (n = 87)
      Negative association with receipt of opioids (adjusted HR, 0.29) • “I see the difference between patients that have access [to nonpharmacological services] and don't have access. . . . Any patients that have access to all those resources and can get them started right off the bat, I'm rarely giving them opioids. . . . People that don't have access to anything, end up on opioids, just more often.” GP/NP 9

       • “I do have a patient . . . who got referred [into the chiropractic program] right away and has not ever, opioids have never been on the table.” GP/NP 1
      The risk of receiving opioids was 71% lower in patients who received chiropractic services within 30 days of their index visit. When accessed as a first-line treatment option, chiropractic care may have helped to delay, and in some cases prevent, the prescription of opioids.
      Index visit in more recent calendar year (n = 945)Negative association with receipt of opioids (adjusted HR, 0.86) • “I haven't started very [many] new people [on opioids]. . . . That's the real shift. And I notice this in my colleagues, because my colleagues are all 20 years younger than me, and they don't start them nearly as readily as I did say 10 years ago, 15 years ago.” GP/NP 7

       • “In the last 4 or 5 years [here at Langs], we've worked even harder at getting people off opioids.” GP/NP 3
      Patients whose index visit date was in a more recent calendar year were less likely to receive opioids. GPs/NPs at Langs have made a concerted effort in recent years to reduce opioid prescribing.
      DC, doctor of chiropractic; GP/NP, general physician/nurse practitioner; HR, hazard ratio.
      a Defined as receipt of chiropractic services within 30 days of the patient's index visit.

      Discussion

      This study was one of the first to examine the relationship between chiropractic integration and opioid use among vulnerable patients with noncancer spinal pain in a CHC setting
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      ,
      • Prater C
      • Tepe M
      • Battaglia P.
      Integrating a multidisciplinary pain team and chiropractic care in a community health center: an observational study of managing chronic spinal pain.
      and the first to do so using a mixed methods approach. In our quantitative analysis, we found that receipt of chiropractic care was associated with a decreased likelihood of receiving an opioid prescription, and our follow-up interviews identified several potential influencing factors in this relationship. Our quantitative results are consistent with those of other uncontrolled observational studies.
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      ,
      Correction: Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      For instance, a systematic review and meta-analysis of 6 cohort studies
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      found that patients with noncancer back or neck pain who received chiropractic services were nearly two-thirds less likely than nonchiropractic users to be prescribed opioids (pooled odds ratio, 0.36; 95% CI, 0.30-0.43). In 2 more recent studies,
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      ,
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      the risk of filling an opioid prescription among US adults
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      and older Medicare beneficiaries
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      with noncancer spinal pain was reduced by half for recipients of chiropractic services. In keeping with our findings, this reduction was greater among patients who saw a chiropractor within the first 30 days of treatment.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      ,
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      An association between reduced opioid use for spinal pain with early access to nonpharmacological services (eg, chiropractic, physical therapy) has also been reported by others.
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      ,
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      ,
      Correction: Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      ,
      • Horn ME
      • George SZ
      • Fritz JM.
      Influence of initial provider on health care utilization in patients seeking care for neck pain.
      We gained several insights into our quantitative findings by integrating quantitative and qualitative methods. Based on our interviews, we perceive that patients who were referred for chiropractic services at Langs CHC may have been more resistant to taking medication in general and opioids in particular than patients who were not referred for chiropractic services. GPs/NPs indicated that access to chiropractic treatment gave them another nonopioid pain management option. In addition, a negative stigma regarding use of prescription opioids was identified by several chiropractic patients and GPs/NPs as a barrier to opioid use. These factors may help explain why chiropractic recipients were less likely to be prescribed opioids. We also found that when accessed as a first-line treatment, chiropractic care may have helped to delay, and in some cases prevent, opioid prescription. Our data suggest that by 1 year, access to chiropractic care resulted in an additional 22% of patients not receiving a prescription for opioids. When chiropractic care was accessed within 30 days of visiting the CHC, an additional 31% of patients avoided an opioid prescription. Thus, it appears that earlier access to chiropractic care may have had a greater protective effect in reducing the number of people obtaining opioid prescriptions.
      Similar to previous research,
      • Busse JW
      • Craigie S
      • Juurlink DN
      • et al.
      Guideline for opioid therapy and chronic noncancer pain.
      ,
      • Lisi AJ
      • Corcoran KL
      • DeRycke EC
      • et al.
      Opioid use among veterans of recent wars receiving Veterans Affairs chiropractic care.
      • Carroll LJ
      • Hogg-Johnson S
      • van der Velde G
      • et al.
      Course and prognostic factors for neck pain in the general population: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders.
      • Katz MH.
      Multivariable analysis: a primer for readers of medical research.
      we found that positive smoking status and comorbid depression were strongly associated with opioid use in our sample (ie, increased risk of 62% and 77%, respectively). In the 2017 Canadian opioid guideline,
      • Busse JW
      • Craigie S
      • Juurlink DN
      • et al.
      Guideline for opioid therapy and chronic noncancer pain.
      we found that comorbid mental illness was associated with an increased risk of opioid use disorder, as well as nonfatal and fatal opioid overdose when chronic pain patients were prescribed opioids. As such, a weak/conditional recommendation was made to avoid prescribing opioids to patients with active psychiatric disorders until their comorbid mental illness has been stabilized.
      • Busse JW
      • Craigie S
      • Juurlink DN
      • et al.
      Guideline for opioid therapy and chronic noncancer pain.
      Our current findings suggest that patients with comorbid depression were more likely to receive prescription opioids, which is cause for concern.
      Our findings and those of other researchers suggest that chiropractic services are consistently associated with a reduced risk of opioid prescribing, as well as improved patient outcomes and potential for cost savings (eg, reductions in GP/NP visits, advanced imaging, and specialist referrals).
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.
      ,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF.
      Chiropractic integration within a community health centre: a cost description and partial analysis of cost-utility from the perspective of the institution.
      • Garner MJ
      • Aker P
      • Balon J
      • Birmingham M
      • Moher D
      • Keenan D
      • Manga P.
      Chiropractic care of musculoskeletal disorders in a unique population within Canadian community health centers.
      • Mior S
      • Gamble B
      • Barnsley J
      • Côté P
      • Côté E.
      Changes in primary care physician's management of low back pain in a model of interprofessional collaborative care: an uncontrolled before-after study.
      • Passmore SR
      • Toth A
      • Kanovsky J
      • Olin G.
      Initial integration of chiropractic services into a provincially funded inner city community health centre: a program description.

      Centre for Effective Practice. Primary care low back pain pilot evaluation: final report. Toronto: Centre for Effective Practice; 2017.

      • Manansala C
      • Passmore S
      • Pohlman K
      • Toth A
      • Olin G.
      Change in young people's spine pain following chiropractic care at a publicly funded healthcare facility in Canada.
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      ,
      • Prater C
      • Tepe M
      • Battaglia P.
      Integrating a multidisciplinary pain team and chiropractic care in a community health center: an observational study of managing chronic spinal pain.
      As such, with further integration of chiropractic services into primary care centers,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.
      ,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF.
      Chiropractic integration within a community health centre: a cost description and partial analysis of cost-utility from the perspective of the institution.
      • Garner MJ
      • Aker P
      • Balon J
      • Birmingham M
      • Moher D
      • Keenan D
      • Manga P.
      Chiropractic care of musculoskeletal disorders in a unique population within Canadian community health centers.
      • Mior S
      • Gamble B
      • Barnsley J
      • Côté P
      • Côté E.
      Changes in primary care physician's management of low back pain in a model of interprofessional collaborative care: an uncontrolled before-after study.
      • Passmore SR
      • Toth A
      • Kanovsky J
      • Olin G.
      Initial integration of chiropractic services into a provincially funded inner city community health centre: a program description.

      Centre for Effective Practice. Primary care low back pain pilot evaluation: final report. Toronto: Centre for Effective Practice; 2017.

      • Manansala C
      • Passmore S
      • Pohlman K
      • Toth A
      • Olin G.
      Change in young people's spine pain following chiropractic care at a publicly funded healthcare facility in Canada.
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      ,
      • Prater C
      • Tepe M
      • Battaglia P.
      Integrating a multidisciplinary pain team and chiropractic care in a community health center: an observational study of managing chronic spinal pain.
      the potential benefits for the opioid crisis, including how these patients are managed in CHCs and other health care settings, could be substantial.

      Strengths

      First, we included a robust set of potential confounders in our multivariable regression models to minimize the possibility of residual confounding. Second, we prespecified the anticipated direction of association for each independent variable in our regression models and set our significance level to 1% to provide greater confidence in our findings. Third, we controlled for the calendar year in our analyses to account for policy changes in opioid prescribing. Additional strengths included direct data export from the EMR to avoid extraction errors,
      • Vassar M
      • Holzmann M.
      The retrospective chart review: important methodological considerations.
      limited missing data (<1%), and validation of our qualitative data via member-checking. The qualitative component of our study also provided a richer understanding of our quantitative findings.

      Limitations and Future Studies

      In the quantitative phase of our study, a limitation was the retrospective design, and certain variables that may be important to consider were unavailable. For example, due to the constraints of data recorded in Langs EMR, we were unable to extract information on baseline spine-related pain (ie, severity/chronicity) or other cointerventions that patients may have received outside of the CHC. Moreover, we were unable to include race/ethnicity or other social determinants of health as possible covariates in our analysis,
      • Moriya AS
      • Xu L.
      The complex relationships among race/ethnicity, social determinants, and opioid utilization.
      as these factors were not captured in the administrative database that we used. However, our findings regarding the association between receipt of chiropractic services and reduced opioid prescriptions were consistent with other studies that controlled for the duration of low back or neck pain.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      ,
      Correction: Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      ,
      • Horn ME
      • George SZ
      • Fritz JM.
      Influence of initial provider on health care utilization in patients seeking care for neck pain.
      Moreover, due to socioeconomic disadvantages,
      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF
      • Bolton JE.
      Management of back pain-related disorders in a community with limited access to health care services: a description of integration of chiropractors as service providers.

      Langs. Cambridge: Langs Community Health Centre. Available at: https://www.langs.org. Accessed January 31, 2022.

      Community Health Centres. Toronto: Ontario Ministry of Health and Long-Term Care; 2021. Available at:https://www.ontario.ca/page/community-health-centres. Accessed January 31, 2022.

      • Emary PC
      • Brown AL
      • Cameron DF
      • Pessoa AF.
      Chiropractic integration within a community health centre: a cost description and partial analysis of cost-utility from the perspective of the institution.
      • Garner MJ
      • Aker P
      • Balon J
      • Birmingham M
      • Moher D
      • Keenan D
      • Manga P.
      Chiropractic care of musculoskeletal disorders in a unique population within Canadian community health centers.
      • Mior S
      • Gamble B
      • Barnsley J
      • Côté P
      • Côté E.
      Changes in primary care physician's management of low back pain in a model of interprofessional collaborative care: an uncontrolled before-after study.
      • Passmore SR
      • Toth A
      • Kanovsky J
      • Olin G.
      Initial integration of chiropractic services into a provincially funded inner city community health centre: a program description.
      ,
      • Manansala C
      • Passmore S
      • Pohlman K
      • Toth A
      • Olin G.
      Change in young people's spine pain following chiropractic care at a publicly funded healthcare facility in Canada.
      ,
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      most Langs CHC patients would be unlikely to have accessed private health care services elsewhere. A second limitation is that our primary outcome, time to first opioid prescription, is a surrogate for patient-centered outcomes, such as pain reduction or functional improvement. Third, as highlighted by our interviews, recipients of chiropractic care may have been prognostically different from nonrecipients despite our adjustments for confounding. Notwithstanding, recipients had a higher prevalence of depression, which, based on our data, should have increased their risk of opioid use (see crude association under the “Univariate” column in Table 2). However, when we controlled for depression in our adjusted analyses, recipients had a lower risk of opioid receipt. Fourth, a limitation in using a sequential mixed methods design (ie, quantitative followed by qualitative) was that 11 months elapsed between our quantitative and qualitative data collection. As such, some individuals whom we attempted to recruit from the larger cohort were no longer available for interviews (eg, moved out of city, phone number no longer in service, or were deceased). Fifth, a limitation of the qualitative phase of our study is that we did not pilot-test our interview guides. However, 1-week in advance of participant interviews, patients and GPs/NPs received an information form containing examples of their interview questions. Sixth, and in line with our published protocol,
      • Emary PC
      • Oremus M
      • Mbuagbaw L
      • Busse JW.
      Association of chiropractic integration in an Ontario community health centre with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol.
      we interviewed patients and GPs/NPs to gain their perspectives on chiropractic integration at Langs CHC and its impact on opioid prescribing. However, the input of other stakeholders, such as administrators, chiropractors, or other allied health professionals (eg, nurses, dieticians, or physical therapists), might have revealed additional themes and subthemes to inform our research question. Seventh, as reported in Supplementary File 4 (see “Relationship with Participants”), a previous therapeutic relationship had been established between the lead author (P.C.E.) and 2 of the 8 chiropractic patients who were interviewed for this study. This may have influenced the results in these 2 interviews; however, in neither case was care being provided at the time of the interview. A final limitation of our mixed methods study is the findings may be generalizable to some, but not all, clinic programs outside of Langs CHC.
      Although our results and those of previous studies on the association between chiropractic care and prescription opioid use are promising,
      • Passmore S
      • Manansala C
      • Malone Q
      • Toth EA
      • Olin GM
      162. Opioid usage patterns, patient characteristics, and the role of chiropractic services in a publicly funded inner city health care facility.
      • Corcoran KL
      • Bastian LA
      • Gunderson CG
      • Steffens C
      • Brackett A
      • Lisi AJ.
      Association between chiropractic use and opioid receipt among patients with spinal pain: a systematic review and meta-analysis.
      • Kazis LE
      • Ameli O
      • Rothendler J
      • et al.
      Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      • Whedon JM
      • Toler AWJ
      • Kazal LA
      • Bezdjian S
      • Goehl JM
      • Greenstein J.
      Impact of chiropractic care on use of prescription opioids in patients with spinal pain.
      • Whedon JM
      • Uptmor S
      • Toler AWJ
      • Bezdjian S
      • MacKenzie TA
      • Kazal LA Jr.
      Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study.
      ,
      Correction: Observational retrospective study of the association of initial healthcare provider for new-onset low back pain with early and long-term opioid use.
      observational research is prone to selection bias. As such, well-designed randomized controlled trials (eg, Goertz et al
      • Goertz CM
      • Long CR
      • Vining RD
      • Pohlman KA
      • Walter J
      • Coulter I.
      Effect of usual medical care plus chiropractic care vs usual medical care alone on pain and disability among US service members with low back pain: a comparative effectiveness clinical trial.
      ) are urgently needed to confirm or refute these findings. A multistage, mixed methods, randomized controlled trial is needed to further explore our findings.

      Conclusion

      Our analysis found that patients with spine pain who received chiropractic care were less likely to receive opioids compared to patients who did not receive chiropractic care. This relationship was most pronounced among patients with early access to chiropractic services. Four themes emerged in our qualitative interviews, including patient self-efficacy, access to chiropractic services, stigma regarding use of opioids, and impact of treatment, which provide a richer understanding of this association.

      Acknowledgments

      The authors acknowledge Jomin Joseph, Decision Support Specialist at Compass Community Health, for his invaluable assistance with the electronic medical record data extraction for this project.

      Funding Sources and Conflicts of Interest

      This project was supported by a research grant from the Canadian Chiropractic Research Foundation. P.C.E. is supported by grants from McMaster University and the NCMIC Foundation outside of the submitted work. No conflicts of interest were reported for this study.

      Contributorship Information

      Concept development (provided idea for the research): P.C.E., M.O., L.M., J.W.B.
      Design (planned the methods to generate the results): P.C.E., M.O., L.M., J.W.B.
      Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): P.C.E., M.O., L.M., J.W.B.
      Data collection/processing (responsible for experiments, patient management, organization, or reporting data): P.C.E., A.L.B., D.F.C., J.D.
      Analysis/interpretation (responsible for statistical analysis, evaluation, and presentation of the results): P.C.E., A.L.B.
      Literature search (performed the literature search): P.C.E.
      Writing (responsible for writing a substantive part of the manuscript): P.C.E.
      Critical review (revised manuscript for intellectual content, this does not relate to spelling and grammar checking): P.C.E., A.L.B., M.O., L.M., D.F.C., J.D., J.W.B.
      Practical Applications
      • Our analysis found that receipt of chiropractic care was associated with a large decrease in opioid prescribing.
      • When accessed as a first-line treatment, chiropractic care may have helped to delay and, in some cases, prevent opioid prescription.
      • Our qualitative findings suggested that patient self-efficacy, access to chiropractic services, opioid stigma, and treatment impact were important influencing factors.
      • Our findings, combined with those of other researchers, suggest that further integration of chiropractic services into primary care centers could positively affect the opioid crisis.

      Appendix. Supplementary materials

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