The Nordic Back Pain Subpopulation Program: Demographic and Clinical Predictors for Outcome in Patients Receiving Chiropractic Treatment for Persistent Low–Back Pain

Abstract 

Objective

To identify demographic and clinic-related predictors for successful outcome in patients with persistent low-back pain who received chiropractic treatment.

Design

Prospective uncontrolled multicenter study with internal control groups.

Subjects

Each of 115 Norwegian chiropractors, out of 205 invited, were asked to recruit 10 consecutive patients who had low-back pain for at least 2 weeks at the time of consultation and a minimum of 30 days altogether within the preceding year. In all, 875 patients were included at baseline. The response rates at the fourth visit and at 3 and 12 months were 799, 598, and 512, respectively.

Methods

Baseline data were obtained through questionnaires administered to chiropractic patients and to their treating chiropractors; clinical information was obtained through questionnaires at the fourth visit from patients and chiropractors. Outcome was obtained from patients at the fourth visit. Mail surveys of patients were conducted after 3 and 12 months, and additional information was obtained from chiropractors at 12 months in relation to treatment history.

Potential Predictors

Demography and information on past and present history, clinical findings, and prognosis.

Outcome Variable

Number of low-back pain–free patients (defined as those with a maximum pain score of 1/10 and a maximum Oswestry score of 15/100).

Data Analysis

Positive predictive values and relative risks were calculated for each categorized predictor variable singly and in combination in relation to being low-back pain free at the 3 follow-up surveys.

Results

Treatment outcome at the fourth visit was best predicted by a model containing the following 5 variables: sex, social benefit, severity of pain, duration of continuous pain at first consultation, and additional neck pain (odds ratios between 2.2 and 4.3). A similar profile was found at 3 months, but 2 different variables (relating to disability) were the final variables in relation to the 12-month status. These final models were best at predicting absence of treatment success. Being low-back pain free at the fourth visit was a strong predictor for being low-back pain free both at 3 months and 12 months, with relative risks of 3.0 (2.2-4.8) and 3.1 (1.5-6.5), respectively.

Conclusion

In patients with persistent low-back pain, it is possible to exclude from treatment those who are unlikely to become low-back pain free after chiropractic care and to do this before they have been examined clinically. Early recovery is a strong predictor for outcome up to 1 year later.