The Nordic back pain subpopulation program: Can patient reactions to the first chiropractic treatment predict early favorable treatment outcome in nonpersistent low back pain?

Objective: To investigate whether 3 distinct patterns of reactions to chiropractic care can predict early favorable treatment outcome in patients with nonpersistent low back pain (LBP). Design: Multicenter practice-based predictive validity study. Study Subjects: Sixty private practice chiropractors in Sweden recruited a maximum of 20 consecutive patients with LBP each, with a duration of less than 2 weeks at the time of consultation and a maximum of 30 days totally over the past year. Methods: Chiropractic management was decided on by the treating chiropractor. The outcome variable was self-reported "definite improvement" at the fourth visit. The predictor variables included 3 hypothesized prognostic groups (best, intermediate, and least favorable) on the basis of clinical information collected at baseline and at the second visit. The covariates included age, sex, pain intensity during the past 24 hours, description of disability, duration and pattern of pain during the present attack, and duration and pattern of pain during the past 12 months. The 3 predictor groups were cross-tabulated against the outcome variable and the other covariates. Backward stepwise logistic regression was performed to test for confounding or modification from relevant covariates. Results: Information was provided on 708 patients, of which 674 questionnaires were valid. Of the 223 patients in the hypothesized best prognostic group, 91% (95% CI, 79-100) reported to be "definitely improved" by the fourth visit, vs 76% (72-80) of the 420 patients in the intermediate prognostic group, and 36% (19-53) of the 31 patients in the least favorable prognostic group. These results were not altered after controlling for the covariates. Conclusion: For chiropractic patients with nonpersistent LBP, these findings show that it is possible to predict already by the second visit which patients may or may not report improvement at the fourth visit.