Objective: To investigate whether 3 distinct patterns of reactions to chiropractic care predict early favorable treatment outcome in patients with persistent low back pain. Design and Setting: Multicenter, clinic-based prospective outcome study with standardized interview questionnaires conducted in private chiropractic practices in Sweden. Study Subjects: Previously compliant chiropractors were invited to participate in the study. A maximum of 20 consecutive patients (per chiropractor) who sought chiropractic care for low back pain with or without sciatica with a duration of more than 2 weeks at the time of consultation and for a minimum of 30 days total during the past year. intervention: Chiropractic management as decided by the treating chiropractor. Outcome and Predictor Variables: Improvement was defined at the 4th visit as self-reported "definitely improved" (the best of 5 choices). The hypothesized most favorable prognostic group had immediate improvement reported on the 1st visit, reduced pain intensity reported on the 2nd visit, reduced disability reported on the 2nd visit, and a common reaction or no reaction reported on the 2nd visit. The hypothesized least favorable prognostic group had no immediate improvement on the 1st visit, no reduction of pain intensity on the 2nd visit, no reduced disability on the 2nd visit, and no reaction or an uncommon reaction reported on the 2nd visit. The hypothesized intermediate prognostic group included all patients who did not fit into the hypothesized most favorable or least favorable groups. Covariables: Age, sex, pain intensity during past 24 hours, description of disability, duration and pattern of pain during present attack, duration and pattern of pain during past 12 months. Analysis of Data: The 3 predictor-groups were cross-tabulated against the outcome variable and the other covariates. Results: Of the 115 patients in the most favorable prognostic group, 84% (95%, confidence interval, 77-91) reported to be "definitely improved" by the 4th visit versus 63% (59-67) of the 384 patients in the intermediate prognostic group, and 30% (22-38) of the 116 patients in the least favorable prognostic group. No major interactions from the covariates could explain these results. Conclusion: Among chiropractic patients with persistent low back pain, it is possible to predict which patients will report definite improvement early in the course of treatment.
