Predictors of outcome in patients with (sub) acute low back pain differ across treatment groups

STUDY DESIGN.: Prospective study with 6 weeks of follow-up. OBJECTIVE.: To examine the predictors of outcome for patients with (sub)acute low back pain (LBP) receiving usual care (UC) or a minimal intervention strategy (MIS) aimed at psychosocial factors. SUMMARY OF BACKGROUND DATA.: A randomized controlled trial in general practice showed no differences in average effect between UC and MIS. METHODS.: Socio-demographic variables, characteristics of LBP, and psychosocial factors were included as potential predictors of outcome. The outcome clinically important improvement was defined as a reduction of at least 30% on functional disability plus patient perceived recovery. Logistic regression analyses were used to study the associations between predictors and outcome at 6 weeks follow-up. RESULTS.: In the UC group (n = 163), the multivariable model included a shorter duration of the LBP episode, few previous episodes, less pain catastrophizing, and good perceived general health. The area under the curve (AUC) of the model was 0.77 (95% confidence interval, 0.70-0.85). In the MIS group (n = 142), the multivariable model included less somatizing symptoms, more solicitous responses by an important other, lower perceived risk for chronic LBP, more fear avoidance beliefs, higher level of education, and shorter duration of the LBP episode. This AUC was 0.78 (95% confidence interval, 0.71-0.86). CONCLUSIONS.: As we found two different profiles, our approach may contribute to the important question: what intervention works for whom? ©2006, Lippincott Williams & Wilkins, Inc.