The smallest worthwhile change on function from a self-management intervention for non-persistent low back pain.

PURPOSE: To determine: (1) the smallest change in function patients would need to see following a self-management intervention for low back pain (LBP) to consider it worthwhile; (2) the association between patient-related factors and the magnitude of the smallest worthwhile change. METHODS: A cross-sectional analysis of 212 participants of the TEXT4myBACK randomised trial was conducted. At baseline, participants nominated the smallest change in function (0-30 scale) following a self-management program they would need to reach to consider it worthwhile. A multivariate regression model estimated the effects of demographic, comorbidities, lifestyle and LBP-related factors on the smallest worthwhile change estimates. RESULTS: On average, people with LBP need to experience an improvement of at least 9.4 points (SD: 5.7) in function to consider a self-management intervention worthwhile. Only baseline function severity was significantly associated with the smallest worthwhile estimate (-0.60; 95%CI - 0.76, - 0.44). CONCLUSION: On average, an improvement of 9.4 points (or 31%) in function is considered by people with LBP as the smallest change that makes self-management worthwhile. Those with lower levels of function needed to experience greater improvements.