A Responsiveness Analysis of the Subgroups for Targeted Treatment (STarT) Back Screening Tool in Patients With Nonspecific Low Back Pain

BACKGROUND: The Subgroups for Targeted Treatment (STarT) Back Screening Tool (SBST) screens patients with low back pain and directs them to different levels of physical therapy treatment. The SBST is also used to monitor changes in a range of modifiable prognostic factors. However, the current evidence on the responsiveness of the SBST is limited. OBJECTIVES: To test the responsiveness of the SBST at 6 weeks and 6 months. METHODS: This measurement property study is a secondary analysis of data from 2 previous studies that included 348 participants with nonspecific low back pain. All participants were assessed at baseline, 6 weeks, and 6 months. To detect clinical changes, the SBST was compared to 3 one-dimensional constructs: global perceived effect, disability, and pain intensity. To assess responsiveness. we tested 15 specific predefined hypotheses based on correlation, effect size, and receiver operating characteristic curve analyses. If 75% or more of the hypotheses were accepted, then responsiveness was considered to be high. RESULTS: Most of the hypotheses were accepted. Testing the SBST as a continuous score, 857% and 87.5% of the hypotheses were accepted at 6 weeks and 6 months, respectively. For mediumand high-risk subgroups, 85.7% and 875% of the hypotheses were accepted at 6 weeks and 6 months. The low-risk subgroup had 42.9% of the hypotheses accepted at 6 weeks and 100% of the hypotheses accepted at 6 months. CONCLUSION: The SBST had high responsiveness at 6 weeks in subgroups of patients with a medium and high risk, and poor responsiveness in those with a low risk, of persistent disability. The SBST has high responsiveness in all SBST subgroups at 6 months. Clinicians can confidently use the SBST to measure changes over time in terms of subgroups. (AU)