Responsiveness and Minimal Important Change of the Pain Self-Efficacy Questionnaire and Short Forms in Patients With Chronic Low Back Pain.

UNLABELLED: The Pain Self-Efficacy Questionnaire (PSEQ) is a valid and reliable patient-reported instrument used to assess pain self-efficacy in patients with chronic low back pain (CLBP). Recently, the 2-item (PSEQ-2) and the 4-item (PSEQ-4) short versions were developed showing satisfactory measurement properties in mixed populations with chronic pain. The aim of this study was to examine responsiveness and minimal important change (MIC) of PSEQ, PSEQ-2, and PSEQ-4 in patients with CLBP. We used a sample of 104 patients undergoing multimodal physical therapy designed to partly change pain self-efficacy beliefs. Responsiveness was assessed by testing 16 a priori formulated hypotheses regarding effect sizes, areas under the curve, and correlations with changes in other instruments measuring other constructs. The MIC was calculated using an external anchor specific for pain self-efficacy and the receiver operator characteristic (ROC) method. The PSEQ and the PSEQ-4 met all hypotheses, whereas the PSEQ-2 met all but 1. The MICs were 5.5 for the PSEQ (9% of the scale range) and 1.5 for PSEQ-2 (13% scale range) and PSEQ-4 (6% scale range). MIC values were different for patients with low or high baseline values for all 3 instruments. The PSEQ and its short versions are adequately responsive instruments in patients with CLBP. PERSPECTIVE: This study suggests that the PSEQ and its short versions are responsive measures of pain self-efficacy in patients with CLBP, adding to previous literature on their validity and reliability. Considering their similar responsiveness, the 4-item PSEQ could replace the original 10-item version in busy clinical or research settings.