RESUMEN
Investigating how individual characteristics modify treatment effects can improve understanding, interpretation, and translation of trial findings. The purpose of this secondary analysis was to identify treatment effect modifiers of the MI-NAV trial, a 3 arm, parallel randomized controlled trial which compared motivational interviewing and stratified vocational advice intervention in addition to usual case management (UC), to UC alone. This study included (n = 514) participants with musculoskeletal disorders on sick leave for at least 50% of their contracted work hours for at least 7 consecutive weeks with the Norwegian Labour and Welfare Administration. Sickness absence days was the primary outcome, measured from baseline assessment date until the 6-month follow-up. Potential treatment effect modifiers, identified a priori and informed by expert consultation and literature, were evaluated using linear regression models and statistical interaction tests. For motivational interviewing versus UC, age (mean difference [MD] -.7, 95% confidence interval [CI] -1.5 to .2; P = .13) and self-perceived health status (MD -.3, 95% CI -.7 to .1; P = .19) were identified as potential effect modifiers (P ≤ .2). For stratified vocational advice intervention versus UC, analgesic medication use (MD -26.2, 95% CI -45.7 to -6.7; P = .009) was identified as a treatment effect modifier (P ≤ .05). These findings may assist in more targeted treatment adaptation and translation as well as the planning of future clinical trials. PERSPECTIVE: This secondary analysis of the MI-NAV trial found that analgesic medication use, age, and self-perceived health may modify the effect of 2 vocational interventions on reducing sickness absence in people with musculoskeletal disorders.
RESUMEN
Exercise leads to clinically meaningful pain reductions in people with chronic low back pain and is recommended as a first line treatment. The benefits of exercise for chronic low back pain decrease over time with a lack of long-term exercise adherence as a potential reason for this decreasing effect. We aimed to identify the barriers and enablers to exercise adherence from the perspective of people with chronic low back pain. This qualitative study was underpinned by a constructivist epistemology and used a critical realist ontological perspective. Adults (18-65 years) with chronic low back pain who had exercised since the onset of their back pain were recruited to participate in focus groups and individual interviews. Audio data were transcribed and then analysed in 2 stages 1) inductive coding using reflexive thematic analysis, followed by 2) deductive analysis through mapping codes onto the Theoretical Domains Framework. Five enablers and 3 barriers were identified across 6 of the 14 Theoretical Domain Framework domains. Exercise identity and confidence in deciding to self-manage pain were enablers, whereas beliefs about the consequences of exercise, exercise context, and relationships could function as either barriers or enablers. These barriers and enablers were complex and fluid, with participants reporting conflicting barriers and enablers that varied, depending on context. These findings improve our understanding of the barriers and enablers to exercise adherence from the individual perspective of people with chronic low back pain and can be utilised for more effective exercise treatment in this population. PERSPECTIVE: This article presents the barriers and enablers to exercise adherence from the perspective of people with chronic low back pain. These perspectives may aid to individualise and optimise exercise treatment, improve its long-term adherence and therefore its effectiveness for chronic low back pain.
