Cost-effectiveness of 40-hour versus 100-hour vocational rehabilitation on work participation for workers on sick leave due to subacute or chronic musculoskeletal pain: study protocol for a randomized controlled trial

Although vocational rehabilitation is a widely advocated intervention for workers on sick leave due to subacute or chronic nonspecific musculoskeletal pain, the optimal dosage of effective and cost-effective vocational rehabilitation remains unknown. The objective of this paper is to describe the design of a non-inferiority trial evaluating the effectiveness and cost-effectiveness of 40-h multidisciplinary vocational rehabilitation compared with 100-h multidisciplinary vocational rehabilitation on work participation for workers on sick leave due to subacute or chronic musculoskeletal pain. A non-inferiority study design will be applied. The study population consists of workers who are on part-time or full-time sick leave due to subacute or chronic nonspecific musculoskeletal pain. Two multidisciplinary vocational rehabilitation programs following the bio-psychosocial approach will be evaluated in this study: 40-h vocational rehabilitation and 100-h vocational rehabilitation, both delivered over a maximum of 15 weeks. The 100-h vocational rehabilitation comprises five modules: work participation coordination, graded activity, cognitive behavioral therapy, group education, and relaxation. The 40-h vocational rehabilitation comprises work participation coordination and a well-reasoned choice from the other four modules. Four rehabilitation centers will participate in this study, each delivering both interventions. Patients will be randomized into one of the interventions, stratified for the duration of sick leave ( <6 weeks or ≥ 6 weeks) and type of sick leave (part-time or full-time). The primary outcome is work participation, measured by self-reported sick leave days, and will be assessed at baseline, mid-term, discharge, and at 2, 4, 6, 8, 10, and 12 months follow-up. Secondary outcomes are work ability, disability, quality of life, and physical functioning and will be assessed at baseline, discharge, and at 6 and 12 months follow-up. Cost outcomes are absenteeism, presenteeism, healthcare usage, and travelling costs. Cost-effectiveness will be evaluated from the societal and employer perspectives. The results obtained from this study will be useful for vocational rehabilitation practice and will provide stakeholders with relevant insights into two versions of vocational rehabilitation. Dutch Trial Register identifier: NTR4362 (registered 17 March 2014)