Study protocol for a multicentre randomized controlled trial on effectiveness of an outpatient multimodal rehabilitation program for adolescents with chronic musculoskeletal pain (2B Active)

Background: Chronic musculoskeletal pain (CMP) in adolescents can influence functioning and well-being, and has negative consequences for families and society as well. According to the Fear Avoidance Model, fear of movement and pain catastrophizing can influence the occurrence and maintenance of chronic pain complaints and functional disability. Primary objective is to evaluate the effectiveness of a multimodal rehabilitation program in reducing functional disability for adolescents with CMP compared with care as usual. Methods/Design: Pragmatic multicentre parallel group randomized controlled trial. Randomization by minimization (ratio 1: 1) and treatment allocation will be concealed, computer-generated and performed by an independent organization. After randomization, data collection and researchers remain blinded. Inclusion of 124 adolescents and their parents is intended. This sample size is based on a 25 % difference in group mean on the primary outcome, with a = 5 %, beta = 80 % and expected 15 % loss to follow up. Study population are adolescents (12-21 years) with CMP with an indication for outpatient rehabilitation treatment in the Netherlands. The intervention group receives a Multimodal Rehabilitation Program (MRP), a multidisciplinary outpatient individual rehabilitation program. MRP consists of 2 different treatment approaches: A graded exposure module or a combination module of graded exposure and physical training. Selection of a module depends on the needs of the patient. To both modules a parent module is added. The control group receives care as usual, which is the care currently provided in Dutch rehabilitation centres. Treatment duration varies between 7 and 16 weeks, depending on treatment allocation. Self-reported measurements are at baseline, and at 2, 4, 10 and 12 months after start of treatment. Intention to treat analysis for between group differences on all outcome variables will be performed. Primary outcome is functional disability (Functional Disability Inventory). Secondary outcome variables are fear of pain, catastrophizing, perceived harmfulness, pain intensity, depressive symptoms, and quality of life. Total direct and indirect costs and health related quality of life will be measured. Process evaluation focuses on protocol adherence, patient centeredness and treatment expectations. Discussion: A pragmatic approach was chosen, to ensure that results obtained are most applicable to daily practice.