Boosting Exercise Adherence in Knee Osteoarthritis (BOOST-OA)

Background: Knee osteoarthritis (OA) is a leading cause of functional limitations among Veterans. Physical therapy (PT), with a focus on exercise, has strong evidence for improving physical function and other outcomes among individuals with knee OA. However, low adherence to home exercise is a major challenge both during the episode of care and following completion of therapy, significantly limiting the effectiveness of PT for knee OA. A recent systematic review highlighted the need for rigorous development and testing of interventions to enhance adherence to home exercise in the context of physical rehabilitation. In this project, we will test the effectiveness of a theoretically-informed, scalable intervention to enhance adherence to home exercise among Veterans receiving PT for knee OA. “Boosting Exercise Adherence in Knee Osteoarthritis” (BOOST-OA) includes components that address both exercise behavior initiation (conducted in conjunction with the PT episode of care) and maintenance (conducted after completion of PT care). Specifically, BOOST- OA includes: 1) Tools and activities woven into PT visits that address outcome expectations, action self- efficacy, goal-setting and monitoring (3-month behavior initiation phase) and 2) Health coaching calls that address satisfaction with outcomes, relapse prevention planning and independent monitoring (9-month behavior maintenance phase). Both phases will be supported by tailored messages through Annie, the VA’s text messaging service. The intervention will address strengthening and stretching exercises, as well as overall physical activity, as these are all part of a comprehensive approach to mitigating functional losses. Methods: We propose a pragmatic cluster-randomized trial, with 8 VA PT clinics randomized to BOOST-OA vs. usual PT care (UC). Participants will be Veterans with symptomatic knee OA (n=360, 45 per site). At BOOST- OA sites, physical therapy clinicians will deliver behavior initiation components in conjunction with standard PT visits, and a health coach will deliver maintenance components via telehealth. The primary outcome will be self-reported physical function, assessed via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function subscale. Secondary outcomes will include the Patient Specific Functional Scale, physical function tests (30-second chair stand, 2-minute step test), accelerometer-based physical activity, the Exercise Adherence Rating Scale, the WOMAC pain subscale, and the Self-Efficacy for Exercise scale. Follow- up assessments will be conducted after 3- months (end of behavior initiation phase), 12-months (end of intervention, primary time point), 18-months and 24-months (final durability time point). Specific aims are: Aim 1. Examine the effectiveness of BOOST-OA for improving physical function and other key outcomes among Veterans receiving outpatient PT for knee OA. We hypothesize that Veterans in BOOST- OA clinics will have clinically relevant improvements in WOMAC and other outcomes relative to the UC group. Aim 2. Explore patient characteristics associated with differential improvement following BOOST-OA. We will conduct a data-driven analysis to discover heterogeneity of treatment effects that will inform delivery BOOST-OA in VA clinical practice. Aim 3: Conduct qualitative analyses of Veteran and physical therapy clinician experiences with BOOST-OA to inform future implementation. We will conduct individual semi-structured interviews with Veterans and clinicians delivering BOOST-OA to understand acceptability, feasibility, and perceived efficacy of the program, as well as barriers and facilitators to program participation and implementation. Impacts: This project directly addresses the Rehabilitation Research Development & Translation goal of maximizing Veterans’ functional independence, as well as the priorities of the Durability of Rehabilitation Interventions for Veterans Notice of Special Interest. BOOST-OA co Project Number: 1I01RD000435-01A1 | Fiscal Year: 2026 | NIH Institute/Center: Veterans Affairs (VA) | Principal Investigator: Kelli Allen | Institution: DURHAM VA MEDICAL CENTER, DURHAM, NC | Activity Code: I01 | Study Section: Musculoskeletal Health & Function[RRD2] View on NIH RePORTER: https://reporter.nih.gov/project-details/11241465