Feasibility of a Home-Based Exercise Program in Lung and Liver Transplant Recipients for Management of Post-Transplant Metabolic Syndrome: A Pilot Randomized Controlled Trial (Preprint)

BACKGROUND Post-transplant metabolic syndrome (PTMS) is a common contributor to morbidity and mortality in solid organ transplant recipients in the late post-transplant period (≥ 1-year). Patients diagnosed with PTMS are at higher risk of cardiovascular disease and frequently experience decreased physical function and health-related quality of life (HRQL). Studies in the early post-transplant period (< 1-year) have shown the benefits of facility-based exercise training on physical function and HRQL, but have not evaluated the effects on metabolic risk factors. It remains unclear whether home-based exercise programs are feasible and can be sustained with sufficient adherence and exercise dose to have effects on PTMS. This protocol outlines the methodology of a randomized controlled trial of a partly-supervised home-based exercise program in lung (LTx) and liver (OLT) transplant recipients. OBJECTIVE 1) To evaluate the feasibility (i.e. recruitment rate, program adherence, attrition, safety, and participant satisfaction) of a 12-week individualized, home-based aerobic and resistance training program in LTx and OLT recipients initiated 12 to 18 months post-transplant; and 2) to assess estimates of intervention efficacy on metabolic risk factors, self-efficacy for exercise, and HRQL. METHODS 20 LTx and 20 OLT recipients with two or more cardio-metabolic risk factors at 12-18 months post-transplant will be randomized to an intervention group (home-based exercise training) or a control group. The intervention group will receive an individualized exercise prescription comprising aerobic and resistance training 3-5 times per week for 12 weeks. Participants will meet with a qualified exercise professional weekly (via videoconference) to guide exercise progression, provide support, and promote exercise self-efficacy. Participants in both study groups will receive one counselling session on healthy eating with a dietitian at the beginning of the intervention. For the primary aim, feasibility will be assessed through recruitment rate, program adherence, satisfaction, attrition, and safety. Secondary outcomes will be measured at baseline and 12-weeks, and include assessments of metabolic risk factors (i.e. insulin resistance, abdominal obesity, blood pressure, and cholesterol), HRQL, and exercise self-efficacy. Descriptive statistics will be used to summarize program feasibility and effect estimates (means and 95% confidence interval) for sample size calculations in future trials. RESULTS Enrollment for this study started in July 2021. It is estimated that the study period will be 18 months with data collection completed by December 2022. CONCLUSIONS A partly-supervised home-based, individually tailored exercise program that promotes aerobic and resistance training and exercise self-efficacy may prove to be an important intervention for improving the metabolic profile of LTx and OLT recipients with cardio-metabolic risk factors. Thus, characterizing the feasibility and effect estimates of home-based exercise constitutes the first step in the development of future clinical trials designed to reduce the high morbidity associated with PTMS. CLINICALTRIAL https://clinicaltrials.gov/ct2/show/NCT04965142