MO590: A Home-Based Exercise and Physical Activity Intervention After Kidney Transplantation: Impact of Exercise Intensity. The Phoenix-Kidney Study Protocol
Authors: Vandecruys Marieke , De Smet Stefan , Cornelissen Véronique , Raes Jeroen , De Geest Sabina , Naesens Maarten , Leunis Sofie , De Beir Jasmine , Vanden Wyngaert Karsten , Nagler Evi , Glorieux Griet , Van Biesen Wim , Calders Patrick , Monbaliu Diethard , Van Craenenbroeck Amaryllis 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Advances in the field of kidney transplantation have led to improved postoperative survival rates, but age-standardized mortality nonetheless remains 2- to 7-fold higher in kidney transplant recipients—with cardiovascular disease representing the leading cause of death in recipients with a functioning graft. Poor physical fitness, not completely recovering after transplantation, adds to the heightened cardiovascular risk of hypertension, diabetes, dyslipidemia and obesity. So does the post-transplant continuation of gut microbial dysbiosis, which recently emerged as a modulator of muscular, metabolic and cardiovascular health. Exercise-based rehabilitation and physical activity interventions may prove pivotal in the care of kidney transplant recipients to address aforementioned outcomes.

METHOD
At 3 months post-transplant, a probability sample of 147 adult kidney transplant recipients from two independent Belgian transplant centers will be randomly allocated to either 6 months of home-based moderate-intensity training (MIT, n = 49), concurrent moderate- and high-intensity training (MHIT, n = 49) or usual care (CON, n = 49) (Figure1). High-intensity training sessions in MHIT are based on the Scandinavian model (four blocks of 4 min at high intensity interspersed by 3 min of active recovery), performed twice a week, and of equivalent energy expenditure as moderate-intensity training (Figure2). MIT and MHIT will perform similar muscle strengthening exercises, twice a week. The training intervention will be followed by an individualized activity intervention aiming for long-term physical activity maintenance in MIT and MHIT; using motivational interviewing techniques, co-creation of an action plan adapted to the patients’ preferences, goal-setting, gradually decreasing follow-up prompts over time and self-monitoring of physical activity behavior. Study participants will be followed-up till 2 years after transplantation. We hypothesize that the study intervention will improve our primary outcome cardiorespiratory fitness, assessed as peak oxygen uptake, at 9 months post-transplant. Secondary outcomes include muscle fitness, motor fitness, body composition, cardiovascular health, gut microbiome characteristics, health-related quality of life, safety, cost-effectiveness and implementation outcomes (Figure1). The role of training intensity and the role of baseline gut microbiome characteristics as predictor of individuals’ training response will be explored.

RESULTS
Results from this two-phased RCT will provide novel insights in the safety, implementation potential, cost-effectiveness and effectiveness of a home-based exercise program and physical activity intervention in de novo kidney transplant recipients to improve physical fitness, cardiovascular health, gut microbiome characteristics and health-related quality of life.

CONCLUSION
PHOENIX-kidney represents the first adequately powered multicenter RCT evaluating basic, clinical and health-economic outcome parameters in response to an exercise training and physical activity intervention in kidney transplant recipients.