MO590: A Home-Based Exercise and Physical Activity Intervention After Kidney Transplantation: Impact of Exercise Intensity. The Phoenix-Kidney Study Protocol

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.

Home-based exercise and PHysical activity maintenance interventiOn after livEr traNsplantation: Impact of eXercise intensity (PHOENIX-Liver)

Liver transplant recipients experience comorbidities, including impaired physical fitness, which could be managed by exercise and physical activity interventions. This study aims to evaluate the feasibility, clinical effectiveness and cost-effectiveness of a 6-month exercise intervention, followed by a 15-month tailored physical activity maintenance intervention, in de novo liver transplant recipients. This single-centre, randomised, controlled, single-blinded trial will recruit 147 adult liver transplant recipients at 3-5 months post-transplant. Participants will be randomised into (1) 6 months of enhanced usual care, not followed by a physical activity intervention (control (CON) group, n=49), (2) 6 months of moderate-intensity exercise training, followed by a physical activity intervention (moderate-intensity training (MIT) group; n=49) or (3) consecutively 3 months of moderate-intensity exercise training, 3 months of high-intensity interval training and a physical activity intervention (moderate and high-intensity training (MHIT) group; n=49). Exercise training will consist of home-based stationary bicycling and muscle-strengthening exercises, partially supervised by participants' local physiotherapists. The physical activity intervention includes an array of behaviour change techniques. Primary hypothesis: after the exercise intervention, peak oxygen uptake (V̇O2peak) will be higher in MHIT versus CON (α-level 0.05). Secondary hypotheses: after the exercise intervention, V̇O2peak will be higher in MIT versus CON and MHIT versus MIT (α-level 0.025). Secondary outcomes, assessed up to 2 years post-transplant, include physical fitness, cardiovascular and graft health, quality of life, physical activity and implementation outcomes. Trial registration number NCT06302205.

Sarcopenia in end-stage liver disease and after liver transplantation

Sarcopenia occurs in 30-70% of patients with end-stage liver disease and is associated with inferior pre- and post-liver transplant outcomes such as prolonged intubation times, long intensive care and hospitalization times, heightened risk of post-transplant infection, reduced health-related quality of life, and increased rates of mortality. The pathogenesis of sarcopenia is multifactorial and involves biochemical disturbances such as hyperammonemia, low serum concentrations of branched-chain amino acids (BCAAs) and low serum levels of testosterone, as well as chronic inflammation, inadequate nutritional status, and physical inactivity. Prompt recognition and accurate assessment of sarcopenia are critical and require imaging, dynamometry, and physical performance testing for the assessment of its subcomponents: muscle mass, muscle strength, and muscle function, respectively. Liver transplantation mostly fails to reverse sarcopenia in sarcopenic patients. In fact, some patients develop de novo sarcopenia after undergoing liver transplantation. The recommended treatment of sarcopenia is multimodal and includes a combination of exercise therapy and complementary nutritional interventions. Additionally, new pharmacological agents (e.g. myostatin inhibitors, testosterone supplements, and ammonia-lowering therapy) are under investigation in preclinical studies. Here, we present a narrative review of the definition, assessment, and management of sarcopenia in patients with end-stage liver disease prior to and after liver transplantation.

Revitalizing the Gut Microbiome in Chronic Kidney Disease: A Comprehensive Exploration of the Therapeutic Potential of Physical Activity

Both physical inactivity and disruptions in the gut microbiome appear to be prevalent in patients with chronic kidney disease (CKD). Engaging in physical activity could present a novel nonpharmacological strategy for enhancing the gut microbiome and mitigating the adverse effects associated with microbial dysbiosis in individuals with CKD. This narrative review explores the underlying mechanisms through which physical activity may favorably modulate microbial health, either through direct impact on the gut or through interorgan crosstalk. Also, the development of microbial dysbiosis and its interplay with physical inactivity in patients with CKD are discussed. Mechanisms and interventions through which physical activity may restore gut homeostasis in individuals with CKD are explored.

Physical Exercise After Solid Organ Transplantation: A Cautionary Tale

An increasing body of randomized controlled trials suggests the safety of engaging in moderate to vigorous intensity exercise training following solid organ transplantation. Fueled by emerging sport events designed for transplant recipients and the ever-growing body of research highlighting the diverse health benefits of physical activity, transplant recipients are now increasingly participating in strenuous and occasionally competitive physical endeavors that largely surpass those evaluated in controlled research settings. This viewpoint article adopts a cautionary stance to counterbalance the prevalent one-sided optimistic perspective regarding posttransplant physical activity. While discussing methodological limitations, we explore plausible adverse impacts on the cardiovascular, immunological, and musculoskeletal systems. We also examine the physiological consequences of exercising in the heat, at high altitude, and in areas with high air pollution. Risks associated with employing performance-enhancing strategies and the conceivable psychological implications regarding physical activity as a tribute to the 'gift of life' are discussed. With a deliberate focus on the potential adverse outcomes of strenuous posttransplant physical activity, this viewpoint aims to restore a balanced dialogue on our comprehension of both beneficial and potentially detrimental outcomes of physical activity that ultimately underscores the imperative of well-informed decision-making and tailored exercise regimens in the realm of posttransplant care.