#5042 ASSOCIATIONS BETWEEN SARCOPAENIA, CARDIOVASCULAR HEALTH AND HABITUAL PHYSICAL ACTIVITY IN PATIENTS ON HAEMODIALYSIS
Authors: Vadaszy Noemi , Adenwalla Sherna , Billany Roseanne E , March Daniel , Young Hannah , Smith Alice , Graham-Brown Matthew , Burton James 
Published: June 2023

Abstract

Background and Aims
Patients with end-stage kidney disease (ESKD) show skeletal muscle abnormalities such as sarcopenia (presence of low muscle mass, strength, and physical performance). Severe sarcopenia and its components are associated with poor clinical outcomes, decreased quality of life (QoL), and mortality. The direction of the relationships between sarcopenia and cardiovascular disease are less clear as are the impact of exercise interventions in patients with severe sarcopenia.

Method
This is a post-hoc analysis of the CYCLE-HD study, which was a randomised controlled trial assessing the effects of a 6-month structured intradialytic cycling intervention on cardiovascular health in those on haemodialysis. Presence of sarcopenia was established using the European Working Group of Sarcopenia in Older People (EWGSOP) definition. A cut off of &lt;17.5 kg/m2 in men and &lt;14.5 kg/m2 in women were used for fat free mass to establish muscle quantity using bioimpedance. The cut off of 15 seconds on the sit to stand 5 tests was used to establish muscle strength and a score of ≤8 on the short physical performance battery was used to assess physical performance. If all three criteria were met, severe sarcopenia was confirmed. Accelerometery assessed habitual physical activity (PA) and the general practice physical activity questionnaire assessed self-reported PA. Magnetic resonance imaging (MRI) measured left ventricular mass, pulse wave velocity, and global native T1 mapping (measure of myocardial fibrosis). Mann - Whitney U or unpaired t-tests explored differences in cardiac MRI, and physical activity (PA) outcomes between sarcopenic and non-sarcopenic patients. Linear regressions were used to investigate whether sarcopenia or its components predict cardiovascular health, and habitual PA outcomes cross-sectionally at baseline and following the 6-month programme of intradialytic exercise. Multinomial regressions were used to explore if sarcopenia or its components predicted self-reported PA.

Results
130 patients (57 [±15] years, 95 [73.08%] male) were included in the analysis of whom 65 patients underwent the intradialytic cycling intervention. 31 (23.85%) patients had severe sarcopenia. 107(82.31%) had low muscle mass, 92(70.77%) had low strength, and 48 (36.92%) had low physical performance. Severe sarcopenia was a significant predictor for self-reported PA status (p = .042, Pseudo R2 = 0.043) at baseline but not for any other outcomes. However, low muscle mass was a significant predictor for LV mass (p = .014, R2 = 0.04, Β = -6.76). Low muscle strength was a significant predictor for higher pulse wave velocity (p = .010, R2 = 0.056, Β = 2.57) and global native T1 (p = .001, R2 = 0.091, Β = 26.79). Low fat mass (p = .005, R2 = 0.07, Β = -2198.63) and physical performance were significant predictors for mean steps (p&lt;.001, R2 = 0.12, Β = -209.16). Baseline severe sarcopenia or its components were not predictors for cardiovascular or habitual PA changes following intradialytic exercise.

Conclusion
Severe sarcopenia was present in nearly quarter of the participants, but the majority showed at least one muscle health related abnormality (low muscle mass, strength or physical performance). These markers of sarcopenia showed associations with habitual PA and structural markers of cardiovascular disease. However, the presence of sarcopenia may not limit the benefits offered by intradialytic exercise. Patients with sarcopenic traits should be encouraged to participate in appropriate interventions to improve health and wellbeing.