Sarcopenia and its components in adult renal transplant recipients: prevalence and association with body adiposity

Sarcopenia is a progressive and generalised skeletal muscle disorder associated with adverse outcomes. Ageing causes primary sarcopenia, while secondary causes include chronic kidney disease (CKD), long-term use of glucocorticoids and obesity. The aim of the present study was to evaluate the prevalence of sarcopenia using guidelines recommended by the European Working Group on Sarcopenia in Older People (EWGSOP, 2010; EWGSOP2, 2018) and the Foundation of the National Institutes of Health (FNIH) and analyse the relationship between sarcopenia and body adiposity in adult renal transplant recipients (RTR). This was a cross-sectional study of adult RTR (BMI ≥ 18·5 kg/m2). Body composition was evaluated by dual-energy X-ray absorptiometry (DXA) and anthropometry. Glomerular filtration rate was estimated (eGFR) by CKD-Epidemiology Collaboration equation. The prevalence of sarcopenia in adult RTR (n 185; 57 % men, 50 (se 0·82) years and eGFR 55·80 (se 1·52) ml/min) was 7 % (FNIH), 11 % (EWGSOP2) and 17 % (EWGSOP). Low muscle mass, muscle function and physical performance affected, respectively, up to 28, 46 and 10 % of the participants. According to EWGSOP and EWGSOP2, body adiposity evaluated by anthropometry and DXA (percentage trunk fat) was lower in participants with sarcopenia. Conversely, according to the FNIH criteria, RTR with sarcopenia presented higher waist:height ratio. The present study suggests that adult RTR sarcopenia prevalence varies according to the diagnostic criteria; low muscle mass, low muscle function and low physical performance are common conditions; the association of body adiposity and sarcopenia depends on the criteria used to define this syndrome; and the FNIH criteria detected higher adiposity in individuals with sarcopenia.