The prevalence of muscle wasting (sarcopenia) in peritoneal dialysis patients varies with ethnicity due to differences in muscle mass measured by bioimpedance

Background/objectives Sarcopenia is associated with increased mortality. European and North American recommended screening for low muscle mass uses gender specific cut points, with no adjustment for ethnicity. We wished to determine whether the prevalence of sarcopenia was altered by ethnicity in peritoneal dialysis (PD) patients. Subjects/methods We measured appendicular lean mass indexed to height (ALMI) in PD patients by segmental bioimpedance and determined sarcopenia using different cut off points for reduced muscle mass. Results We measured ALMI in 434 PD patients, 55.1% males, mean age 55.3 +/- 16.2 years, 32.3% diabetic, 54.1% white, 23.7% Asian, 19.1% black. ALMI was lower in Asian women, compared to white and black women (6.4 +/- 1.1 vs. 6.6 +/- 1.0 and 6.9 +/- 1.4 kg/m(2)), and lower in Asian men (7.5 +/- 1.3 vs. 8.5 +/- 1.2 and 8.7 +/- 1.3 kg/m(2)), p < 0.001. Depending on the ALM/ALMI cut point; the prevalence of sarcopenia was greater in Asian patients (25.6-41.2% using North American or European cut points) compared to white (12.3-18.7%) and black patients (3.8-15.7%), p < 0.001, but <11% when using Asian-specific cut points. The prevalence of sarcopenia obesity (BMI >= 30 kg/m(2)) was <3%, for all groups. There was no association with duration of PD, dialysis prescription, residual renal function or small solute clearances. Conclusions There is no universally agreed consensus definition for loss of muscle mass (sarcopenia) and current European and North American recommended cut points for screening are adjusted only for gender. As body composition differs also with age and ethnicity, then ideally cut points should be based on age, gender and ethnicity normative values.