Screening for muscle loss in patients established on peritoneal dialysis using bioimpedance

Background/objectivesKidney dialysis patients with sarcopenia have increased mortality. Screening for low muscle mass may allow interventions at an earlier stage to help improve outcomes. We wished to determine the prevalence of low muscle mass in a cohort of peritoneal dialysis (PD) patients.Subjects/methodsWe measured lean body mass index (LBMI) in 490 PD patients by bioimpedance, grading patients using two different classifications of sarcopenia.

LBMI was 9.7±1.9 kg/m², mean age was 55.3±16.4 years, 53.1% were male, 33.7% were diabetic and 51% were Caucasoid. 98.5% of patients were classified as having sarcopenia based on LBMI cutoffs from NHANES data, whereas 28.8% had moderate and 6.3% severe sarcopenia using a grading correlated with functional disability. Lower muscle mass was associated with increasing co-morbidity (β=0.34, P=0.02) and age (β=0.01, P=0.006), and negatively with body mass index (β=-0.23, P<0.001), log serum creatinine (β=-0.231, P<0.001), normalised protein nitrogen appearance (β=-1.33, P<0.001) and log urine volume (β=-0.28, P=0.002). There was no association with duration of PD, dialysis prescription, residual renal function or solute clearances.

There is currently no agreed universal definition for sarcopenia, and prevalence varied markedly depending on the scoring system. Prevalence was not associated with small solute clearances, but was associated with sex, age co-morbidity, BMI and ethnicity. There was an association with dietary protein intake and urine volume, which may allow for dietary interventions and strategies to preserve urine output to reduce muscle loss in PD patients.