Change in appendicular lean mass in patients established on peritoneal dialysis as measured by dual x-ray absorptiometry (DXA) scanning

Abstract

Background/objectives: Peritoneal dialysis (PD) patients are at increased risk of malnutrition and cachexia, definitions of which include weight loss. However, PD patients can absorb glucose from the dialysate and loss of muscle mass may be overlooked by fat weight gain. As such, we wished to review changes in body composition in prevalent PD patients. Subjects/methods: We compared changes in body composition measured by dual x-ray absorptiometry (DXA) in adult PD patients, and calculated glucose absorption based on 24-h collections of PD dialysate. Results: Overall, 73 prevalent PD patients, 60.3% male, mean age 62.5 ± 16.4 years, had DXA scans a median of 24 (15–27) months apart. Weight did not change (70.7 ± 16.8 vs. 70.9 ± 16.8 kg), with a median 198 (88–295) mmol glucose absorbed/day. Appendicular lean mass (ALM) decreased in most of the male (59%) and female (52%) patients, and the change in ALM was negatively associated with the change in percentage body fat mass (%BFM) r = −0.54, p < 0.001. Overall, 56 patients (76.7%) were admitted to hospital with intercurrent illnesses. Women who lost ALM and gained %BFM had more hospital admissions and those with an increase in %BFM had more admissions due to PD peritonitis while, in males, these outcomes were not seen. Conclusion: Although overall weight did not change, the majority of PD patients lost ALM, and this loss of muscle mass was masked by a gain in fat mass. Definitions of malnutrition and cachexia, which include unintentional weight loss criteria will underestimate the prevalence of PD patients with loss of muscle mass.