Prevalence of and associations with reduced exercise capacity in peritoneal dialysis patients

Background: Exercise capacity is reduced in patients with end-stage renal disease on maintenance home peritoneal dialysis therapy, although the potential mechanisms and clinical implications remain unclear. Study Design: Cross-sectional study. Setting & Participants: 95 ambulatory prevalent and incident peritoneal dialysis patients in a well-established renal dialysis center (mean age, 58.26 ± 12.6 [SD] years; 63% men; mean duration of peritoneal dialysis therapy, 3.2 ± 4.1 years). Predictor: Estimated volume status using spectral bioelectrical impedance, echocardiography-derived hemodynamic parameters. Outcome: Exercise capacity measured as peak oxygen consumption using symptom-limiting treadmill exercise testing. Results: Exercise capacity was reduced in 96% of patients and severely reduced in 65%. Extracellular to intracellular fluid volume ratio showed the strongest correlation with reduced exercise capacity (R = -0.63; P < 0.001) and was superior to age, pulmonary capillary wedge pressure (E:E′ ratio), lean tissue mass index, and hemoglobin and albumin levels in predicting exercise intolerance. Limitations: Relatively small sample size and echocardiogram that was performed only at rest. Conclusions: There was a strong relationship between body extracellular to intracellular fluid volume ratio and exercise capacity in peritoneal dialysis patients. These findings provide new evidence for a connection between fluid distribution, muscle mass, and exercise capacity. Therapeutic strategies targeting fluid status and muscle mass may improve the exercise capacity of patients on peritoneal dialysis therapy.