Decreased Maximal Aerobic Capacity in Pediatric Chronic Kidney Disease

Adult and pediatric patients with ESRD have impaired maximum oxygen consumption (VO2 max), a reflection of the cardiopulmonary system's ability to meet increased metabolic demands. We sought to determine factors associated with decreased VO2 max in pediatric patients with different stages of CKD. VO2 max was measured using a standardized exercise testing protocol in patients with stage 2 to 4 chronic kidney disease (CKD) (n = 46), in renal transplant recipients (n = 22), in patients treated with maintenance hemodialysis (n = 12), and in age-matched healthy controls (n = 33). VO2 max was similar between children with stage 2 CKD and controls, whereas lower VO2 max was observed among children with stage 3 to 4 CKD, those treated with hemodialysis, and transplant recipients. In univariate analysis, VO2 max was significantly associated with body mass index, resting heart rate, C-reactive protein, serum triglycerides, serum creatinine, and measures of diastolic function; no significant associations with left ventricular structure or systolic function were identified. In multivariate regression analysis, patient category versus control and the presence of diastolic dysfunction were independent predictors of lower VO2 max. These results suggest that aerobic capacity is decreased in the early stages of CKD in children and that lower VO2 max can be predicted by the presence of diastolic dysfunction, even if systolic function is normal