MO1007RELATIONSHIP BETWEEN DIALYSIS ADEQUACY, ULTRAFILTRATION RATE AND SURVIVAL IN YOUNG HEMODIALYSIS (HD) PATIENTS HAVING INITIATED CHRONIC HD IN CHILDHOOD*

Abstract

Abstract Background and Aims Hemodialysis (HD) adequacy is currently assessed based on weight-normalized small solute clearance (spKt/V), with same targets in both adult and pediatric patients on chronic thrice weekly hemodialysis, despite lack of pediatric studies to support this. It has been hypothesised that pediatric patients of small size may require higher spKt/V targets, due to higher ratio of body surface area (BSA) to body weight and/or greater post-dialysis urea rebound. Ultrafiltration rates (UFR) >10-13 mL/kg/h, associated with increased mortality in adults, are furthermore routinely exceeded in pediatric patients with uncertain consequences. We aimed to characterize how different delivered HD adequacy metrics and UFR are associated with survival in a large cohort of patients who started HD in childhood. Method Retrospective analysis on a cohort of patients <30y on chronic HD since childhood (<19y), having received thrice-weekly HD 2004-2016 in outpatient DaVita dialysis centers. Mean delivered dialysis dose (spKt/V) and alternative measures of HD adequacy and fluid balance, including eKt/V, body-surface normalized Kt (Kt/BSA) and ultrafiltration rate (UFR), were investigated as predictors of survival in a Weibull regression model. Results A total of 1780 patients were included (age at initiation of HD: 0-12y: n=321, >12-18y: n=1459), with median spKtV=1.55, eKt/V=1.31, Kt/BSA=31.2 L/m2 and UFR=10.6 mL/kg/h. Kt/BSA was a better predictor of survival than spKt/V or eKt/V (P<0.001 versus P=0.002, respectively). UFR was associated with survival (P<0.001), with increased mortality <10/>18 mL/kg/h. Associations remained significant after adjusting for age, ethnicity, and etiology of kidney disease. Conclusion We found that targeting Kt/BSA>30 L/m2 in children and young adults on maintenance HD is associated with improved long-term outcomes, corresponding to spKt/V>1.4 (>12 years) and >1.6 (<12 years), respectively. Relatively high UFR of 10-18 ml/kg/h appears to be risk-free in this HD population.