Estimated GFR at Dialysis Initiation and Mortality in Children and Adolescents.

RATIONALE & OBJECTIVE: The association of estimated glomerular filtration rate (eGFR) at dialysis therapy initiation with mortality among adult dialysis patients has been greatly debated, with some studies showing no benefit from early dialysis therapy initiation. However, this association has not been well investigated in pediatric dialysis patients. The objective of this study was to evaluate the mortality risk associated with eGFR at dialysis therapy initiation in children and adolescents with kidney failure. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 9,963 incident dialysis patients aged 1 to 17 years in the US Renal Data System registry (1995-2016). PREDICTOR: eGFRs at dialysis therapy initiation calculated using the pediatric-specific bedside Schwartz equation (<5, 5-<7, 7-<9, 9-<12, and ≥12mL/min/1.73m2). OUTCOME: Time to all-cause death. ANALYTICAL APPROACH: Cox proportional hazards regression adjusted for case-mix variables, height, body mass index, hemoglobin level, and serum albumin level. RESULTS: Median eGFR was 7.8 (IQR, 5.6-10.5) mL/min/1.73m2 and median age was 13 (IQR, 9-16) years. 696 deaths were observed during the median follow-up of 1.4 (IQR, 0.7-2.7) years, and overall crude mortality rate was 31 per 1,000 patient-years. There appeared to be a trend toward higher mortality risk across higher eGFRs at dialysis therapy initiation. Compared with eGFRs of 7 to <9mL/min/1.73m2, eGFRs <5 and ≥12mL/min/1.73m2 were associated with lower and higher mortality, with adjusted HRs of 0.57 (95% CI, 0.43-0.74) and 1.31 (95% CI, 1.05-1.65), respectively. In age-stratified analysis, there were consistent relationships among patients 6 years and older while the eGFR-mortality association was attenuated among patients younger than 6 years (Pinteraction = 0.002). LIMITATIONS: Possible errors in eGFRs due to methods for serum creatinine measurement. Unmeasured confounders related to eGFR at dialysis therapy initiation. CONCLUSIONS: Higher eGFR at dialysis therapy initiation was associated with higher mortality risk. Further studies of eGFR at initiation are needed in pediatric dialysis patients, especially among those younger than 6 years.