Integrating estimated glomerular filtration rate and kidney replacement therapy criteria within the definition of kidney failure.

INTRODUCTION Guidelines define kidney failure based on initiation of maintenance kidney replacement therapy (KRT) or estimated glomerular filtration rate (eGFR) below 15 ml/min per 1.73 m2 for over 90 days, but most kidney failure registries track the incidence and outcomes of people who receive KRT only. The population burden of kidney failure and outcomes of patients identified by eGFR criteria remain understudied. METHODS Using population-based datasets from Alberta, Canada, we studied adults who initiated KRT or had incident kidney failure defined by KRT or eGFR criteria between April 2008 and March 2019. Individuals who met eGFR criteria for kidney failure were followed from cohort entry until death, initiation of KRT, or censoring (outmigration or March 31, 2021) to estimate the five-year risks of KRT initiation and death without receiving KRT and the rates of acute care utilization during follow-up. RESULTS The annual incidence was 212 per million population for KRT versus 293 for kidney failure, with larger incidence differences between KRT and kidney failure in older age and females. Among the 9691 incident kidney failure cases, 6216 (64.1%) were first identified by eGFR criteria. Within five years of meeting eGFR criteria, 34.0% died without receiving KRT. Females were less likely to receive KRT, more likely to die without receiving KRT, and had higher acute care use. CONCLUSIONS KRT registries may capture only one-third of incident kidney failure cases, inaccurately record the timing of disease onset, and under-represent older adults and females who have worse outcomes. Incorporating eGFR measurements to expand kidney failure data collection initiatives can potentially improve early disease identification, equity of healthcare planning, and outcome reporting for all affected individuals.