Blood Pressure Control in Adolescents With CKD and Risk of Kidney Failure in Young Adulthood

Abstract

Rationale & objective: Understanding risk factors for chronic kidney disease (CKD) progression during adolescence is essential to improve outcomes for these individuals as adults. The objective of the present study was to retrospectively analyze electronic health records of children with CKD to understand the effect of cumulative systolic blood pressure (SBP) load during adolescence on time to kidney replacement therapy (KRT) or death during young adulthood. Study design: Retrospective cohort study. Setting & participants: Adolescents with CKD were enrolled from 14 academic medical centers in the Preserving Kidney Function in Children with Chronic Kidney Disease (PRESERVE) study. Individuals aged between 1 and less than 18 years with 2 or more estimated glomerular filtration rate measurements between 30 and <90 mL/min/1.73 m2 separated by ≥90 days without an intervening estimated glomerular filtration rate ≥90 mL/min/1.73 m2 were included. Exposure: Cumulative SBP load was defined using area under and above the SBP curve (ie, time and magnitude) and time-only approaches using the 50th, 75th, and 90th SBP percentiles. Outcomes: Time to KRT (long-term dialysis initiation or kidney transplantation) or death were ascertained via linkage with the US Renal Data System. Analytical approach: Cox proportional hazards models were used to investigate the relationship between blood pressure (BP) control and the composite of KRT or death. Results: The cohort included 2,585 individuals with a median follow-up of 7.45 years (IQR, 6.05-9.20), among whom 4.6% (n = 118) met the KRT or death outcome between ages 18 and 30 years. In an adjusted Cox model, each unit increase (percentile point × time) in cumulative SBP load >90th percentile was associated with 1.36 (95% CI, 1.17-1.58) times higher hazard of KRT or death at age 18-19 years. Control of SBP to <90th percentile for 25%, 50%, and 100% of time between ages 14 and 18 years was associated with a 47%, 72%, and 92% risk reduction of KRT or death at age 18-19 years compared with no SBP control. Limitations: Misclassification of BP control related to white coat or masked hypertension. Adherence to prescribed antihypertensive medications was not assessed. Conclusions: Worse SBP control during adolescence was associated with a markedly increased risk of kidney failure in young adulthood. Cumulative SBP load derived from electronic health record data can inform risk of adverse long-term kidney outcomes.