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

<h2>Abstract</h2><h3>Rationale & Objective</h3> 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 current study was to retrospectively analyze electronic health records (EHR) of children with CKD to understand the effect of cumulative systolic blood pressure (SBP) load during adolescence on time to kidney replacement therapy or death during young adulthood. <h3>Study Design</h3> Retrospective cohort study <h3>Setting & Participants</h3> Adolescents with chronic kidney disease were enrolled from 14 academic medical centers in the Preserving Kidney Function in Children with Chronic Kidney Disease (PRESERVE) study. Individuals between the ages of 1 and <18 years with ≥2 eGFRs between 30 and <90 mL/min/1.73m² separated by ≥90 days without an intervening eGFR value ≥90 mL/min/1.73m² were included. <h3>Exposure</h3> Cumulative systolic blood pressure (SBP) load was defined using area under and above the SBP curve (i.e., time and magnitude), and time-only approaches using the 50th, 75th, and 90th SBP percentiles. <h3>Outcomes</h3> Time to kidney replacement therapy (KRT, chronic dialysis initiation or kidney transplantation) or death were ascertained via linkage with the United States Renal Data System. <h3>Analytical Approach</h3> Cox proportional hazards models were used to investigate the relationship between BP control and the composite of KRT or death. <h3>Results</h3> 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 18-30 years. In an adjusted Cox model, each unit increase (pp*time) in cumulative SBP load above the 90th percentile was associated with 1.36 (95% CI: 1.17, 1.58) times higher hazards of KRT or death between ages 18-19 years. SBP control to <90th percentile for 25%, 50%, and 100% of time between ages 14 to 18 years was associated with a 47%, 72%, and 92% risk reduction of KRT or death between ages 18 to 19 years compared to no SBP control. <h3>Limitations</h3> Misclassification of BP control related to white coat or masked hypertension. Adherence to prescribed anti-hypertensive medications was not assessed. <h3>Conclusions</h3> Worse SBP control during adolescence was associated with a markedly increased risk of kidney failure in young adulthood. Cumulative SBP load derived from EHR data can inform risk of adverse long-term kidney outcomes. <h3>Plain-Language Summary</h3> Chronic kidney disease is commonly accompanied by elevated blood pressure. Understanding risk factors for chronic kidney disease progression during adolescence is essential to improve outcomes for these individuals as adults. We used electronic health records to study the effect of systolic blood pressure load in adolescents with chronic kidney disease on risk of kidney failure in young adulthood. We found that worse systolic blood pressure control during adolescence is associated with a markedly increased risk of kidney failure in young adulthood. The study demonstrates that blood pressure readings from electronic health record data can be used to estimate the risk of adverse long-term kidney outcomes.