Cumulative Blood Pressure Load and Incident CKD

Abstract

Rationale & Objective: The association of longterm cumulative blood pressure (BP) loads with the risk of incident chronic kidney disease (CKD) remains a matter of debate. This study investigated this association among healthy Korean adults with normal kidney function. Study Design: Prospective cohort study. Setting & Participants: We analyzed 5,221 participants without CKD in the Korean Genome and Epidemiology Study. Cumulative systolic and diastolic BP (SBP and DBP) loads were calculated as the ratios of the areas under the curve (AUC) for SBP >= 120 mm Hg or >= 80 mm Hg for DBP divided by the AUC for all SBP or DBP measurements during the exposure period. These AUCs were categorized into 4 groups: group 0 (reference), cumulative BP load of 0 and groups 1-3, tertiles of cumulative BP loads. Outcome: Primary end point was incident CKD defined as a composite of an estimated glomerular fi ltration rate (eGFR) below 60 mL/min/ 1.73 m2 or proteinuria greater than 1+ on dipstick examination for at least 2 consecutive measurements >= 90 days apart. Analytical Approach: Multivariable Cox proportional hazards regression to estimate the independent association of cumulative BP loads with incident CKD. Results: Higher cumulative SBP and DBP loads were associated with an increased risk of incident CKD (HR, 1.23 [95% CI, 1.12-1.35] for SBP; and HR, 1.14 [95% CI, 1.0 4-1.26] for DBP loads for each 1.0-unit greater load). Compared with SBP group 0, groups 2 and 3 were associated with 1.94- and 1.89-fold greater risk of incident CKD. Compared with DBP group 0, groups 2 and 3 were associated with 1.42- and 1.54-fold greater risks. These associations of high cumulative BP loads with an increased risk of incident CKD remained consistent even in the subgroups not taking antihypertensive agents or without prior hypertension diagnosis. Limitations: The assessment of CKD outcomes relied on eGFR and spot urine tests. Conclusions: These fi ndings highlight the association between high cumulative SBP and DBP loads and the occurrence of CKD, even in individuals with normal BP levels.