Cumulative Blood Pressure Load and Incident CKD.

Rationale & objective: The association of long-term 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≥120mm Hg or≥80mm 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 filtration rate (eGFR) below 60mL/min/1.73m² 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, 1.04-1.26] 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 findings highlight the association between high cumulative SBP and DBP loads and the occurrence of CKD, even in individuals with normal BP levels.

Plain-language summary: Although hypertension is a major risk factor for chronic kidney disease (CKD), most studies have focused on single-point blood pressure (BP) measurements. To explore the association between long-term cumulative BP load and the development of CKD, 5,221 Korean adults with normal kidney function were included in this study. Cumulative systolic BP and diastolic BP load both exhibited a significant association with an increased risk of incident CKD. Notably, the association of cumulative BP loads with elevated risk of incident CKD was evident also in individuals who were not taking antihypertensive agents or who had no previous history of hypertension. These findings underscore the importance of managing long-term exposure to high BP, even in individuals with normal BP levels.