Relationship Between Visit-to-Visit Blood Pressure Variability (BPV) and Kidney Function in Patients with Hypertension

Background/Aims: To investigate the impact of kidney function (using estimated glomerular filtration rate, [eGFR]) on blood pressure variability (BPV) via a retrospective post hoc analysis of patients with hypertension enrolled in two large clinical trials. Methods: Subject-level data were extracted from ASCOT (N=18,852) and ALLHAT (N=26,441) databases; both were randomized, active controlled studies, with treatment duration for hypertension ≥4 years. Visit-to-visit BPV was assessed using the square root of the coefficient of variation of systolic blood pressure (SBP) across visits from 12 weeks onwards. Baseline GFR, estimated by the simplified Modification of Diet in Renal Disease equation, was stratified into ≤60, 61-90, and >90 mL/min/1.73 m2. The relationship between baseline eGFR and systolic BPV was analyzed using an analysis of covariance, with baseline factors considered as covariates. Studies were pooled and analyzed individually. Results: Patient characteristics were largely consistent between studies. In the pooled population (n=38,133) there were 19.1%, 62.9%, and 18.0% patients, with eGFR ≤60, 61-90, and > 90 mL/min/1.73 m2, respectively. Patients with lower baseline eGFR had higher systolic BPV, in the pooled population and the individual analyses. Other baseline predictors of high systolic BPV included high SBP and age, being male, and a smoker. An amlodipine-based regimen was a negative predictor of high systolic BPV, vs. other antihypertensives, regardless of eGFR. Conclusions: Patients with declining renal function tended to have higher systolic BPV vs. those without, even after adjusting for risk factors. Amlodipine-based therapy reduced BPV more than other antihypertensive agents, regardless of level of eGFR.