Association of visit-to-visit blood pressure variability with kidney disease progression and cardiovascular outcomes in the chronic renal insufficiency cohort (CRIC).

BACKGROUND: Visit-to-visit variability (VVV) of blood pressure (BP) has been linked to adverse cardiovascular and kidney outcomes in various populations, but results in those with chronic kidney disease (CKD) have been inconsistent. METHODS: We evaluated VVV in Chronic Renal Insufficiency Cohort (CRIC) participants, using the coefficient of variation (CoV = standard deviation of SBP/mean SBP) calculated from BP measurements obtained at baseline visit through year 5 of the study. Cox proportional hazards models were used to assess the association of CoV with a composite cardiovascular outcome (myocardial infarction, stroke, peripheral artery disease, heart failure) and a composite kidney outcome (50% reduction in estimated glomerular filtration rate or end-stage kidney disease). RESULTS: Among 3891 participants (44% women, mean age 63 ± 10 years, mean CoV 10.3 ± 5.2%), 757 cardiovascular and 920 kidney events occurred during a median follow-up of 5.4 and 4.5 years, respectively. In unadjusted analyses, the upper tertile of CoV was associated with increased risk of both cardiovascular [hazard ratio 2.04, 95% confidence interval (CI) 1.70-2.43] and kidney outcomes (hazard ratio 1.62, 95% CI 1.38-1.89) compared to the lowest tertile. However, after adjustment for clinical and sociodemographic factors, higher CoV was significantly associated with cardiovascular outcomes (adjusted hazard ratio 1.25, 95% CI 1.04-1.52) but not kidney outcomes (adjusted hazard ratio 0.95, 95% CI 0.80-1.15). CONCLUSION: In this large CKD cohort, higher visit-to-visit BP variability was independently linked to adverse cardiovascular, but not kidney, outcomes.