Visit-to-visit variability of blood pressure and cardiovascular disease and all-cause mortality: a systematic review and meta-analysis.
BACKGROUND Visit-to-visit blood pressure variability (BPV) has been shown to be a prognostic indicator in hypertensive patients. We designed this study to clarify the impacts of clinic and ambulatory BPV in predicting cardiovascular disease (CVD). METHODS We performed ambulatory BP monitoring (ABPM) in 457 hypertensive patients. Visit-to-visit BPV and ambulatory BPV were calculated as the SDs of clinic BP, awake BP, and sleep BP. The mean age of the subjects was 67.0 ± 9.2 years, and they were followed for 67 ± 26 months. Stroke, myocardial infarction, and sudden cardiac death were defined as Hard CVD events, and these plus angina, heart failure, and other CVDs were defined as All CVD events. Multivariable Cox hazard regression models predicting CVD events were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI) for different measures of BPV with adjustment for significant covariates. RESULTS In multivariable analyses, the BPV of clinic systolic BP (SBP) was an independent predictor for All CVD events (HR, 2.20; 95% CI, 1.25-3.88; P < 0.01), but not for Hard CVD events (P = 0.20). On the other hand, the BPV of sleep SBP was an independent predictor for Hard CVD events (HR, 2.21; 95% CI, 1.08-4.53; P = 0.03), but not for All CVD events (P = 0.88). Diastolic BPV exhibited the same pattern. CONCLUSIONS These findings suggest that visit-to-visit BPV and ambulatory BPV are separately useful in predicting cardiovascular outcomes.