Morning-to-evening change in home blood pressure as a predictor of fatal and nonfatal cardiovascular events.

Abstract

Objective: We investigated the morning-to-evening changes in home blood pressure (BP) in relation to the risk of fatal and nonfatal cardiovascular events.

Method: The study participants (≥18 years of age) were outpatients enrolled in the China Nationwide Ambulatory and Home Blood Pressure Registry. Home BP was measured at baseline for 7 consecutive days in the morning and evening five times consecutively, of which the first three readings were averaged for analysis. The morning-to-evening changes in home BP were calculated by subtracting the BP values in the morning from that in the evening.

Result: During a mean (±SD) follow-up of 4.9 (±2.6) years, 184 cardiovascular events occurred among the 5057 study participants. The mean morning-to-evening change in home SBP/DBP was -2.2 ± 8.1/-2.5 ± 4.5 mmHg. The age and sex-standardized incident rate was highest in quartile 1 of the changes in both SBP and DBP for fatal and nonfatal cardiovascular events, stroke (log-rank test, P  < 0.001). After adjustment for confounding factors, including the mean of morning and evening BP, the hazard ratios for patients in quartile 1 of the morning-to-evening change relative to the overall study participants reached statistical significance for SBP [1.39, 95% confidence interval (95% CI) 1.03-1.88] and DBP (1.59, 95% CI: 1.17-2.15) in relation to fatal and nonfatal stroke, and for diastolic BP in relation to fatal and nonfatal cardiovascular events (1.42, 95% CI: 1.13-1.77).

Conclusion: In outpatients, a mild to moderate BP drop from morning to evening was associated with a significantly higher risk of all cardiovascular events, especially stroke.