The morning blood pressure surge and all-cause mortality in patients referred for ambulatory blood pressure monitoring

BackgroundMorning blood pressure surge (MS) is accepted to increase cardiovascular risk, but it is not clear how it should be defined. Because dipping on 24-h ambulatory blood pressure monitoring (ABPM) associates with improved outcome we hypothesized that MS will not predict mortality independent of dipping.MethodsWe investigated a cohort of 2,627 patients referred for ABPM with available values for at least 1-h after awakening, and related them to all-cause mortality.ResultsDuring 22,353 person-years of follow-up, 246 patients died. We used Cox proportional hazards models to explore mortality associated with different definitions of the MS. Only the 1-h MS (difference between average blood pressure (BP) 1-h before and after awakening) was related to mortality: after multiple adjustments including 24-h systolic BP, those whose 1-h MS was above median (12 mmHg) had mortality hazard ratio (HR) of 0.61, 95% CI: 0.47-0.79, P <0.001. In predetermined subgroup analyses, nondippers (n = 1,039), had a highly significant MS-related decrease in mortality: HR 0.49, 95% CI: 0.34-0.73, P <0.001, unlike dippers (n = 1,588), HR = 0.90, 95% CI: 0.60-1.34.ConclusionAmong nondipping subjects referred for ABPM, the MS is associated with decreased mortality.