Day-night dip and early-morning surge in blood pressure in hypertension: prognostic implications

We investigated the relationship between the day-night blood pressure (BP) dip and the early morning BP surge in an cohort of 3012 initially untreated subjects with essential hypertension. The day-night reduction in systolic BP showed a direct association with the sleep trough (r = 0.564; P < 0.0001) and the preawakening (r = 0.554; P < 0.0001) systolic BP surge. Over a mean follow-up period of 8.44 years, 268 subjects developed a major cardiovascular event (composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and heart failure requiring hospitalization) and 220 subjects died. In a Cox model, after adjustment for predictive covariates, including age, sex, diabetes mellitus, cigarette smoking, total cholesterol, left ventricular hypertrophy on ECG, estimated glomerular filtration rate, and average 24-hour systolic BP, a blunted sleep trough (≤ 19.5 mm Hg; quartile 1) and preawakening (≤ 9.5 mm Hg; quartile 1) BP surge was associated with an excess risk of events (hazard ratio, 1.66 95% CI, 1.14-2.42]; P = 0.009; hazard ratio, 1.71 95% CI, 1.12-2.71]; P = 0.013). After adjustment for the same covariates, neither the dipping pattern nor the measures of early morning BP surge were independent predictors of mortality. In conclusion, in initially untreated subjects with hypertension, a blunted day-night BP dip was associated with a blunted morning BP surge and vice versa. In these subjects, a blunted morning BP surge was an independent predictor of cardiovascular events, whereas an excessive BP surge did not portend an increased risk of events.