Cardiovascular prognostic value of ambulatory blood pressure monitoring in a Portuguese hypertensive population followed up for 8.2 years.

AIM: We investigated the cardiovascular (CV) prognostic value of 24-h ambulatory blood pressure (ABP) and blood pressure (BP) during the six 4-h periods of the 24-h ABP length in a cohort of 1200 Portuguese hypertensive patients (aged 51±12 years) without earlier CV events.
METHOD: The presence of CV events were followed for 9.833 patient years and analyzed using a cox hazard model.
RESULTS: During the 15.2 (mean 8.2) years follow-up, there were 152 CV events (11% fatal) including 79 strokes and 52 coronary events. After adjustment for risk factors and office BP (OBP), a 1-standard deviation increment of 24-h, daytime and night-time systolic BP (SBP) significantly predicted any CV event with hazard ratios (HR) 1.41, 1.33 and 1.57, respectively, and stroke with HR 1.67, 1.58, 1.67, respectively (all P<0.01), but not coronary events. Prognostic significance of these SBP values and of night-time ABP persisted after adjustment for diastolic BP and daytime ABP, respectively, whereas the opposite did not occur. SBP night-time fall (%) inversely predicted total CV events after adjustment for diastolic BP night-time fall. Among all six 4-h periods of 24-h, increment of SBP during the first 4 h of night-time was the most powerful predictor of any CV event (HR 1.64) and stroke (HR 2.02) (both P<0.01) even after adjustment for daytime and 24-h BP.
CONCLUSION: In predicting CV events and stroke, ABP is superior to office BP, ABP systolic is superior to ABP diastolic, and night-time BP is superior to daytime BP particularly during the first 4 h of sleep.