Prognostic influence of office and ambulatory blood pressures in resistant hypertension.

BACKGROUND: The prognostic value of office and ambulatory blood pressures (BPs) in patients with resistant hypertension is uncertain.
METHODS: This prospective study investigates the importance of office and ambulatory BPs as predictors of cardiovascular morbidity and mortality. At baseline, 556 resistant hypertensive patients underwent clinical-laboratory and 24-hour ambulatory BP monitoring examinations. Primary end points were a composite of fatal and nonfatal cardiovascular events and all-cause and cardiovascular mortalities. Multiple Cox regression was used to assess associations between BP and subsequent end points.
RESULTS: After median follow-up of 4.8 years, 109 patients (19.6%) reached the primary end point, and 70 all-cause deaths (12.6%) occurred (46 had cardiovascular causes). After adjustment for age, sex, body mass index, diabetes mellitus, smoking, physical inactivity, dyslipidemia, previous cardiovascular diseases, serum creatinine level, and number of antihypertensive drugs in use, no office BP showed any prognostic value. After further adjustment for office BP, higher mean ambulatory BPs were independent predictors of the composite end point. The hazard ratios associated with a 1-SD increment in daytime and nighttime systolic BP were 1.26 (95% confidence interval, 1.04-1.53) and 1.38 (1.13-1.68), respectively; the corresponding values for diastolic BP were 1.31 (1.05-1.63) and 1.36 (1.10-1.69). Ambulatory systolic and diastolic BP were equivalent predictors, and both were better than pulse pressure; nighttime BP was superior to daytime BP. For all-cause mortality, only the ambulatory BP monitoring diagnosis of true resistant hypertension was an independent predictor.
CONCLUSION: Higher ambulatory BP predicts cardiovascular morbidity and mortality in resistant hypertensive patients, whereas office BP has no prognostic value.