Ambulatory blood pressure control with bedtime aspirin administration in subjects with prehypertension

Abstract

BackgroundAspirin has been found to prevent angiotensin II-induced hypertension and to induce nitric oxide (NO) release from vascular endothelium. Low-dose aspirin has also been shown to reduce blood pressure (BP) when administered at bedtime, as opposed to upon awakening, in untreated hypertensive patients and high-risk pregnant women. Accordingly, we investigated the effects on ambulatory BP of aspirin administered at different times of the day in prehypertension.MethodsWe studied 244 subjects with prehypertension, 43.0 13.0 years of age, randomly divided in three groups: nonpharmacological hygienic-dietary recommendations; the same recommendations and aspirin (100 mg/day) on awakening; or the same recommendations and aspirin at bedtime. BP was measured for 48 consecutive hours before and after 3 months of intervention.ResultsAmbulatory BP was unchanged in subjects randomized to either nonpharmacological intervention or aspirin on awakening. A significant ambulatory BP reduction was, however, observed in the subjects who received aspirin at bedtime (decrease of 6/3 mm Hg in the 24-h mean of systolic (SBP)/diastolic BP (DBP), respectively; P<0.001), without changes in heart rate (HR) from baseline. BP was homogenously controlled along the 24 h after bedtime aspirin administration (6/4 mm Hg reduction in activity mean of SBP/DBP; 6/3 mm Hg reduction in sleep-time mean, respectively).ConclusionsThis prospective trial documents a significant effect on BP of low dose aspirin only when ingested at bedtime by prehypertensive subjects. The timed administration of low-dose aspirin could thus provide a valuable and cost-effective approach for BP control in subjects at elevated risk of developing hypertension. © 2009 American Journal of Hypertension, Ltd.