ASH: Bedtime Aspirin Lowers Blood Pressure

By Peggy Peck
NEW ORLEANS, 19 may 2008-- A low-dose aspirin taken at bedtime was associated with significant 24-hour reductions in blood pressure in a study of adults with prehypertension, researchers reported here.In a 244-patient trial, with a median age of 43, systolic blood pressure decreased by 5.6 mm Hg and diastolic by a mean of 3.7 mm Hg when the aspirin was taken at bedtime, said Ramón C. Hermida, Ph.D., of the University of Vigo in Spain, at the American Society of Hypertension meeting.But there was no benefit when 100 mg of aspirin was taken in the morning, Dr. Hermida added. The investigators recruited 244 patients with prehypertension (systolic of 120 to 139 mm Hg or diastolic of 80 to 89 mm Hg). Patients were randomized to lifestyle intervention (diet and exercise counseling), 100 mg of aspirin at awakening on top of lifestyle intervention, or 100 mg at bedtime on top of lifestyle intervention.Of the participants, 138 were women. An ambulatory monitoring device was used to sample blood pressure and heart rate every 20 minutes from 7 a.m. to 11 p.m. and every 30 minutes during nighttime hours for 48 hours, before treatment and after three months of treatment.
Compared with baseline values, patients who took aspirin at bedtime had a significantly greater nighttime dip in systolic blood pressure (P <0.05).
Awake, asleep, and 24-hour mean systolic pressures were significantly lower in the bedtime aspirin group than in the morning aspirin group or the lifestyle modification arm (P <0.001), he said.
Systolic blood pressure increases with age, which also increases the risk of stroke, but Dr. Hermida said it may be possible to slow that increase in systolic blood pressure with a low dose aspirin daily.
But daily aspirin therapy is not recommended for treatment of hypertension nor is it recommended in those as young as the population in this study, commented Sandra J. Talor, M.D., of the Mayo Clinic in Rochester, Minn., who was a discussant at a press conference where the study was discussed.
Dr. Talor, a member of the ASH board of directors, said that even though aspirin is generally well tolerated, it is not without risk. "Aside from the potential GI toxicity, we have no idea what the effect would be of long-term, daily aspirin therapy," she said.
For that reason she said the findings needed to be interpreted cautiously and should not direct clinical decisions.
The study was investigator initiated and funded. Dr. Hermida said he had no financial conflicts.

Primary source: American Society of Hypertension meetingSource reference:Hermida RC, et al "Ambulatory blood pressure reduction after bedtime administration in pre-hypertensive patients" ASH Meeting 2008; Abstract 227.