427 LATE MORNING HYPOTENSION: A COMMON, UNRECOGNIZED PHENOMENON IN HYPERTENSIVE PATIENTS LINKED TO TIGHTER BLOOD PRESSURE CONTROL, MULTIPLE DRUG THERAPY, OLDER AGE AND FEMALE GENDER

Objective: To identify potential excessive lowering of blood pressure (BP) in treated hypertensive subjects in the late morning hours, around the peak effect of many BP lowering agents consumed in the morning. Methods: Analysis of 24 ambulatory blood pressure monitoring (ABPM) of 556 consecutive referred hypertensive subjects. Hypotension was defined as systolic BP< 110 mmHg or ≥25% lower than the mean 3 first awake recordings provided that it was also < 85% of the mean 24 h systolic BP and occurred before 1200 h (to avoid the inclusion of lunch related post-prandial hypotension). Results: Late morning hypotension (LMH) was seen in only 6.4% (13/203) of untreated-, but in 17.85% (63/353) of treated hypertensive subjects. The mean number of hypotensive recordings was 2.07/patient, with a mean BP of 102/64, 101/61 and 99/58 mmHg on 3 consecutive measurements taken∼20 minutes apart. As compared with treated hypertensive patients free of hypotension, the drug-treated group with LMH was older (means: 64.78 yrs. +/− 2.2 vs. 56.5 +/−1.1 yrs; p < 0.01), included more females (67 % vs. 49%, p < 0.01), had lower achieved daytime BP (127/73 vs. 136/80 mmHg; p < 0.01) and received more morning antihypertensive agents (N = 1.7 vs 1.1; p < 0.0001). Conclusion: In an unselected cohort of subjects treated for hypertension, late morning systolic hypotension (∼100 mmHg) is surprisingly common (∼18%) and is sustained for ∼40 minutes. Hypotension is linked to older age, female gender and larger number of drugs consumed in the morning. The recognition of this phenomenon appears important for daily treatment of high blood pressure.