Magnitude of Hypotension Based on Office and Ambulatory Blood Pressure Monitoring: Results From a Cohort of 5066 Treated Hypertensive Patients Aged 80 Years and Older.

Background And Objective: Elderly patients can be particularly susceptible to the adverse effects of excessive blood pressure (BP) lowering by antihypertensive treatment. The identification of hypotension is thus especially important. Ambulatory BP monitoring (ABPM) is a more accurate technique than office for classifying BP status. This study examined the prevalence of hypotension and associated demographic and clinical factors among very old treated hypertensive patients undergoing ABPM.

Design, Setting, And Participants: Cross-sectional study in which 5066 patients aged 80 years and older with treated hypertension drawn from the Spanish ABPM Registry were included.

Measurements: Office BP and 24-hour ambulatory BP were determined using validated devices under standardized conditions. Based on previous studies, hypotension was defined as systolic/diastolic BP <110 and/or 70 mmHg with office measurement, <105 and/or 65 mmHg with daytime ABPM, <90 and/or 50 mmHg with nighttime ABPM, and <100 and/or 60 mmHg with 24-hour ABPM.

Results: Participants' mean age was 83.2 ± 3.1 years (64.4% women). Overall, 22.8% of patients had office hypotension, 33.7% daytime hypotension, 9.2% nighttime hypotension, and 20.5% 24-hour ABPM hypotension. Low diastolic BP values were responsible for 90% of cases of hypotension. In addition, 59.1% of the cases of hypotension detected by daytime ABPM did not correspond to hypotension according to office BP. The variables independently associated with office and ABPM hypotension were diabetes, coronary heart disease, and a higher number of antihypertensive medications.

Conclusions: One in 3 very elderly treated hypertensive patients attended in usual clinical practice were potentially at risk of having hypotension according to daytime ABPM. More than half of them had masked hypotension; that is, they were not identified if relying on office BP alone. Thus, ABPM could be especially helpful for identifying ambulatory hypotension and avoiding overtreatment, in particular, in patients with diabetes, heart disease, or on antihypertensive polytherapy.