Intraindividual variability in orthostatic blood pressure changes among older adults: the influence of meals.

OBJECTIVES: To examine the influence of time of day and of meals on postural blood pressure (BP) changes in older adults.

DESIGN: Prevalence study of BP changes in response to orthostasis.

SETTING: A geriatric short-stay department

PARTICIPANTS: A total of 126 inpatients (91 women and 35 men; mean age: 81.4+/-7.9, range 61-95 years) were included in the study.

MEASUREMENTS: Two sets of BP and heart rate measurements were obtained for each subject by one examiner using a standard mercury manometer: (1) in mid-morning (between 10:00 and 10:30 a.m.) and (2) within 30 to 60 minutes after lunch (between 1:00 and 1:30 p.m.). Orthostatic hypotension (OH) was defined as a systolic blood pressure (SBP) decline > or = 20 mm Hg within 3 minutes after standing.

RESULTS: Sixty-one participants (48%) experienced significant orthostatic BP decline on at least one reading. Among them, 46 (37%) had OH in the mid-morning, and 32 (25%) had OH after lunch (P = .05). Only 17 (13%) had OH on both readings (persistent OH). Forty-four patients (35%) had variable OH. Patients with persistent OH were more likely to exhibit symptoms of dizziness and had a lower body mass index and a higher mean basal supine SBP. There was a positive correlation between basal supine SBP and postural SBP decline.

CONCLUSIONS: Because of the variability of postural BP changes, the diagnosis of OH should not be based on a single orthostatic BP measurement but requires repeated testing, at best under circumstances similar to those in which the symptoms occurred. The postprandial period is not particularly favorable to OH, suggesting that the ingestion of a meal does not worsen orthostatic BP changes in most aged patients.