Objectives: To determine patterns of within-day orthostatic blood pressure (BP) changes and clinical factors correlated with them in frail, elderly nursing home residents.
Design: Prevalence study of orthostatic BP change.
Setting: Sample of 45 nursing homes.
Participants: A total of 911 long-stay residents, aged 60 years or older, able to stand for at least 1 minute.
Main outcome measures: Supine and 1-minute and 3-minute standing BP measurements and heart rates, taken by a random-zero sphygmomanometer before and after breakfast and before and after lunch, symptoms upon standing, medication use, and clinical and functional assessments.
Results: Four orthostatic hypotension (OH) groups were defined based on the frequency of a 20 mm Hg or greater orthostatic BP decline during any of 8 postural change measures: no OH group (48.5%); isolated OH group (only once, 18.3%); variable OH group (2-3 times, 19.9%); and persistent OH group (> or =4 times, 13.3%). Orthostatic hypotension was most prevalent before breakfast, especially 1 minute after standing (21.3%), and least prevalent after lunch after 3 minutes of standing (4.9%) (P=.001). A regression approach to repeated measures analysis (method of general estimating equations) showed the following to be significantly associated with OH (P< or =.05): elevated supine systolic BP before breakfast, dizziness/light-headedness on standing, male sex, medication for Parkinson disease, time of day (particularly before breakfast), greater independence in activities of daily living, and low body mass index.
Conclusions: Orthostatic hypotension occurs in more than half of frail, elderly nursing home residents, but is highly variable over time. It is most prevalent in the morning when subjects first arise and when supine BP is highest. The relationship of OH with elevated BP, but not antihypertensive medication use, suggests that the treatment of hypertension may improve postural BP regulation.