Orthostasis in Alzheimer disease: a retrospective analysis

Vitiello et al. (1993) recently reported statistically significant decreases in systolic blood pressure upon standing in patients with Alzheimer disease (AD) (n = 60) as compared with healthy elderly controls (n = 20), which would suggest a possible autonomic dysfunction associated with AD. To investigate this issue, we conducted a retrospective analysis of blood pressures and heart rates of 31 patients 55-85 years of age (mean 69.6) who met National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer Disease and Related Disorders Association criteria for probable AD. The patients were selected from a pool of placebo-treated patients with AD in five inpatient phase I clinical trials. All patients met rigorous entrance criteria and thus were in excellent physical health except for AD. Blood pressure and pulse were assessed after 3-5 min of lying down and after 1-3 min of standing. Systolic and diastolic blood pressures showed decreases upon standing of 12 mm Hg (8.6%) and 6 mm Hg (8.2%), respectively, on day 1 and decreases of 10 mm Hg (7.6%) and 4 mm Hg (5.7%), respectively, on day 7 of hospitalization (p < 0.05). Pulse rates increased upon standing by 17% and 13% on days 1 and 7, respectively (p < 0.05). Our data support the finding of Vitiello et al. of significant postural decreases in systolic blood pressure in patients with AD. Well-controlled, prospective studies of orthostasis in AD and healthy elderly subjects should be conducted to determine its prevalence in both populations and to determine whether the orthostatic changes seen in AD differ from those in normal aging.