Relationship between orthostatic hypotension and cognitive impairment in the elderly

Background and purpose: To determine the relationship between orthostatic hypotension (OH) and cognitive function in elderly subjects with memory complaints.

Methods: We studied the association between cognitive function and OH in 495 consecutive elderly outpatients attending a memory centre. Blood pressure (BP) was measured in a sitting and standing position. We examined cognitive function using a validated comprehensive battery of neuropsychological tests, the cognitive efficiency profile (CEP) assessing the main cognitive areas. Subjects were classified into 4 categories according to their cognitive status: normal cognitive function, mild cognitive impairment (MCI), Alzheimer's disease (AD) or vascular dementia (VaD).

Results: In this population, 76±8 years of age (women 72%), 18% had normal cognitive function, 28% had MCI, 47% AD, and 7% VaD. Hypertension was observed in 74% of patients. OH was present in 14% of subjects (n=69). After adjustment for age, education level, systolic BP, diastolic BP, weight, and antihypertensive drugs, subjects with OH had worse cognitive function than those without OH (CEP score 50±24 vs 56±22, p<0.05). Moreover, a significant relationship was observed between OH and cognitive status (normal cognitive function, MCI, AD, or VaD). OH was present in 22% in VaD subjects, 15% in AD subjects, 12% in MCI subjects and 4% in normal control subjects (p<0.01 for overall test).

Conclusion: Our results showed an association between OH and cognitive impairment and emphasize the need for longitudinal studies designed to evaluate the nature of the relationship between OH and cognitive decline.