Relationship between orthostatic hypotension and cognitive impairment in the elderly

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

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).

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).

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.