OBJECTIVE: To determine the prevalence of orthostatic hypotension (OH), low blood pressure and dizziness, falls and fractures in patients with organic dementia.

DESIGN: We prospectively studied 151 patients, assessing the prevalence of OH, hypertension, heart disorders, diabetes mellitus and the use of medication possibly associated with OH.

SETTING: The patients were admitted to our psychogeriatric clinic as part of routine clinical investigation of their dementia.

PATIENTS: Forty-six patients with Alzheimer's disease (AD), 28 patients with frontotemporal dementia (FTD) and 77 patients with vascular dementia (VaD) were investigated.

MAIN OUTCOME MEASURE: Due to the paucity of information about the prevalence of OH in organic dementia, this study is mainly explorative in nature, thus preventing explicit hypothesis formulation. However, clinical impressions indicated a higher prevalence of OH in organic dementia than normally seen in healthy elderly.

RESULTS: OH/low blood pressure was present in 39-52% of the patients. The majority reached their maximum systolic decrease within 5 minutes of standing, but in 20-30% the maximum blood pressure drop occurred after 5 minutes or later. In 38%, the systolic blood pressure drop was more than 40 mm Hg. Hypertension and heart disease was found only in AD and VaD, with no difference between those with and without OH/low blood pressure. Falls and fractures were common in orthostatic and hypotensive patients, with an incidence of more than 50% in AD and VaD.

CONCLUSIONS: The results support our clinical impressions that OH and low blood pressure is common and an important factor in organic dementia.