Diabetes and dementia in long-term care

OBJECTIVES: To examine the presence or absence of dementia, and the prevalence rates for different dementias, in patients with and without adult onset diabetes (AODM). DESIGN: Chart survey. SETTlNG: A public long-term care facility in Rochester, New York, chosen to provide an enriched sample with respect to the diseases and demographic variables of interest. PARTICIPANTS: All long-term care residents in the facility aged 50 years or older (n = 476), mean age 74.8 years. Thirty-six (7.6%) had probable Alzheimer's disease (AD), 49 (10.3%) had possible AD, 38 (8.0%) had clinically diagnosed vascular dementia, 84 (17.6%) had unspecified dementias, and 269 (56.5%) were not demented. MEASUREMENTS: Demographic data, dementia and diabetes determined on the basis of extraction of chart data, and hypertension, myocardial infarction, congestive heart failure, and hypercholesterolemia determined on the basis of chart diagnoses. RESULTS: There were 99 residents with AODM in the sample, a prevalence rate of about 21%. The rates of both dementia and AODM were as expected for this age group and setting. Patients with probable or possible AD had the lowest rates of AODM (0 and 6.1%, respectively), and patients with vascular dementia had the highest rates of AODM (47.4%). Age, sex, and race influenced both the risk of having a dementia and the type of dementia. When these variables were adjusted for in multiple logistic regression, however, AODM remained a robust predictive factor because of its significant negative association with AD. Patients with unspecified dementias and no dementia showed rates of AODM (about 20%) that were roughly comparable and intermediate between vascular dementia and AD. CONCLUSIONS: In our study, AD diagnosed clinically and AODM did not co-occur, whereas AODM was associated with vascular dementia diagnosed clinically. Conversely, in non-Alzheimer, nonvascular dementias diagnosed clinically, the rates of AODM were equivalent to those in nondemented patients. These findings are in agreement with some, but not all, previous studies.