A clinicopathological comparison of community-based and clinic-based cohorts of patients with dementia.

Objectives: To compare the sensitivity and specificity of the clinical diagnosis of Alzheimer disease, the distribution of pathological causes, and the demographic and clinical characteristics of 2 different groups of patients with dementia.

Design: Retrospective clinicopathological study.

Setting: A memory disorder clinic in a university hospital and a multiethnic community.

Patients: Sixty-three patients from a memory disorder clinic and 26 patients from a large community-based study who underwent autopsy after clinical evaluation.

Main Outcome Measures: Differential distribution of clinical and pathological findings, with clinicopathological correlations.

Results: Clinic patients were younger at diagnosis, more educated, and more likely to be white. Of the 63 clinic patients we evaluated, 29 (46%) had a pathological diagnosis of definite AD, 15 (24%) had a diagnosis of mixed AD, and 19 (30%) had a diagnosis of another type of dementia. The pathological diagnoses in the community patients were distributed as follows: 6 (23%) had definite AD, 6 (23%) had mixed AD, 6 (23%) had cerebrovascular disease, and 8 (31%) had another type of dementia. The difference in distribution of pathological diagnoses between these 2 groups was only significant for cerebrovascular diseases. For patients seen at the clinic, the sensitivity of the clinical diagnosis of AD was 98% and the specificity was 84%; for the community group, the sensitivity was 92% and the specificity was 79%.

Conclusions: The difference in sensitivity and specificity of clinical diagnosis was not statistically significant between the groups of clinic patients and community patients. Dementia associated with cerebrovascular disease was more prevalent in the community sample. This difference may be attributable to clinical and demographic differences between the 2 groups.