Prevalence of Associated Diseases in Different Types of Dementia Among Elderly Institutionalized Patients: Analysis of 3447 Records

Objective: To determine the prevalence of dementia in a population of hospitalized or institutionalized elderly patients, and that of associated diseases according to dementia type.

Design: Retrospective analysis of a database of diagnostic codes.

Subjects: All patients admitted to 1 of the 4 geriatric units participating in the study at the Charles Foix Hospital between 1980 and 1989.

Measurements: All diagnoses mentioned in the discharge summary that could cause or contribute to hospitalization were recorded for each patient. A final list of 54 different diagnoses could be recorded for each patient. Dementia was subdivided into 3 subtypes: Alzheimer dementia (DAT), vascular dementia (VD), and other types of dementia (unclassifiable dementia).

Main Results: The study involved 3447 patients aged 81.0 +/- 8.3 years, of whom 27.7% were men. Dementia was the most frequent disease in this population (34.3%); Alzheimer disease was responsible for 15%, vascular dementia for 9.5%, and other types for 9.8%. The average number of associated diseases was 3.23 +/- 2.10 in the Alzheimer dementia group, 4.73 +/- 2.38 in the vascular dementia group, and 3.96 +/- 2.26 in the nondemented group. Parkinson disease was present in 15.5% of patients with unclassifiable dementia, compared with 7.6% in the nondemented group (P < 0.001). There were significantly more diseases commonly seen in bedridden patients in the group of patients with both other types of dementia and Parkinson disease than in the group of other types of dementia patients without Parkinson disease (P < 0.01).

Conclusion: Dementia was the most common disease observed in our elderly institutionalized population. Alzheimer patients had significantly fewer associated diseases than nondemented patients, whereas the reverse was found in the vascular dementia group. The co-existence of Parkinson disease and dementia in our population was associated with the poorest health status, as these patients were more likely to present simultaneously such conditions as pressure sores, incontinence, dehydration, or iatrogenesis.