Epidemiology of dementia onset captured in Canadian primary care electronic medical records.

Abstract

Dementia is an increasing concern in many countries, especially in those experiencing rapid growth in the proportion of older adults in their population. This study aims to describe trends and demographic characteristics of incident dementia cases in community-dwelling older adults managed by primary care physicians. We used electronic medical records from the Canadian Primary Care Sentinel Surveillance Network database to conduct a retrospective analysis to determine the number of, and trends for, incident diagnoses of dementia. Age-standardized annual incidence rates were calculated. Participants in our cohort are Canadian community dwelling seniors aged 65+ years who were not diagnosed with dementia before baseline with at least six years of record at their primary care clinics. The cohort consisted of 39 067 patients of whom 57% were females; the mean (SD) follow-up was 8.4 (1.5) years. During follow-up, 4935 patients were diagnosed with dementia. The risk for dementia diagnosis increased with increasing age but decreased in the last four years among people aged 80 and older at baseline (P < 0.001). People with dementia were more likely to be females (P = 0.001) and urban residents (P < 0.001), they are less likely to be classified into the least deprived group (P = 0.012). The incidence of dementia diagnosis increased with age except in the oldest old in both sexes. This may be attributed to the effect of mortality competing risk. Future research on the association between risk factors and dementia should consider studying dementia among the oldest old separately to minimize bias.