Patterns of health service use in community living older adults with dementia and comorbid conditions: a population-based retrospective cohort study in Ontario, Canada

Background: Patients with dementia have increased healthcare utilization and often have comorbid chronic conditions. It is not clear if the increase in utilization is driven by dementia, the comorbidities or both. The objective of this study was to describe the number and types of comorbid conditions in a population-based cohort of older adults with dementia and how the level of comorbidity impacts dementia-related and non-dementia-related health service utilization. Methods: This study is a retrospective cohort study using multiple linked administrative databases to examine health service utilization and costs of 100,630 community-living older adults living with pre-existing dementia in Ontario, Canada. Comorbid conditions and health service utilization were measured using administrative data (physician visits, emergency department visits, hospitalizations, and homecare contacts). Results: Nearly all, 96.3 %, had at least one comorbid condition, while 18.4 % had five or more comorbid conditions. The most common comorbid conditions were hypertension (77.8 %), and arthritis (66.2 %). All types of utilization increased consistently with the number of comorbid conditions. The average number of dementia-related services tended to be similar across all levels of comorbidity while the average number of non-dementia related visits tended to increase with the level of comorbidity. Conclusions: Comorbidities in community-living older adults with dementia are common and account for a substantial proportion of health service use and costs in this population. Our results suggest that comprehensive programs that take a holistic view to identify the needs of patients in the context of other comorbidities are required for persons with dementia living in the community.