Comorbidity and polypharmacy in people with dementia: insights from a large, population-based cross-sectional analysis of primary care data

Background: The care of older people with dementia is often complicated by physical comorbidity and polypharmacy, but the extent and patterns of these have not been well described. This paper reports analysis of these factors within a large, cross sectional primary care dataset.
Methods: Data was extracted for 291,169 people aged 65 years or over registered with 314 general practices in Scotland, of whom 10,258 had an electronically recorded dementia diagnosis. Differences in the number and type of 32 physical conditions, and the number of repeat prescriptions in those with and without dementia were examined. Age-gender standardised rates were used to calculate odds ratio (ORs) of physical comorbidity and polypharmacy.

Results: People with dementia, after controlling for age and sex had on average more physical conditions than controls (mean number of conditions 2.9 vs. 2.4; p<0.001) and were on more repeat medication (mean number of repeats 5.4 vs. 4.2; p<0.001). Those with dementia were more likely to have five or more physical conditions (age-sex standardised OR [sOR] 1.42, 95% CI 1.35 to 1.50; p<0.001) and were also more likely to be on five or more (sOR 1.46; 95% CI 1.40 to 1.52; p<0.001) or ten or more repeat prescriptions (sOR 2.01; 95% CI 1.90 to 2.12; p<0.001).

Conclusions: People with dementia have a higher burden of co-morbid physical disease and polypharmacy than those without dementia, even after accounting for age and sex differences. Such complex needs require an integrated response from general health professionals and multi-disciplinary dementia specialists.