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 data set.
Methods: Data were extracted for 291,169 people aged 65 years or older registered with 314 general practices in the UK, 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 ratios (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 versus 2.4; P < 0.001) and were on more repeat medication (mean number of repeats 5.4 versus 4.2; P < 0.001). Those with dementia were more likely to have 5 or more physical conditions (age–sex standardised OR [sOR] 1.42, 95% confidence interval (CI) 1.35–1.50; P < 0.001) and were also more likely to be on 5 or more (sOR 1.46; 95% CI 1.40–1.52; P < 0.001) or 10 or more repeat prescriptions (sOR 2.01; 95% CI 1.90–2.12; P < 0.001). Conclusions: People with dementia have a higher burden of comorbid 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 multidisciplinary dementia specialists.