The association of comorbidity and health service utilisation among patients with dementia in the UK: a population-based study
The majority of people with dementia have other long-term diseases, the presence of which may affect the progression and management of dementia. This study aimed to identify subgroups with higher health care needs, by analysing how the use of health care services by people with dementia varies with having additional long-term diseases (comorbidity).
A retrospective cohort study based on health data from the Clinical Practice Research Datalink (CPRD) was conducted. Incident cases of dementia diagnosed in the year commencing 1 March 2008 were selected and followed for up to five years. The number of comorbidities was obtained from a set of thirty-four chronic health conditions. Service utilisation (primary care consultations, hospitalisations and prescriptions) and time-to-death were determined during follow-up. Multi-level negative binomial regression and Cox regression, adjusted for age and gender, were used to model differences in service utilisation and death between differing numbers of comorbidities.
Data from 4,999 people (14,866 person-years of follow-up) were analysed. Overall, 91.7% of people had one or more additional comorbidities. Compared with those with 2 or 3 comorbidities, people with ≥6 comorbidities had higher rates of primary care consultations (rate ratio 1.31, 95% confidence interval 1.25-1.36), prescriptions (RR 1.68, 95% CI 1.57-1.81), and hospitalisation (RR 1.62, 95% CI 1.44-1.83), and higher risk of death (hazard ratio 1.56, 95% CI 1.37-1.78).
In the UK, people with dementia with higher numbers of comorbidities die earlier and have considerably higher health service utilisation in terms of primary care consultations, hospital admissions and prescribing. This study provides strong evidence that comorbidity is a key factor that should be considered when allocating resources and planning care for people with dementia.