The association between an early diagnosis of dementia and secondary health service use: A retrospective cohort study using electronic health records: Epidemiology / Prevalence, incidence, and outcomes of MCI and dementia

Background: Dementia policy suggests diagnosing dementia early can reduce the risk of potentially harmful hospital admissions or emergency department (ED) attendances, however, there is little evidence to support this. A diagnosis of Mild Cognitive Impairment (MCI) before dementia is a helpful proxy to explore early diagnosis. This study investigated the association between an early diagnosis of dementia and subsequent hospitalisations and ED attendances.

Method: A retrospective cohort study of electronic health care records from 15,836 patients from a large secondary care database in South London, UK. Participants were divided into two groups: those with a diagnosis of MCI before dementia, an early diagnosis, and those without. Cox regression models were used to compare the risk of hospitalisation and ED attendance after dementia diagnosis and negative binomial regression models were used to compare the average length of stay and average number of ED attendances.

Results: Participants with an early diagnosis were more likely to attend ED after their diagnosis of dementia (HR= 1.09, CI= 1.00 – 1.18), however there was no difference in the number of ED attendances (IRR= 1.04, CI= 0.95 – 1.13). There was no difference in the risk of hospitalisation (HR= 0.99, CI= 0.91 – 1.08) or length of stay between the groups (IRR= 0.97, CI= 0.85 – 1.12).

Conclusion: The findings of this study do not support the assumption that an early diagnosis reduces the risk of hospitalisation or ED attendance. The patterns of health service use in this paper could reflect help-seeking behaviour before diagnosis or levels of co-morbidity.