Identifying delirium in older adults presenting to a primary care out-of-hours (OOH) service: a retrospective cohort study

INTRODUCTION: Out-of-hours (OOH) services provide urgent primary care outside normal General Practice (GP) hours, serving patients who cannot wait for routine service. Delirium is commonly associated with acute illness, causes distress and leads to poor outcomes. However, little is known about delirium presentations in OOH services. We aimed to investigate using records from an OOH service in South-West England. METHODS: The database contained 33 345 contacts with patients ≥65 years attending the OOH service. We screened consultations during April and July 2019, and January 2020 using an automated search then clinical review by two independent GPs. We validated our search strategy by reviewing a random sample of 100 'search-negative' consultations initially and assessed inter-rater reliability. Patient characteristics were compared using Chi-squared tests. RESULTS: Of 4288 consultations with patients ≥65 years in the study periods, 402 (9.4%) involved possible or probable delirium. A further 74 (1.7%) had end-of-life delirium and were excluded from further analysis. Patients with delirium were older (mean age 84.4 years vs. 80.1 years), and more often had dementia (46.6% vs. 10.4%, P < .001). 67.9% of delirious patients required home visits, compared to 22.2% without delirium (P < .001). Patients with delirium were admitted to hospital twice as often as those without (20.6% vs. 8.5%, P < .001). CONCLUSIONS: Delirium is a common OOH presentation, representing ~10% of consultations with patients ≥65 years. These patients often have cognitive impairment, require home visits and are more likely to be admitted to hospital. These findings are important for planning urgent care services tailored to the needs of older people.