Epidemiology and outcomes of geriatric and non-geriatric patients with drug allergy labels in Hong Kong.

INTRODUCTION: Adverse drug reactions are more common in geriatric patients than in younger patients, but there have been insufficient studies concerning the epidemiology or burden of drug allergy labels in geriatric patients. We prospectively investigated the prevalence and outcomes of geriatric patients with drug allergy labels in a cohort of hospitalised patients.
METHODS: Patients admitted to a regional hospital over a 6-month period were recruited for this study. All patients with drug allergy labels were prospectively followed until discharge; clinical data were anonymously extracted for analyses. Patients were categorised into either geriatric (aged ≥65 years) or non-geriatric (aged <65 years) groups. Demographic characteristics, clinical outcomes, and prevalences of drug allergy labels were compared between groups.
RESULTS: There were 4361 admissions involving 3641 patients during the 6-month study period. Overall, 492 patients (13.5%) had drug allergy labels, consisting of 151 non-geriatric patients (30.7%) and 341 geriatric patients (69.3%). The prevalence of drug allergy labels did not significantly differ between geriatric and non-geriatric patients (13.5% vs 13.5%, P=0.976). Significantly more patients in the geriatric group had drug allergy labels to cardiovascular system drugs (15.5% vs 4.6%, P=0.001). Geriatric patients had a significantly lower rate of direct discharge from the hospital (73.0% vs 88.1%, P<0.001) and required transfers to convalescent or rehabilitation care for further management.
CONCLUSIONS: More than 13% of hospitalised geriatric patients had drug allergy labels. The leading causes of drug allergy labels were similar between geriatric and non-geriatric patients. Geriatric patients with drug allergy labels had significantly more labelled allergies to cardiovascular system drugs and adverse clinical outcomes.