ObjectivesIdentifying frequent users’ (≥3admissions/year) associated factors in an emergency department (ED), using a comprehensive geriatric assessment (CGA), describing the characteristics of patients over 65 years of age. MethodsA cross-sectional study was performed between August 2017 and June 2018 in an ED in Lisbon, Portugal. CGA was applied and completed with clinical records. Clinical, functional, mental and social scores were created based in Portuguese Society of Internal Medicine, and a statistical model was developed. ResultsCGA was applied to 426 patients over 64 years old in an ED. The mean age was 79.3, 84.7% had multimorbidity. 51.2%, 75.6%, and 40% had dependence on basic, instrumental, and walking activities, respectively. 52% had depressive symptoms, 65.7% had cognitive impairment, 63% were undernourished/at risk for malnutrition. 33.1% were socially at risk. Polypharmacy was present with a use on average of 6.5 drugs daily. Social, clinical, functional, and mental scores were unfavourable in 48.6%, 79.6%, 54.9% and 83.1% of the population, respectively. There were 2.7 hospital admissions/year and 39.9% were frequent ED users (≥3/year). The logistic regression model was weak, but showed that patients with polypharmacy, elevated Charlson Comorbidity index and an impairment nutritional status presented higher risk of being frequent users. ConclusionsThis study showed that 97.1% of patients had needs that would justify an interventional care plan. This intervention should be extended to primary care and nursing homes. While not providing a robust model, our study has indicated nutritional problems, polypharmacy, and an elevated Charlson index as the features with more weight in frequent users’ admissions.