Emergency department involvement in the diagnosis of cancer among older adults: a SEER-Medicare study.

BACKGROUND: Internationally, 20-50% of cancer is diagnosed through emergency presentation, which is associated with lower survival, poor patient experience, and socioeconomic disparities, but population-based evidence about emergency diagnosis in the U.S. is limited. We estimated Emergency Department (ED) involvement in the diagnosis of cancer in a nationally representative population of older US adults, and associations with sociodemographic, clinical, and tumor characteristics. METHODS: We analyzed SEER-Medicare data for Medicare beneficiaries (≥66 years old) diagnosed with female breast, colorectal, lung and prostate cancers (2008-2017), defining their earliest cancer-related claim as their index date, and patients who visited the ED 0-30 days before their index date to have "ED involvement" in their diagnosis, with stratification as 0-7 or 8-30 days. We estimated covariate-adjusted associations of patient age, sex, race/ethnicity, marital status, comorbidity score, tumor stage, diagnosis year, rurality, and census tract poverty with ED involvement using modified Poisson regression. RESULTS: Among 614,748 patients, 23% had ED involvement with 18% visiting the ED in the 0-7 days before their index date. This varied greatly by tumor site: breast 8%, colorectal 39%, lung 40%, prostate 7%. In adjusted models, older age, female sex, non-Hispanic Black and Native Hawaiian/Other Pacific Islander race, being unmarried, recent diagnosis year, later-stage disease, comorbidities, and poverty were associated with ED involvement. CONCLUSIONS: The ED may be involved in the initial identification of cancer for 1 in 5 patients. Earlier, system-level identification of cancer in non-ED settings should be prioritized, especially among underserved populations.