Non-patient factors related to admission vs. referral for cancer patients receiving an initial diagnosis in the emergency department.

167 Background: Emergency presentation (EP) of cancer, where the diagnosis is made through emergency care, is a commonly studied phenomenon internationally, and is linked to older age, advanced disease, disadvantage, and poor prognosis. We recently identified two subgroups of EP patients which may be specific to US settings: those admitted from ED for diagnosis (inpatient EPs; more common among patients with aggressive cancer, late stage disease) and those referred for outpatient workup (outpatient EPs; more common in patients residing in rural areas). However, little is known about how non-patient factors, such as hospital or system factors, affect whether a patient is admitted upon EP. Here we provide a descriptive analysis examining patterns of inpatient EP vs. outpatient EP by hospital type, location, day of the week and season of ED attendance in a population of Medicare beneficiaries diagnosed with 6 cancer types. Methods: We studied SEER-Medicare beneficiaries 66+ years old with emergency diagnosis of breast, colorectal, lung, ovarian, prostate, or uterine cancer. We examined patterns of inpatient vs. outpatient EP by hospital characteristics including Commission on Cancer (CoC) Accredited hospital, rural hospital status, teaching affiliation, hospice beds, and hospital size. We also classified the ED attendance on weekday/weekend and by season. Results: The study population included 161,697 EP patients; 123,857 (77%) inpatient EP and 37,840 (23%) outpatient EP. Inpatient EPs were more common at larger (≥500 beds: 84% vs. < 100 beds: 49%), teaching (83% vs. 69% non-teaching) and CoC hospitals (80% vs. 73% non-CoC). Outpatient EPs were more common at smaller ( < 100 beds: 51% vs. ≥500 beds: 15%) and rural hospitals, where < 0.1% were admitted. Outpatient EPs were also slightly more common on weekends (25% vs. 23% on weekdays). Greater weekend outpatient EPs were more pronounced for breast and uterine cancer. EP care pathways did not vary with hospice capacity or season. Conclusions: Non-patient factors appear to influence the likelihood of admission following an EP for cancer diagnosis. Our results underscore the importance of hospital size/capacity in managing cancer emergencies, with smaller/rural EDs more likely to refer patients for outpatient follow-up, potentially due to limited oncological care capacity or less acute presentations in rural settings, compounded by primary care shortages. Increased outpatient referrals on weekends suggests that patients with less urgent cases may delay seeking care, or that referral patterns may be influenced by the availability of specialized care and the increased demand for acute care during weekends. However, resulting delays in care, particularly when patients are primarily receiving care in acute care settings, could negatively impact timely diagnosis and treatment, affecting patient outcomes and care quality.