40% of UK Emergency Admissions Could Be Managed as Same-Day Outpatient Care

For health systems straining under the weight of aging populations, the question of which hospital admissions are truly unavoidable carries enormous practical weight. When nearly half of all emergency admissions may be clinically suitable for same-day management without an overnight bed, the efficiency gap between current practice and best practice becomes a system-level intervention target — not merely an operational footnote.

This large retrospective analysis examined over 1.5 million emergency department attendances and 660,000 admissions across 21 NHS acute hospitals in England during a 12-month window spanning late 2021 to 2022. Using established ambulatory emergency care (AEC) definitions — conditions where evidence supports same-day acute management without inpatient admission — the study found that AEC conditions accounted for 29.6% of all ED attendances and a striking 40.8% of emergency admissions. Critically, the rate at which AEC-eligible patients were actually admitted varied substantially between hospitals, as did the proportion of AEC admissions lasting fewer than two days, suggesting wide practice variation rather than uniform clinical necessity. Patients aged 65 and older and those from lower socioeconomic backgrounds showed distinct admission patterns, pointing to compounding social and clinical complexity.

This research sits within a well-established literature on preventable hospitalizations, but its scale — over 1.5 million attendances federated across 21 sites with consistent AEC coding — gives it unusual epidemiological weight for an NHS context. The finding that inter-hospital variability is substantial is arguably the most actionable insight: it implies that high-admission hospitals are not simply managing sicker populations, but may be under-deploying ambulatory pathways. For adults managing chronic conditions, this matters because AEC-model care — when well-resourced — is associated with comparable safety outcomes and higher patient satisfaction than inpatient admission. The study is observational and retrospective, limiting causal inference, and the 2021–2022 window captures a post-COVID period with atypical care-seeking patterns. Still, the magnitude of potentially avoidable admissions suggests this is confirmatory of a systemic gap, not an outlier finding.