Winter all year round in urgent and emergency care: a large retrospective analysis of routinely collected NHS data across England, 2021–2022

‘Winter pressures’ in urgent and emergency care (UEC) are widely accepted but have had little empirical attention. Amidst annually increasing demand for UEC and reports of extreme strain during winter, we aimed to understand the extent and nature of seasonal demand by analysing routine data from Emergency Departments (ED) and acute Admitted Patient Care (APC) episodes across England. This was a retrospective observational analysis using data from 26 hospitals and 22 EDs between 2021-11-1 and 2022-10-31 comparing emergency attendances and acute admissions between winter (October-March) and summer (April-September). Main outcomes included ED waiting times, length of admissions, the number of investigations, treatments and procedures received, and whether the contact was considered avoidable. Using a novel ‘federated’ approach exploiting local relationships with data providers, regional researchers analysed local data and provided summary statistics and analysis results to the lead site. Aggregation of summary results established a picture of seasonal demand across the country, and an understanding of regional variation in seasonal trends. 1,549,205 ED attendances (775,810 winter; 50.1%) and 747,685 APC admissions (368,910 winter, 49.3%) were analysed. We found no systematic seasonal differences in the number or nature of presentations. While regional variation existed for many outcomes, no nationally consistent effect of winter was found for any measure. Winter pressures in UEC may not be driven by large differences in the number, avoidability or acuity of ED attendances or APC admissions. Rather, UEC may be operating at or near to capacity all year, meaning small fluctuations in demand or in the complexity of presentations may cause significant strain on an over-burdened system. Focus on managing seasonal demand should be modified to address year-round pressure. Effective policy may require structural reconfiguration to better regulate demand.