Dr Ryan McHenry, an emergency medicine doctor in the west of Scotland and a researcher at Glasgow University, told the European Emergency Medicine Congress in Paris that the risk of a patient dying within 28 days of emergency department treatment rises by about one per cent for every ten per cent increase in the occupancy of the department that treated them. The estimate rests on 19,034 patients treated at 134 emergency departments across England, Wales and Northern Ireland during five separate periods in 2025 — a far larger sample than the single-site work that usually carries this argument, and a small slice of the roughly 7.3 million A&E attendances England recorded this summer alone.
What the study actually measured
Occupancy here is a ratio: patients being treated divided by treatment spaces such as cubicles. Fifty cubicles holding fifty patients is 100 per cent. Sixty patients in those fifty cubicles is 120 per cent. The researchers matched that figure, read on the day each patient was seen, against whether that patient died within 28 days of treatment, from any cause. Across the periods studied, the departments averaged 175 per cent occupancy — seven patients for every four spaces.
Corridor care — treatment in corridors and other spaces never designed for clinical use — was also associated with more deaths, at a magnitude the researchers describe as in line with the occupancy effect. They publish no separate effect size for it, and say occupancy is easier to measure and record, which is why it carries the headline. Extrapolating the one-per-cent gradient across the United Kingdom, the authors put the toll at 554 deaths a week — about 28,800 a year — against a hypothetical service with one space for every patient.
What the authors will not claim
This is an observational study, and McHenry does not say that crowding causes those deaths. He says the two are associated, that reducing crowding has the potential to save lives, and that the link is likely to hold in other countries with regional variation. No confidence interval for the one-per-cent gradient appears in the materials released with the presentation, and no hazard ratio is given in them. The work was presented at the congress rather than published as a peer-reviewed paper, and the authors say confirmation is a job for further studies.
The uncertainty around the headline number is theirs, not their critics'. The 554 figure is a point estimate, and they put the plausible span at 33 to 1,083 excess deaths a week — roughly 1,700 a year at the low end, 56,000 at the high end. The comparison case is stylised too: one space for every patient is a full-staffing counterfactual, not a reachable operating point for a service at 175 per cent.
Although we cover the majority of the emergency departments in the UK, this was still a relatively small study, and the possible range of expected deaths is therefore large; we estimate anywhere between 33 and 1,083 excess deaths are plausible.
Two smaller discrepancies are worth noting. Patient data came from 134 departments, while McHenry counts 139 departments as participating. And the sample covers England, Wales and Northern Ireland; Scotland, where the presenting author works, is not in it.
Where it sits against earlier UK estimates
Britain already has a running estimate of harm from emergency care, built another way. The Royal College of Emergency Medicine's State of Emergency Medicine in England analysis, published in June, applies a standardised mortality ratio drawn from earlier research — one additional death for every 72 patients who wait eight to 12 hours in a department before admission — and reaches 15,860 excess deaths in England in 2025, or 305 a week. That is a different exposure (long waits, not occupancy), geography (England alone) and method (a modelled ratio, not observed deaths against a same-day occupancy reading). McHenry's own gloss is cautious: the numbers, he says, track similar estimates of harm from long waits and crowding.
The operational context is not in dispute. The King's Fund recorded more than 2,000 patients a day receiving corridor care in England in May, and senior analyst Danielle Jefferies called the new study "another stark reminder of the harrowing situation patients and staff continue to face in emergency departments". GB News reported the weekly estimate as more than 550 patients "dying unnecessarily"; the authors frame it as excess deaths against a full-capacity counterfactual.
What would make it replicable
A peer-reviewed version with the full model would settle the questions the presentation leaves open: the hazard ratio and its interval, the length of the exposure window, how much of the association survives adjustment for case mix and for the hospital a patient arrives at. A stronger test would be replication against routine national occupancy and mortality data rather than five sampling periods, and a sample that includes Scotland and departments outside the UK.
The researchers have already put one tool in circulation: a free risk calculator at uncorkedcalculator.com, which lets staff enter conditions in their own department and read the risk that follows. The Royal College of Emergency Medicine's ask is that governments prioritise overcrowding, long waits and the associated risk to patients; McHenry says he and his colleagues are already engaging with governments to feed the work into policy.
The narrow story is a large, unusually direct measurement of a link that has mostly been argued from waiting-time data — carrying an uncertainty range wide enough that the authors, not their critics, say the estimate still needs confirming.