• emergency ambulance systems
• effectiveness
• crowding

Like many emergency physicians of a certain age, we find ourselves nostalgic for a time when it felt easier to admit patients into the hospital than now. Many of us now find ourselves feeling that we discharge many patients from the ED who we would have admitted years ago. It turns out that this hunch is correct. In an enormous retrospective database study, Steven Wyatt et al 1 examined admission thresholds across 47 EDs in England over a 5-year period. They used a simple regression model to adjust for known predictors of admission, including robustly recorded items such as age and sex, and less well recorded items such as diagnosis.

Initially, the conversion rate (the number of admissions divided by the number of attendances) looks similar across the years, but when adjusted for various measures of acuity, there is a 3% reduction in admissions over the 5-year period. This reduction occurs across all patient groups, but is greatest for adult walk-in attendances and least for children arriving by ambulance.

While the effect sizes are small, the very large study size allows the authors to estimate that 137 000 hospital admissions were avoided …