Importance: Emergency department (ED) visits are common and increasing. Whether outcomes associated with care in the ED are improving over time is largely unknown to date.
Objective: To examine trends in 30-day mortality rates associated with ED care among Medicare beneficiaries aged 65 years or older.
Design, setting, and participants: This cross-sectional study used a random 5% sample in 2009 and 2010 and a 20% sample from 2011 to 2016, for a total of 15 416 385 ED visits from 2009 to 2016 among Medicare beneficiaries aged 65 years or older.
Exposures: Time (year) as a continuous variable.
Main outcomes and measures: The primary outcome was 30-day mortality, overall and stratified by illness severity and hospital characteristics. Secondary outcomes included mortality rates on the day of the ED visit (day 0) as well as at 7 and 14 days. Changes in disposition from the ED (admission, observation, transfer, died in the ED, and discharged) over time were also examined.
Results: The sample included 15 416 385 ED visits (60.8% women and 39.2% men; mean [SD] age, 78.6 [8.5] years) at 4828 acute care hospitals. The percentage of patients discharged from the ED increased from 53.6% in 2009 to 56.7% in 2016. Unadjusted 30-day mortality declined from 5.1% in 2009 to 4.6% in 2016 (-0.068% per year; 95% CI, -0.074% to -0.063% per year; P < .001). After adjusting for hospital random effects, patient demographics, and chronic conditions, the adjusted 30-day mortality trend was -0.198% per year (95% CI, -0.204% to -0.193% per year; P < .001). The magnitude of this trend was greatest for patients with a high severity of illness (-0.662%; 95% CI, -0.681% to -0.644%; P < .001), followed by those with a medium severity of illness (-0.103% per year; 95% CI, -0.108% to -0.097% per year; P < .001) and those with a low severity of illness (-0.009% per year; 95% CI, -0.006% to -0.011% per year; P < .001). Declines in mortality were seen in each category of ED disposition, including visits resulting in admission (-0.356% per year; 95% CI, -0.368% to -0.343% per year; P < .001) as well as those resulting in discharge (-0.059% per year; 95% CI, -0.064% to -0.055% per year; P < .001). The decline was greater for major teaching hospitals (compared with nonteaching hospitals), nonprofit hospitals (compared with for-profit hospitals), and urban hospitals (compared with rural hospitals).
Conclusions and relevance: Among Medicare beneficiaries receiving ED care in the United States, mortality within 30 days of an ED visit appears to have declined in recent years, particularly for patients with the highest severity of illness, even as fewer patients are being admitted from an ED visit. This study's findings suggest that further study is needed to understand the reasons for this decline and why certain types of hospitals are seeing greater improvements in outcomes.