Trends in Mortality for Medicare Beneficiaries Treated in the Emergency Department From 2009 to 2016

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