Does Decreased Access to Emergency Departments Affect Patient Outcomes? Analysis of Ami Population 1996-2005

We analyze whether decreased emergency department access (measured by increased driving time to the nearest ED) results in adverse patient outcomes or changes in the patient health profile for patients suffering from acute myocardial infarction. Data sources include 100% Medicare Provider Analysis and Review, AHA hospital annual surveys, Medicare hospital cost reports, and longitude and latitude information for 1995-2005. We define four ED access change categories and estimate a zip codes fixed-effects regression models on the following AMI outcomes: time-specific mortality rates, age, and probability of PTCA on the day of admission. We find a small increase in 30-day to 1-year mortality rates among patients in communities that experience <10-minute increase in driving time. Among patients in communities with >30-minute increases in driving time, we find a substantial increase in long-term mortality rates, a shift to younger ages (suggesting that the older ones die en route) and a higher probability of immediate PTCA. Most of the adverse effects disappear after the initial three-year transition window