The current crisis in the emergency care system is characterized by worsening emergency department (ED) overcrowding.  Lack of health insurance is widely perceived to be a major contributing factor to ED overcrowding in the United States.  This study aimed to compare ED visit rates in the United States and Ontario, Canada, according to demographic and clinical characteristics.

This was a cross sectional study consisting of a nationally representative sample of 40,253 ED visits included in the 2003 National Hospital Ambulatory Medical Care Survey in the United States, and all ED visits recorded during 2003 by the National Ambulatory Care Reporting System in Ontario, Canada.  The main outcome was the number of ED visits per 100 population per year.

The annual ED visit rate in the United States was 39.9 visits (95% confidence interval = 37.2 to 42.6) per 100 population, virtually identical to the rate in Ontario, Canada (39.7 visits per 100 population).  In both the United States and Ontario, Canada, those aged 75 years and older had the highest ED visit rate and women had a slightly higher ED visit rate than men.  The most common discharge diagnosis was injury/poisoning, accounting for 25.6% of all ED visits in the United States and 24.7% in Ontario, Canada.  Overall, 13.9% of ED patients in the United States were admitted to hospitals, compared with 10.5% in Ontario, Canada.

ED visit rates and patterns are similar in the United States and Ontario, Canada. Differences in health insurance coverage may not have a substantial impact on the overall utilization of emergency care.