Emergency department utilization after the implementation of Massachusetts health reform.

Study Objective: Health care reform in Massachusetts improved access to health insurance, but the extent to which reform affected utilization of the emergency department (ED) for conditions potentially amenable to primary care is unclear. Our objective is to determine the relationship between health reform and ED use for low-severity conditions.

Methods: We studied ED visits, using a convenience sample of 11 Massachusetts hospitals for identical 9-month periods before and after health care reform legislation was implemented in 2006. Individuals most affected by the health reform law (the uninsured and low-income populations covered by the publicly subsidized insurance products) were compared with individuals unlikely to be affected by the legislation (those with Medicare or private insurance). Our main outcome measure was the rate of overall and low-severity ED visits for the study population and the comparison population during the period before and after health reform implementation.

Results: Total visits increased from 424,878 in 2006 to 442,102 in 2008. Low-severity visits among publicly subsidized or uninsured patients decreased from 43.8% to 41.2% of total visits for that group (difference=2.6%; 95% confidence interval [CI] 2.25% to 2.85%), whereas low-severity visits for privately insured and Medicare patients decreased from 35.7% to 34.9% of total visits for that group (difference=0.8%; 95% CI 0.62% to 0.98%), for a difference in differences of 1.8% (95% CI 1.7% to 1.9%).

Conclusion: Although overall ED volume continues to increase, Massachusetts health reform was associated with a small but statistically significant decrease in the rate of low-severity visits for those populations most affected by health reform compared with a comparison population of individuals less likely to be affected by the reform. Our findings suggest that access to health insurance is only one of a multitude of factors affecting utilization of the ED.