The impact of insurance and a usual source of care on emergency department use in the United States.

Background. Finding a usual source of care (USC) is difficult for certain populations. This analysis determines how insurance type and having a USC affect the settings in which patients seek care. Methods. In this cross-sectional study of the 2000-2011 Medical Expenditure Panel Surveys, we assessed the percentage of low-income persons with half or more of their ambulatory visits to the emergency department (ED). Respondents were stratified based on insurance type and presence of a USC. Results. In 2011, among Medicaid enrollees without USCs, 21.6% had half or more of their ambulatory visits to EDs compared to 8.1% for those with USCs. Among the uninsured without USCs, 24.1% went to an ED for half or more of their ambulatory visits compared to 8.8% for those with USCs in 2011. Among the privately insured without USCs, 7.8% went to an ED for half or more of their ambulatory visits compared to 5.0% for those with USCs in 2011. These differences remained in multivariate analyses. Conclusions. Those who lack USCs, particularly the uninsured and Medicaid enrollees, are more likely to rely on EDs.