Study: Medicaid expansion increases ER use

An increase in insured hospital patients due to Medicaid expansion led to a 40 percent rise in their visits to the emergency room, according to a study published in Science.

Furthermore, based on a Medicaid lottery program in Oregon, enrollment in Medicaid increased the likelihood of emergency department use by 7 percent, according to lead researcher Sarah Taubman of the National Bureau of Economic Research in Cambridge, Mass.

"These findings speak to one cost of expanding Medicaid, as well as its net effect on the efficiency of care delivered, and may thus be a useful input for informed decision-making balancing the costs and benefits of expanding Medicaid," Taubman and her team wrote.

The researchers separated emergency department visits based on time of day and whether or not they led to an admission. Approximately 90 percent were defined as outpatient emergency department visits and increased visits from Medicaid enrollees were "solely in outpatient visits." Expansion of Medicaid correlated with a rise in visits in all categories except those considered "emergent, nonpreventable." The greatest increase was among visits considered "primary care treatable" and "non-emergent," according to the study.

Several factors limited the generalizability of the study, according to the authors, including the predominantly white and city-based population used for the study, the fact that signup for the study was voluntary and the lack of follow-up study on patients' use of emergency services after 13 months.

"These limitations to generalizability notwithstanding, our study is able to make use of a randomized design that is rarely available in the evaluation of social insurance programs to estimate the causal effects of Medicaid on emergency department care," the authors wrote. "We find that expanding Medicaid coverage increases emergency department use across a broad range of visit types, including visits that may be most readily treatable in other outpatient settings."

A May 2013 study published in the New England Journal of Medicine found that while expansion of Medicaid in Oregon led to increased use of medical services, it did not cause measurable improvements in patient outcomes, FierceHealthcare previously reported.

To learn more:
- read the study (.pdf, subscription required)