The Effect of Medicaid on Care and Outcomes for Chronic Conditions: Evidence from the Oregon Health Insurance Experiment

Health insurance may play an important role not only in immediate access to care but in the management of chronic disease, which would have implications for long-run care needs as well as health outcomes. Such causal connections are often difficult to establish, but we use Oregon’s 2008 Medicaid lottery to assess the management of diabetes and asthma, as well as several markers of physical health. This analysis complements several prior studies by introducing new data elements and by analyzing chronically ill subpopulations. While we had previously found that having insurance increases the diagnosis and use of medication for diabetes, we show here that it does not significantly increase the likelihood of diabetic patients receiving recommended care such as eye exams and regular blood sugar monitoring, nor does it improve the management of patients with asthma. We also find no effect on measures of physical health including pulse, obesity, or blood markers of chronic inflammation. Effects of Medicaid on health care utilization appear similar for those with and without pre-lottery diagnoses of chronic physical health conditions. Thus, while Medicaid is an important determinant of access to care overall, it does not appear that Medicaid alone has detectable effects on the management of several chronic physical health conditions, at least over the first two years in this setting. However, sample limitations highlight the value of additional research.