The Effect of Medicaid Expansion on Diagnosis, Care, Treatment, and Health for Persons with Diabetes: Evidence from Medicaid Expansion in Wisconsin (WP-26-04)
Sadia Farzana, Andrew Owen, John Meurer, Ronald Ackermann, and Bernard Black
The authors report time-series evidence on the effects of expansion of Medicaid coverage under the 2014 Affordable Care Act (ACA), on healthcare and outcomes for persons with diabetes, including medium and longer-term effects. They focus on diabetes, as a common, often-underdiagnosed condition for which effective treatments exist, and on childless adults, who were a particular target for ACA expansion. The authors use difference-in-differences (DiD) analysis applied to a longitudinal, uniquely detailed (relative to prior work) dataset which includes visit-level electronic healthcare records over 2011-2022 from Medical College of Wisconsin (a major Milwaukee-centered health system) linked to Medicaid enrollment records. They compare a treatment group of 1,679 newly-enrolled childless adults with diabetes to a propensity-score-balanced control group of 1,600 already-insured adults with diabetes (mostly parents with children at home). Gaining insurance leads to sharply higher utilization (outpatient, ED, and hospitalization); and large increases in new diagnoses of diabetes and other chronic conditions; related prescriptions; and testing rates. The authors find improvement in intermediate health outcomes (blood sugar, blood pressure, and cholesterol levels), and suggestive evidence of improved longer-term outcomes (macrovascular events; advanced kidney disease; amputations). They also compare persons with diabetes to other persons; DiD coefficients are generally larger for persons with diabetes, but percentage changes are often higher for other persons.