Not only did the researchers compare death rates before and after expansion, they also compared rates between states that expanded Medicaid and states that did not. This method gave the researchers two layers of comparison—before 2014 versus after and expansion states versus non-expansion states—for determining whether the differences were associated with Medicaid expansion, Trivedi said.
The adjusted absolute reduction in mortality in expansion states versus non-expansion states was 0.6 percentage points. Since end-stage renal disease affects more than 100,000 Americans each year, 0.6 percentage points equals hundreds of deaths annually, Trivedi said.
Trivedi says that more research is needed to determine exactly what caused the decrease in deaths, but the study suggests expanded insurance coverage, which provided better access to care, was the key factor in reducing mortality among this group. Medicaid expansion reduced the rate of end-stage renal disease patients without insurance by 4.2 percentage points, primarily through Medicaid coverage.
“Multiple factors not explored in our paper may have contributed to the reduction of mortality among patients with end-stage renal disease,” said Shailender Swaminathan, lead author and an adjunct assistant professor of health services, policy, and practice. “Medicaid may have resulted in better adherence to treatment sessions, normally three times a week, because it eliminated co-payments of about $150 per week. On the other hand, because out-of pocket medical payments were reduced, Medicaid may have also improved patients’ finances, thereby improving health. More research may be essential to unravel this.”
Medicaid expansion also improved pre-dialysis care for kidney disease, as indicated by the surgical placement of a fistula or graft before beginning dialysis, Trivedi said. Fistulas and grafts—two methods for accessing the bloodstream for dialysis—are less likely to become infected than temporary venous catheters, and in expansion states there was an increase of 2.3 percentage points in the number of patients beginning dialysis with a fistula or graft.