Adults living in southern U.S. states that expanded their Medicaid programs under the Affordable Care Act experienced lower rates of physical and mental health decline, according to new research by investigators at Harvard Medical School and Vanderbilt University.
The study, published Jan. 6 in the journal Health Affairs, draws on self-reported data from 15,356 low-income individuals recruited predominantly at community health centers in 12 southern states as part of the Southern Community Cohort Study.
The results capture the effect of boosting access to health care for low-income populations, the research team said, and underscore the value of greater access to health services. At the time of the Affordable Care Act introduction, 14 states declined to take advantage of the program expansion.
The newly published analysis shows that after the program expansion, the number of Medicaid-insured adults increased by 7.6 percentage points, compared with the number of insured adults in nonexpansion states.
Barring a Medicaid expansion, the researchers estimated that 38.1 percent of adults would experience overall health decline in the absence of improved access to Medicaid.
After the expansion, the percentage of people reporting such decline was markedly lower than anticipated—36.3 percent—a drop of nearly 1.8 percentage points. Additionally, a greater number of people reported they had maintained their health status and did not experience worsening health, the analysis showed.
Even though the numbers may appear modest, the authors note, cumulatively they could yield a notable compound health benefit.
“The effect is sizable, analogous to the worst-ranked southern state rising about halfway up the rankings in state population health if it expanded Medicaid,” said study senior author J. Michael McWilliams, the Warren Alpert Foundation Professor of Health Care Policy in the Blavatnik Institute at HMS and a general medicine physician at Brigham and Women’s Hospital.
“Unlike many other studies, we were able to focus on some of the most vulnerable populations who stand to gain the most from insurance coverage,” he said.
Moreover, the findings shed new light on state-level debates over the merits of expansion, which have included questions over whether access to the safety net can serve as a substitute for health insurance coverage.
“Our study is the first to consider the pathways through which and populations for whom expanded access to Medicaid affects the health trajectory of low-income adults,” said lead author John Graves, associate professor of health policy at Vanderbilt University School of Medicine. “It fills an important gap between research that has found little evidence of health effects, and other research demonstrating that expanded Medicaid saved lives.”
Previous research has found modest changes in self-reported health and reductions in mortality associated with Medicaid expansion, but a review of 77 other studies published in 2018 in Health Affairs found that 60 percent of assessments of health status did not find evidence of beneficial impacts of the ACA’s expansion. This muddled evidence has contributed to state-level debates over whether accepting expansion funds could improve population health.
Of the 14 states that have not yet expanded Medicaid, nine are in the South and two border the region.
“Our research demonstrates that access to the safety net is an inadequate substitute for health coverage,” Graves said. “Health care policy experts and physicians have suspected this for a while but with our study, we now have the actual evidence showing that nonexpanding southern states could materially improve population health if they accept expansion funds.”
“This is what evidence is for—to tell us whether the benefits are worth the costs,” McWilliams said. “In this case, the evidence is increasingly clear that Medicaid expansions are worth it.”
Other investigators on the research included Laura Hatfield and Nancy Keating of HMS and William Blot of Vanderbilt University.
The work was supported by the National Cancer Institute under grant NIH 5R01 CA189152-05.
Adapted from a Vanderbilt University School of Medicine news release.