Medicaid Expansions Improve Insurance and Outcomes for Poor, Study Shows

Marcia Frellick

April 19, 2016

States that expanded Medicaid under the Affordable Care Act (ACA) have seen improvements for low-income people in insurance coverage and quality, use of healthcare, and higher rates of diagnosis for chronic diseases, new data show.

The study, published online April 19 in the Annals of Internal Medicine, compared changes in outcomes among nonelderly adults with incomes below 138% of the federal poverty level in the 26 states that implemented Medicaid expansions in 2014 with outcomes for adults in states that did not.

Laura R. Wherry, PhD, from the Division of General Internal Medicine & Health Services Research at the David Geffen School of Medicine at University of California, Los Angeles, and Sarah Miller, PhD, from the University of Michigan, Stephen M. Ross School of Business in Ann Arbor, found that insurance coverage increased by 7.4 percentage points (95% confidence interval [CI], 3.4 - 11.3 percentage points) and Medicaid coverage increased by 10.5 percentage points (95% CI, 6.5 - 14.5 percentage points) compared with in nonexpansion states.

They write that this study also gives the first evidence of increased use of healthcare in expansion states. They saw significant increases in adults reporting an overnight hospital stay (2.4 percentage points; 95% CI, 0.7 - 4.2 percentage points) or visit to a physician (6.6 percentage points; 95% CI, 1.3 - 12.0 percentage points) in the previous year compared with those in states that did not expand Medicaid.

The authors explain the larger implications of the finding: "Under the assumption that the observed 6.6–percentage point increase in reported physician visits and the 2.4–percentage point increase in hospital stays associated with the expansions are entirely attributable to the 10.5% of the population who gained Medicaid coverage, our estimates imply that Medicaid enrollment increased the likelihood of a physician visit by 62.9 percentage points and the likelihood of a hospital stay by 22.9 percentage points for each newly enrolled beneficiary over a 12-month period."

Diagnosis rates also improved for diabetes and high cholesterol, but not hypertension. Diabetes diagnoses were up by 5.2 percentage points (95% CI, 2.4 - 8.1 percentage points), and high cholesterol diagnoses rates were up 5.7 percentage points (95% CI, 2.0 - 9.4 percentage points) in the expansion states.

However, the researchers found no improvement in self-reported health status among Medicaid enrollees. The authors say a possible explanation for this is that increased contact with healthcare providers may have given them more knowledge about their health, which could have negatively affected perceived health in the short term.

The study used data for 2010 to 2014 from the National Health Interview Survey, a nationally representative annual survey conducted by the National Center for Health Statistics.

In an accompanying editorial, Jeffrey T. Kullgren, MD, MPH, from the VA Ann Arbor Healthcare System and the University of Michigan in Ann Arbor, writes that the large national look at the evidence may slice through the political contention surrounding the ACA and Medicaid expansion.

One of the most important findings for clinicians, he writes, is the increase in diagnoses for chronic diseases, "which could prompt early treatment and provide important downstream health benefits."

The study of 40,427 adults should inform future debates, he writes. But whether it will encourage states to expand Medicaid remains to be seen.

"How states decide will ultimately affect the health and well-being of many low-income Americans," he notes.

He also points out that the study was not able to assess a key threat to maintenance of higher-quality coverage, the churning of eligibility, which leads to enrollees moving into and off Medicaid and can negate its benefits. This should be addressed by policymakers to stabilize coverage, he writes.

He also points out that increased use of healthcare in 2014 may be a result of initial pent-up demand.

"It will be critically important to monitor these trends over time so that states can prepare for predicted patterns of utilization who gain Medicaid coverage," he writes.

The authors have disclosed no relevant financial relationships. Dr Kullgren reports receiving personal fees from SeeChange Health and personal fees from HealthMine outside the submitted work.

Ann Intern Med. Published online April 19, 2016. Article abstract, Editorial extract


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