Senate Passes Insurance Industry Aid Bill (Photo credit: Mike Licht, NotionsCapital.com)

Into the maelstrom of debate over whether Medicaid should cover more people comes a new study by Harvard researchers who found that when states expanded their Medicaid programs and gave more poor people health insurance, fewer people died.

The study, published online Wednesday in The New England Journal of Medicine, comes as states are deciding whether to expand Medicaid by 2014 under the Affordable Care Act, the Obama administration’s health care law. The Supreme Court ruling on the law last month effectively gave states the option of accepting or rejecting an expansion of Medicaid that had been expected to add 17 million people to the program’s rolls.

Seems fairly reasonable. So why would anyone reject the expansion?

Medicaid expansions are controversial, not just because they cost states money, but also because some critics, primarily conservatives, contend the program does not improve the health of recipients and may even be associated with worse health. Attempts to research that issue have encountered the vexing problem of how to compare people who sign up for Medicaid with those who are eligible but remain uninsured. People who choose to enroll may be sicker, or they may be healthier and simply be more motivated to see doctors.

The New England Journal study reflects a recent effort by researchers to get around that problem and allow policy makers to make “evidence-based decisions,” said Katherine Baicker, an investigator on the study who served on former President George W. Bush’s Council of Economic Advisers.

“I think it’s a very significant study in part because of the paucity of studies that have really looked at health outcomes of insurance coverage,” said Karen Davis, the president of the Commonwealth Fund, a nonpartisan research foundation. “Actual mortality studies are few and far between. This is a well-done study: timely, adds to the evidence base, and certainly should raise concern about the failure to expand Medicaid coverage to people most at risk of not getting the care that they need.”

A Republican-appointed official calling this “evidence based”- will it be enough? Probably not. But the evidence is still there:

“So often you hear, ‘Oh well, poor people just shoot each other, and that’s why they have higher mortality rates,’ ” said Diane Rowland, executive vice president of the Kaiser Family Foundation, a nonprofit group. “In the midst of many claims about what Medicaid does and doesn’t do, it actually shows that it cannot only be beneficial for health, but in preventing some of the premature deaths of the uninsured.”

Janet M. Currie, director of the Center for Health and Well-Being at Princeton, said the new study, combined with the Oregon research, should help transform the Medicaid debate into one about dollars, rather than over whether covering poor people improves health.

“This says, well there is benefit to giving people insurance,” Dr. Currie said. “Maybe you don’t want to pay the cost, but you can’t say there’s no benefit.”