Most health care consumers in America would pay fewer out-of-pocket medical costs under the eponymously named Affordable Care Act, researchers from the Rand Corporation say.

However, some people—particularly those newly insured who don’t qualify for government subsidies—may spend more of their money on health care in the near future as they begin to pay coverage premiums. Without the Affordable Care Act’s individual mandate to purchase health insurance, upheld last year by the U.S. Supreme Court as constitutional, such patients in the past would have “self-insured,” assuming the total risk for non-emergency health expenditures.

Yet, poorer Americans who were previously uninsured will likely see the biggest drop in health care spending as they gain coverage under Medicaid, the federal and state health insurance plan expanding under the new law known as Obamacare.

Examining Florida and Texas in particular, the researchers also estimated consumer spending in states choosing not to expand Medicaid programs, releasing a report on Tuesday. In states opting out of Obamacare, they said, poorer Americans without health insurance would likely see cost increases for their personal and family health care expenditures, indicating a continuing political battle over health insurance in the months and years to come.

Researcher Christine Eibner, a senior economist at the non-profit research organization, discussed the report on Tuesday. “Among the groups we studied, a clear benefit of the Affordable Care Act is that it will reduce the risk of facing catastrophic medical costs,” she said. “Consumers with the lowest incomes will see the most dramatic reductions of their risks.”

Eibner and her colleagues used a microsimulation model they say predicts the effect of health policy changes on state and national levels, including likely effects of Obamacare on out-of-pocket expenses—co-pays and deductibles—as well as overall costs including premium payments. Among the study’s findings, 11.5 million health care consumers gaining insurance through expanded Medicaid coverage will save between $34 and $1,463 per year.

Conversely, the biggest “losers” in the Obamacare cost shuffle would be people newly insured through individual coverage plans whose incomes are four times higher than the federal poverty level, a group that includes some 3.3 million Americans. These consumers would spend nearly $2,000 more per year on health care than without the controversial national health care law, paying $7,202 on average as compared to $5,368.

Most dramatically perhaps, impoverished Americans who don’t already qualify for Medicaid in states declining to join the expansion—such as Texas—would pay on average $1,831 in medical costs per year, compared to an estimated $34.

The federal government began a partial shutdown of services worldwide Tuesday as democrats and republicans continued a parliamentary battle over the new federal health law.

Source: Nowak, Sarah A., Adamson, David M., Saltzman, Evan. Effects Of The Affordable Care Act On Consumer Health Care Spending And Risk Of Catastrophic Health Costs. Rand. 2013.