A Romney presidency would also see more than 40 million additional Americans uninsured, the study found.
Families USA concluded that "ObamaCare" — the president's signature healthcare law — and "RomneyCare" — Romney's Massachusetts reform law — would lead to similar outcomes, but that Romney's positions as the GOP presidential nominee represent a drastic departure and place a "growing an unsustainable burden on America's families."
“Under RomneyCandidateCare," said Families USA Executive Director Ron Pollack in a statement, "middle-class families would pay comparatively much more out of pocket for their health care, and the number of uninsured Americans would skyrocket."
Families USA is a prominent Washington, D.C.-based think tank that supported healthcare reform, which Romney has called a "job-killer" and vowed to repeal.
The Romney campaign poormouthed the study.
“The Families USA ‘study’ is absurd. It assumes a fantasy world where Obamacare has actually worked," said Romney campaign spokeswoman Amanda Henneberg in an e-mail to The Hill. "But Americans aren’t buying it. They’ve have watched as provision after provision has failed, costs have skyrocketed, and Medicare has been cut by $716 billion. Today’s report undermines the important health care debate our country should be having.”
The group's report also concluded that "RomneyCandidateCare" would "significantly" change Medicare by repealing benefits created by the Affordable Care Act, hastening its insolvency and, ultimately, by partially privatizing the program.
"These are stark differences from the directions set by both RomneyCare and ObamaCare," the report states. "The choice of which direction our nation will take about these fundamentally different approaches will have a profound impact on families across America."
Read more from the report here.
Updated at 6:55 p.m.