ANAHEIM, California — Most heart attack and stroke patients without health insurance take a devastating financial hit from hospital bills, according to a study conducted before Americans could start getting coverage under the Affordable Care Act.

Median hospitalization charges among uninsured recent legislative push is essentially pushing us back in time to before the ACA was in place, said Rohan Khera, M.D., the study’s lead researcher and a cardiology fellow at UT Southwestern Medical Center in Dallas. The findings were presented Monday at the American Heart Association’s Scientific Sessions and simultaneously published in Circulation.

Using hospital data from patients ages 18 to 64 from 2008 to 2012, researchers found that 15 percent of patients hospitalized for heart attacks and strokes did not have health insurance. (The first open enrollment season of the Affordable Care Act was in 2013.)

Most of the uninsured — 85 percent of heart attack patients and 75 percent of stroke patients — faced “catastrophic” costs. These are costs exceeding 40 percent of annual household income after removing food costs, which are considered essential, according to Khera.

Heart attack hospitalizations cost a median $53,384 and strokes cost $31,218, according to the study. The resulting catastrophic costs make it difficult for uninsured patients to keep up with basic living expenses such as transportation and housing, according to researchers.

Catastrophic health expenses were most likely among patients living in urban areas who had low household incomes and additional health problems, according to the study.

In a separate study presented Monday, the same research group evaluated costs of heart bypass surgery, also known as a coronary artery bypass graft.

Using the same data and time frame, researchers found that 9 percent of bypass patients were uninsured. Of those, 83 percent faced catastrophic costs.

Bypass surgery costs substantially more than heart attack and stroke, with a median hospital cost of $85,891 to $177,546, the study showed. During the procedure, surgeons reroute blood around clogged heart arteries.

Neither study factored in additional costs following hospitalization, such as loss of productivity from missing work or ongoing medical care and drugs, which may have further financial consequences, Khera said.

“It’s safe to assume these recurring costs after hospitalizations and recovery from cardiac events would contribute to greater likelihood of bankruptcy,” said Jonathan C. Hong, M.D., lead author of the bypass study and a cardiac surgery resident at the University of British Columbia in Vancouver, Canada.

Khera said he was troubled by the prospect of the ACA being repealed, which could lead to more catastrophic costs.

“Until there is universal coverage for those without resources,” the authors wrote, “catastrophic illness will remain a disabling financial threat to many Americans.”

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