Medical bills are behind more than 60 percent of U.S. personal bankruptcies, U.S. researchers reported on Thursday in a report they said demonstrates that healthcare reform is on the wrong track.

More than 75 percent of these bankrupt families had health insurance but still were overwhelmed by their medical debts, the team at Harvard Law School, Harvard Medical School and Ohio University reported in the American Journal of Medicine.

"Unless you're Warren Buffett, your family is just one serious illness away from bankruptcy," Harvard's Dr. David Himmelstein, an advocate for a single-payer health insurance program for the United States, said in a statement.

"Only single-payer national health insurance can make universal, comprehensive coverage affordable by saving the hundreds of billions we now waste on insurance overhead and bureaucracy."