Well - it's always good to cast a critical eye on studies - but I don't see why you call this a BS study- especially since you provide no proof of this retort.
From the study methods:
Woolhandler and her colleagues surveyed a random sample of 2,314 people who filed for bankruptcy in early 2007, looked at their court records, and then interviewed more than 1,000 of them. They concluded that 62.1 percent of the bankruptcies were medically related because the individuals either had more than $5,000 (or 10 percent of their pretax income) in medical bills, mortgaged their home to pay for medical bills, or lost significant income due to an illness. On average, medically bankrupt families had $17,943 in out-of-pocket expenses, including $26,971 for those who lacked insurance and $17,749 who had insurance at some point.
So it's not as you stated - that they "just' had medical bills. Rather - from interviews with the affected families and a review of their financial situations - it appears that medical costs were a major, if not defining element of bankruptcy.
You are referring to a later study that also was designed to be misleading. 1st, they looked at filings in 2007, when bankrtupcies were still way down from their historical trend. When the 2005 bankruptcy reform law was coming down the pipe, lots of people rushed to file Chapter 7's before the law changed because they didn't want to get stuck with the new law's onerous requirements. So a lot of potential bankruptcies from the latter part of the 2000's were brought forward. That combined with the deterrent effect of the new bankruptcy law resulted in many fewer filings, and the ones that did file were more likely to be sudden onset. So for people truly thrown into bankruptcy by a medical issue, you would expect the percentage to be higher in 2007 than 2001 because so many "optional" bankruptcy filings didn't take place because of the new law. That is what Warren et all found even using their bullshit definition, and they screamed and hollered about this huge spike in medical bankruptcies, from 50% of filings in 2001 to 62.1% of filings in 2007. Even if you accepted their bullshit numbers as accurate, the 62.1%in 2007 still means a much smaller number of medical bankruptcies were filed in 2007 than in 2001 because that is 62.1% of a much smaller number of filings. So if you were worried about medical bankruptcies and the impact of insurance, Warren's study would indicate the problem was getting better not worse.
Of course the 70% number is still bullshit. Probably the best indication of that is taht the people filing bankruptcy disagreed with it. The people that filed would presumably be pretty down and would love to point to something out of control as causing their bankruptcy, but only 30% claimed they filed because of medical reasons.
Another good indication taht they are doing advocacy and not research is that if you really wanted to use this study to argue for gov't subsidized or provided health insurance (as Warren did), you wouldn't include people who"lost significant income due to an illness." If anything, you would use that to argue for more/broader short term disability insurance. Including people who went bankrupt because they coudln't work makes the study mostly useless for arguments about health insurance, which won't stop the loss of income.
They also still have laughably low limits to qualify as a medical bankruptcy. $5k or 10% of gross income in medical bills? Someone making $100k a year having $5k in medical bills is not bankrupt because of medical bills. Neither is somebody making $50k. And while a $2500 medical bill while earning a $25000 salary would be tough, it can't be the cause of a bankruptcy if they also have a $15,000 car note.
The average debts is also probably chosen to be misleading, as median would give a much better indicator, as each person with a true medical catastrophe is going to influence the average disproportionately to each person with a manageable medical issue.