According to the findings of the American Journal of Medicine, over 60% of consumer bankruptcy cases filed in 2007 were due to medical bills.  You can read the report by clicking here.  A summary of the results —

Using a conservative definition, 62.1% of all bankruptcies in 2007 were medical; 92% of these medical debtors had medical debts over $5000, or 10% of pretax family income. The rest met criteria for medical bankruptcy because they had lost significant income due to illness or mortgaged a home to pay medical bills. Most medical debtors were well educated, owned homes, and had middle-class occupations. Three quarters had health insurance. Using identical definitions in 2001 and 2007, the share of bankruptcies attributable to medical problems rose by 49.6%. In logistic regression analysis controlling for demographic factors, the odds that a bankruptcy had a medical cause was 2.38-fold higher in 2007 than in 2001.


Click here for an article in the LA Times on the subject. It would be interesting to know how the findings would change for 2008-09 with the changes in the economy.