Updates, corrections and clarifications.
(Friday, 8/14/09) I've removed the claim about medical costs being the primary driver of bankruptcy in the US. It seems there are two versions of this study, both done by the same researchers. The earlier version, published in Health Affairs in 2005, was problematic. The authors seem to have published a revised version based on data from 2007 this month in The American Journal of Medicine, and I'd like to look further into it before I go with their information.