But the IOM revisited the issue in 2009 and confirmed that their conclusions were correct. The lack of health insurance does contribute to an elevated risk of death.
You can read the 2009 study here:
http://www.nap.edu/openbook.php?record_id=12511&page=1The Institute of Medicine's results were confirmed by a recent Harvard Medical school study (unfortunately I can't find the entire study - only the abstract)
http://ajph.aphapublications.org/cgi/content/short/99/12/2289And you can read a short summary of the results here:
http://voices.washingtonpost.com/ezra-klein/2010/02/all_you_ever_wanted_to_know_ab_1.htmlThe above link contains this critique of Kronick's methodology:
"Kronick’s study had its own problems because, as his paper alludes, he was not able to address a critically important methodological issue—namely, that people in poor health are more likely to seek health insurance, which obscures any positive relationship between health insurance and health status. Studies that adjust for this factor have found a statistically and quantitatively significant relationship between lack of insurance and increased mortality risk. "