All you ever wanted to know about the research on health insurance and health -- and more
I think I've said quite enough on the question of whether health-care insurance reduces the risk of death. But one of the first things I did when looking into the subject was call Stan Dorn, the author of the Urban Institute study (pdf) that estimated 18,000 people died in 2006 because they didn't have health-care insurance. At the time, he said he was writing a response of his own, and would be in touch when he finished. Last night, he sent it along. It follows in full, and serves as a good introduction to the literature on this topic.
I have a few additional comments explaining why Megan McArdle’s article does not effectively refute the substantial evidence linking health insurance and mortality. She fairly characterizes as “a trifle elderly” 1993 and 1994 studies that the Institute of Medicine (IOM) used in 2002 to calculate that 18,000 adults died in 2000 because they lacked health insurance. However, McArdle completely ignores the IOM’s 2009 follow-up report finding that “the body of evidence on the effects of uninsurance on adults’ health has strengthened considerably since 2002. Numerous studies have addressed some of the methodological shortcomings of past research… The quality and consistency of the recent research findings is striking.”
Testifying to Congress last year on behalf of the IOM, John Ayanian, a professor of medicine and health care policy at Harvard Medical School, reaffirmed, “Uninsured adults are 25 percent more likely to die prematurely than insured adults overall, and with serious conditions such as heart disease, diabetes or cancer, their risk of premature death can be 40 to 50 percent higher.” The conclusion that uninsurance increases risk of death by 25 percent was the basis of IOM’s 2002 finding of 18,000 deaths resulting from a lack of health coverage as well as our 2008 updating of IOM’s calculations.
Research on the link between mortality and insurance goes far beyond the few studies discussed by McArdle. The IOM conducted rigorous, comprehensive literature reviews in both 2002 and 2009. The first report described 19 peer-reviewed journal articles finding a statistically significant relationship between insurance status and mortality, compared to 5 that found no such relationship. The 2009 update described 30 additional studies that found a robust link between insurance status and health outcomes (including mortality), compared to 9 that found no such link.
The IOM observed that insurance especially matters for adults with chronic illness, who comprise 40 percent of the uninsured: “health insurance is clearly most beneficial for adults who need medical attention, particularly for adults with common chronic conditions or acute conditions for which effective treatments are available.” Both IOM reports cited abundant research finding that the uninsured with chronic health problems receive later diagnoses and less care, so a lack of insurance coverage substantially increases mortality rates among cancer patients, heart disease patients, older adults, and hospitalized patients in general.
Recent research discussed in the 2009 IOM report imposed tight controls that addressed the methodological challenges raised by McArdle. And several noteworthy studies, both before and after the 2009 report, took advantage of “natural experiments” to isolate the effects of health coverage on health status and mortality:
1) When California terminated Medicaid coverage for childless adults in 1982, “excess deaths [for hypertensive patients] were evident within 6 months of losing insurance, and the estimated risk of dying was increased by 40%.” Link.
2) When New Jersey eliminated its subsidies of hospital care for the uninsured in 1994, death rates among the hospitalized uninsured rose by 41 to 57 percent, while such rates were unchanged in other states. Link.
3) When the near-elderly uninsured receive Medicare, they experience significant improvements in their control of cardiovascular disease and diabetes, fewer declines in health status, and greater overall health. Further, death rates among acutely ill, hospitalized patients decline by 20 percent when people turn 65 and qualify for Medicare, as noted in your post on Friday afternoon. (The latter effect is not limited to the uninsured gaining coverage, however.)
4) The uninsured in severe automobile accidents receive 20 percent less care than the insured and die at rates 39 percent higher.
As found by the IOM’s literature reviews, the research evidence is not unanimous. For example, Richard Kronick’s solid study, referenced by McCardle, found no relationship between mortality and health insurance status. However, the main point of Kronick’s study is that some of the earlier research may have overstated the effect of insurance on mortality by omitting important variables. 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.
After conducting thorough reviews of the research, IOM in 2002 and 2009, McWilliams in 2009, and Hadley in 2003 all concluded that the clear preponderance of findings from well-designed studies strongly link insurance coverage and mortality rates. McCardle erred by presenting the Kronick study as the gold standard for research on this issue to the exclusion of all studies published since 1994 that go against her argument.
Of course, the number of adults who die because they lack health insurance cannot be defined with absolute precision. Our earlier report found that improving the IOM’s methodology would increase the number of estimated deaths by more than 15 percent. And a recent Harvard Medical School study concluded that, because health care now controls disease more effectively than in the past, the lack of health insurance increases mortality by 40 percent, rather than the 25 percent estimate used by the IOM and our earlier study.
The mortality estimates reported by the IOM in 2002, updated in our 2008 report, are best viewed as indicating the likely magnitude of loss of life that results from tens of millions of Americans lacking health coverage. The exact number of fatalities may be somewhat higher or lower, but it is surely quite large.
At bottom, McCardle suggests that health is not crucially affected by the access to health care that insurance provides. I doubt that many of us fortunate enough to have health insurance would drop coverage based on the strength of her arguments.
Posted by: Kew100 | February 16, 2010 7:37 AM | Report abuse
Posted by: jkaren | February 16, 2010 9:24 AM | Report abuse
Posted by: reader44 | February 16, 2010 9:54 AM | Report abuse
Posted by: wisewon | February 16, 2010 10:58 AM | Report abuse
Posted by: CommonSense61 | February 16, 2010 11:05 AM | Report abuse
Posted by: pjcafe | February 16, 2010 12:35 PM | Report abuse
Posted by: curmudgeonlytroll | February 16, 2010 12:40 PM | Report abuse
Posted by: jnewman418 | February 16, 2010 1:23 PM | Report abuse
Posted by: Dollared | February 16, 2010 2:25 PM | Report abuse
Posted by: WmOckham | February 16, 2010 4:41 PM | Report abuse
Posted by: stan_1036 | February 16, 2010 10:26 PM | Report abuse
Posted by: MiltonRecht | February 17, 2010 12:43 AM | Report abuse
Posted by: nylund | February 17, 2010 2:34 AM | Report abuse
Posted by: chase-truth | February 17, 2010 8:00 AM | Report abuse
Posted by: WmOckham | February 17, 2010 9:39 AM | Report abuse
Posted by: Jimmy1920 | February 17, 2010 2:06 PM | Report abuse
The comments to this entry are closed.