In the nearly year and a half since Congress passed the health care overhaul, one of the main purposes of the bill — to provide health insurance to people who lack it — has often been lost in the debate. Instead, supporters and opponents of the bill have argued over whether the bill is constitutional, and they’ve argued over whether the bill will cut medical costs more or less than the Congressional Budget Office projects.

Those are obviously important issues. But so is the fact that, unlike any other rich country in the world, the United States has tens of millions of people who do not have health insurance and therefore go without some forms of medical care.

A new study being released today, by some of the country’s top health economists, aims to estimate the effects of not having health insurance — and the effects are large.

The researchers used a lottery that the state of Oregon conducted in 2008 to determine who would become eligible to apply for a limited number of Medicaid slots. The researchers compared the health outcomes of those who won the lottery (many of whom then received insurance) and those who did not (who were more likely to remain uninsured).

The researchers have followed the subjects for only a year so far, so the paper has some clear limitations. But it nonetheless suggests that having health insurance substantially improves health. Expanding insurance does not save society money — as some advocates of preventive medicine have claimed — but it does appear to make people mentally and physically healthier.

The authors point out that the insurance in question — Medicaid — is the same one that many uninsured people will receive as part of the health care law. For that reason, among others, the paper suggests that the law is likely to improve the health and well-being of many of the uninsured.

Katherine Baicker — one of the authors and a Harvard economist who served in President George W. Bush’s administration — wrote the following to me, via e-mail:

There has been a great deal of uncertainty about how much of a difference Medicaid makes to enrollees. Some argued that Medicaid isn’t ‘good’ insurance coverage and that a Medicaid card doesn’t get enrollees much access to care. Others argued that the uninsured already have access to care through the emergency room, clinics, or charity care.

Our study shows that gaining access to Medicaid matters on a number of different dimensions, including increased access to and use of health care.

The authors also point out that the benefits of health insurance aren’t only medical. They’re financial too, as is the case with other forms of insurance. Here’s another author, Amy Finkelstein (an M.I.T. economist who has written for The Wall Street Journal opinion pages and whom I’ve written about), also via e-mail:

Health insurance isn’t just about access to health care – it’s also about protection from financial ruin. This point isn’t often discussed in the debate about health insurance expansions, but the reduction in financial strain that we found was substantial. This is important for enrollees, but it is also important for the providers who see fewer of their bills go unpaid.

Besides Ms. Baicker and Ms. Finkelstein, the paper’s authors include Jonathan Gruber (an M.I.T. economist, who has advised the Obama administration) and Joseph Newhouse (a Harvard economist who designed and ran the famous RAND Health Insurance Experiment in the 1970s and ’80s). The other authors are Sarah Taubman, Bill Wright, Mira Bernstein, Heidi Allen and members of the Oregon Health Study Group.

Excerpts from the study follow:

About one year after enrollment, we find that those selected by the lottery have substantial and statistically significantly higher health care utilization, lower out-of-pocket medical expenditures and medical debt, and better self-reported health than the control group that was not given the opportunity to apply for Medicaid.

The increase in hospital admissions appears to be disproportionately concentrated in the approximately 35 percent of admissions that do not originate in the emergency room, suggesting that these admissions may be more price sensitive.

[W]e find that insurance is associated with improvements across the board in our measures of self-reported physical and mental health, averaging two-tenths of a standard deviation improvement. These results appear to reflect improvements in mental health and also at least partly a general sense of improved well being; they may also reflect improvements in objective, physical health, but this is more difficult to determine with the data we now have available.

[I]nsurance is also associated with an increase in compliance with recommended preventive care. We look at four different measures of preventive care: blood cholesterol checks, blood tests for diabetes, mammograms, and pap tests. …[T]he results indicate … a 20 percent increase in the probability of ever having one’s blood cholesterol checked, a 15 percent increase in the probability of ever having one’s blood tested for high blood sugar or diabetes, a 60 percent increase in the probability of having a mammogram within the last year (for women 40 and over), and a 45 percent change in the probability of having a pap test within the last year (for women).

[Our] calculation suggests that insurance is associated with a $778 (standard error = $371) increase in annual spending, or about a 25 percent increase relative to the implied control mean annual spending.

Article source: http://feeds.nytimes.com/click.phdo?i=cc449c4862027e8bb8525e806cb27c6f