Health insurance reduces deaths, new Massachusetts study shows

Giving more people health insurance could save tens of thousands of lives nationwide in the coming years, a new analysis of data from Massachusetts, whose trailblazing reforms became the model for President Obama’s health law, suggests.

Throughout the national debate over the Affordable Care Act, critics of the law have questioned whether expanding coverage actually results in better health. The new analysis by researchers at the Harvard School of Public Health, Brigham and Women’s Hospital and the Urban Institute adds to the growing evidence that health coverage does make people healthier.

Mortality rates in Massachusetts measurably improved compared with similar places around the country after the state began guaranteeing its residents health coverage in 2006, the researchers found.

The study, published Monday in the Annals of Internal Medicine, also implicitly provides a warning that existing gaps between states in how healthy their populations are may widen in coming years, as some states take advantage of federal money to guarantee health coverage to their residents while others do not.

About half the states, including most of those with the worst health, have decided not to expand their government Medicaid programs under the law, leaving millions of their residents without coverage.

“You have to be very careful extrapolating from any one state,” said Dr. Benjamin D. Sommers, lead author of the study. “But this really does look like it is health reform” that has led to the improvements in Massachusetts.

“There is a change happening in Massachusetts that is not happening elsewhere.”

Sommers, a researcher at Harvard, has been a part-time advisor to the U.S. Department of Health and Human Services, but the research was conducted independently.

Eight years ago, Massachusetts became the first state in the nation to create a system of universal coverage, guaranteeing its poorest residents Medicaid and providing government subsidies to help moderate-income residents get insurance on a state marketplace where insurers could not turn away the sick.

That structure became the foundation for the Affordable Care Act, which Obama signed in 2010.

Previous research has shown this system increased access to care and reduced the uninsured rate in Massachusetts, which is the lowest in the nation, at less than 5%.

A similar trend is emerging nationally, as surveys indicate millions have gained coverage since state marketplaces created by the federal law opened in October. A nationwide Gallup poll released Monday showed the percentage of working-age adults without coverage dropped from 18% last fall to 13.4% in April.

But the law’s critics continue to question the effect the expansion will have on Americans’ health.

Many point to research conducted on Oregon’s expansion of Medicaid in 2008. That study found people who gained coverage made little progress controlling their cholesterol and blood pressure, compared with low-income Oregonians without Medicaid. The researchers scrutinizing Massachusetts’ experience looked at a longer-term — and arguably more consequential — measure of health: mortality.

That is important, said Katherine Baicker, a health economist at Harvard and former Bush administration official who has been studying Oregon and also co-authored the Massachusetts study. “Studies like this one can take advantage of both longer time frames and larger sample sizes,” she said.

Unlike in Oregon, the researchers did not have a natural control group of state residents who did not get health coverage. To establish a control group, they compared Massachusetts with 513 counties around the country with similar demographics, poverty rates and rates of health coverage.

They then analyzed what happened to mortality rates in Massachusetts and the control group in the five years before and after the state enacted its reform.

Overall, mortality rates declined 2.9% in Massachusetts after the reform, compared with the control group. That suggests one death was prevented for every 830 people who gained coverage, according to the study.

“These are really important findings,” said Sara Collins, vice president at the Commonwealth Fund, a nonpartisan research foundation that studies healthcare systems. “We already know people with health insurance have a very different quality of life. … This study provides convincing evidence that increasing the number of people with insurance leads to lower rates of mortality.”

Importantly, the Massachusetts researchers found the reduction was even more pronounced in deaths from diseases that are considered treatable with good access to medical care. So-called healthcare-amenable mortality fell 4.5% in Massachusetts, compared with the control group.

Researchers also found reductions in mortality were most pronounced in Massachusetts counties with lower incomes and lower insurance coverage before reform, another indication that the insurance expansion likely had an effect.

The researchers saw no evidence of a decline in mortality among elderly Massachusetts residents, who, like their counterparts nationwide, already had guaranteed coverage through the federal Medicare program.

The authors cautioned that the health gains in Massachusetts could be explained by some other factors that they couldn’t identify.

And they warned that many other states do not have Massachusetts’ healthcare advantages. In addition to having broader insurance coverage, the state also has a large supply of primary care physicians, a record of tracking quality and a civic tradition of working to improve health.

The authors nonetheless concluded the prospects for improvements in health nationwide are good: “While this analysis cannot demonstrate causality, the results offer suggestive evidence that the Affordable Care Act — modeled after the Massachusetts law — may impact not only coverage and access but also mortality.”