The decline was steepest in counties with the highest proportions of poor and previously uninsured people. In contrast, the mortality rate in a control group of counties similar to Massachusetts in other states was largely unchanged.The researchers looked specifically at causes of mortality "amenable to health care." Those are diseases like cancers, heart disease, and other chronic serious health concerns that can be treated and that people can survive with regular medical care. Where they got it—Massachusetts—there was a 3 percent lower mortality rate than where they didn't get it.
A national 3 percent decline in mortality among adults under 65 would mean about 17,000 fewer deaths a year.
“It’s big,” said Samuel Preston, a demographer at the University of Pennsylvania and an authority on life expectancy. Professor Preston, who was not involved in the study, called the study “careful and thoughtful,” and said it added to a growing body of evidence that people with health insurance could reap the ultimate benefit — longer life.
There are a bunch of caveats that go with this, primarily that Massachusetts has a more white and more affluent population in general than most states. The control group the researchers used were people in 513 counties in 46 other states that matched pre-reform Massachusetts in terms of demography, income, and rate of insurance. But that makes for a huge data set—4 million in Massachusetts and 44 million in the control group, a large enough population to make the findings statistically significant. It was also a large enough group to get detailed enough information to look for other factors beyond health insurance. The authors didn't find any other factors that could account for this mortality drop.
Massachusetts embraced this reform, with stakeholders working hard to make it a success. In that way, it also won't be representative of the national population where some states are doing the minimum to expand access to health insurance through Obamacare. But with all those caveats, this is a big study with very good results. And those results suggest that Obamacare is going to save lives.