Unpacking Health Insurance’s Impact on Mortality

Kronick aimed for his research to illuminate the critical role of insurance in life and death, hoping to shift the national dialogue around this issue. His perspective was clear, particularly as he was about to step into a health policy role in the Obama administration, where he would help implement the Affordable Care Act.

However, the findings didn’t align with his expectations, leading him to contemplate whether to suppress the results.

In his 2009 study, published in the journal Health Services Research, Kronick found “little evidence” to support the idea that expanding health insurance would significantly reduce death rates in the U.S. He challenged a frequently referenced earlier study by the Institute of Medicine, which suggested that lack of insurance caused 18,000 excess deaths annually—a claim Kronick deemed “almost certainly false.”

“I was acutely aware of the political challenges,” Kronick remarked recently. Yet, as a scientist, he felt a responsibility to present the evidence clearly.

It would take more than ten years for stronger evidence to emerge linking health insurance to saved lives, and researchers still grapple with the underlying reasons.

At the time, Kronick’s inability to establish a clear connection between insurance and mortality reflected the findings of several other studies. While uninsured individuals tended to pass away sooner, pinpointing causation proved elusive, given the myriad other influencing factors. This topic is surprisingly intricate; in fact, some research indicates that uninsured people might live longer, potentially due to fewer health issues among those who choose to forgo insurance.

Other problems, it seems, have been resolved. Research consistently indicates that having health insurance reduces the risk of medical debt or bankruptcy.

At that moment, however, there was still no conclusive evidence linking insurance to mortality rates.

Without clear results, the national discussion intensified. If insurance didn’t significantly improve health outcomes, did it hold any real value?

“False ‘The People Will Die’ Claim,” read a headline from the Mercatus Center, a libertarian think tank. Fact-checking website PolitiFact referenced Kronick’s findings to challenge claims made by lawmakers, such as the assertion that 22,000 Americans die annually from lack of health insurance. In a 2017 town hall, Rep. Raul R. Labrador stated, “No one is going to die because they don’t have access to health care.”

The Affordable Care Act, enacted despite ongoing questions regarding insurance’s effect on mortality, unexpectedly offered researchers a chance to conduct a near-experimental analysis of health insurance across a diverse group of Americans.

The Supreme Court ruled that the ACA’s Medicaid expansion was optional for states—about half opted out. This created an opportunity for researchers to observe insurance effects in real time.

“We discussed how a poor Medicaid expansion decision could have dire real-world consequences, but it would also be a gold mine for researchers,” Kronick noted.

Research continued to progress rapidly.

Benjamin Somers, a health economist and physician at Harvard’s T.H. Chan School of Public Health, co-authored a 2019 review that examined the ACA’s health outcomes. The studies, while not unanimous, revealed notable patterns.

One study estimated that mortality rates among older adults in states that expanded Medicaid decreased by 8 percent, resulting in approximately 19,200 fewer deaths in the first four years of the ACA. Another study found that states expanding dependent exemptions saw a reduction in disease-related deaths among young adults by about 3 to 6 percent.

“There’s stronger evidence for this than for many accepted conclusions,” Somers commented in an interview.

Then, in 2017, the IRS inadvertently conducted a randomized experiment by mailing letters to around four million taxpayers, who had incurred penalties for not purchasing health insurance. These letters recommended that they obtain health insurance.

However, about 15% of these taxpayers did not receive letters, creating an unintentional control group. Researchers were interested in the outcomes for individuals who started using insurance after receiving the letter. Within this newly insured group, mortality rates over the subsequent two years were markedly lower for those aged 45 to 64.

“After the IRS investigation, my doubts were resolved,” Somers declared. “There is no longer any doubt in my mind.”

Jacob Goldin, one of the IRS study authors and a law professor at the University of Chicago, remarked that the design of the study “boosts our confidence in assessing causality.” He pointed out that the reasons behind insurance’s association with lower mortality remain unclear. It might motivate individuals to seek medical help sooner for ambiguous health issues that could be life-threatening. Additionally, it could facilitate access to preventive care and essential medications.

“We’re not entirely sure why this effect occurs to the extent that it does,” Goldin admitted.

Researchers are also puzzled by why insurance appears to influence mortality in ways that defy expectations.

A 2010 study revealed that uninsured gunshot victims experienced significantly higher in-hospital mortality rates compared to their insured counterparts. This difference couldn’t be traced to injury severity, demographics, or quality of medical care, as both groups had similar rates of receiving emergency treatment. The researchers theorized that insurance coverage may correlate with various social determinants of health.

A 2022 study reflected similar findings concerning car accident victims in emergency rooms, where authors noted difficulties in explaining their observations. They hypothesized that the higher mortality rates among uninsured victims could stem from riskier behavior or older, less safe vehicles resulting from financial limitations.

As questions regarding the effect of insurance on mortality persisted, these studies seemed to represent significant outliers.

This year, a major new study rigorously evaluated the state of health insurance and mortality research.

A 2025 Annual Survey of Public Health study found compelling evidence supporting the conclusion that health insurance contributes to improved health outcomes. It emphasized the challenges of establishing clear correlations due to the rarity of deaths, but concluded that current evidence meets the necessary benchmarks.

Though the study didn’t delve into why insurance seems to save lives, it found the effect strongest among adults aged 45 and older, with some impact observed among younger adults, too.

“This is substantial,” remarked Helen Levy, co-author of both reviews, and a professor at the University of Michigan’s Institute for Social Research. “We have confirmation that health insurance saves lives. It’s time to accept this as fact.”

Yet, this finding has yet to be fully embraced in ongoing political discussions.

At a recent town hall in Iowa, when an audience member warned that proposed cuts to Medicaid could lead to deaths, Sen. Joni Ernst (R-Iowa) dismissively replied, “Well, we’re all going to die.”