Medicaid expansion associated with decreased cancer mortality rates

Reviewed by Emily Henderson, B.Sc.Nov 5 2020

In states that have expanded Medicaid availability as part of the Affordable Care Act (ACA), mortality rates for three major forms of cancer are significantly lower than in states that have not expanded their Medicaid, a new study by researchers at Dana-Farber Cancer Institute, Brigham and Women's Hospital, and Harvard University shows.

Data from the study, published online today in JAMA Network Open, suggest that the improvement in mortality results from cancers being diagnosed at an earlier stage in states with Medicaid expansion. Early detection of cancer is often critical to successful treatment of the disease.

The ACA, passed in 2010, gave states the option of expanding eligibility for Medicaid - the government-funded health insurance program for low-income families and individuals - to nonelderly adults with incomes at or below 138% of the federal poverty level. Previous studies involving cancer patients have shown Medicaid expansion to be associated with fewer uninsured patients, increased screening, and stage of disease diagnosis. (Currently, 39 states have expanded Medicaid programs.)

There has been little research into the impact of Medicaid expansion on cancer mortality [the time from initial cancer diagnosis to death]. It's been thought that expansion might improve mortality by fostering earlier detection, earlier stage of diagnosis, and improved access to treatment. On the other hand, it could worsen mortality by creating an influx of newly covered patients that strains hospitals' resources."

Miranda Lam, MD, MBA, Lead Author, Dana-Farber, Brigham and Women's Hospital, and Harvard T.H. Chan School of Public Health

For the study, researchers used the National Cancer Database to track 523,802 patients across the country who were newly diagnosed with breast, lung, or colorectal cancer from 2012 through 2015. They compared mortality rates for these patients in states that expanded their Medicaid programs and those that did not. (Twenty-four states and the District of Columbia expanded their programs on Jan. 1, 2014.)

"We found that Medicaid expansion was associated with a significant decrease in mortality compared to states without such expansion," Lam remarks. The expansion group had a 2% decline in hazard of death from the pre- to the post-expansion period. The non-expansion group, by contrast, showed no change in mortality.

If the 2% reduction was achieved in all states with expanded Medicaid, then among the approximately 69,000 patients diagnosed with cancer in those states, 1,384 lives would be saved yearly, researchers calculated.

The biggest difference between the two groups was in patients whose cancers hadn't reached a metastatic stage and are considered curable. When investigators adjusted for the stage at which cancers were diagnosed, improvements in mortality were no longer seen - whether between expansion and non-expansion states or between the pre-expansion and post-expansion period. This suggests that the decline in mortality associated with Medicaid expansion is a byproduct of diagnosing cancer at an earlier stage.

"Increased Medicaid coverage may remove barriers to accessing the healthcare system for screening and timely symptom evaluation, and that can translate into better outcomes for patients," Lam comments.

The investigators also found that the decrease in mortality in Medicaid-expansion states occurred across population groups. "We were reassured to find that patients living in areas of the lowest quartile of median household income showed a modest decrease in mortality after Medicaid expansion," Lam observes. "We also found that the mortality improvements occurred in both Black and white populations."