In states that have expanded Medicaid availability as part of the Affordable Care Act (ACA), mortality rates for three major types of cancer are significantly lower than in states that have not expanded their Medicaid, according to findings from a new study published by Miranda B. Lam, MD, MBA, and colleagues in JAMA Network Open. Data from the study suggest that the improvement in mortality may result from cancers being diagnosed at an earlier stage in states with Medicaid expansion.

The ACA, passed in 2010, gave states the option of expanding eligibility for Medicaid to nonelderly adults with incomes at or below 138% of the federal poverty level. Previous studies involving patients with cancer have shown Medicaid expansion is associated with fewer uninsured patients, increased screening, and stage of disease diagnosis. Currently, 39 states have expanded Medicaid programs.

Miranda B. Lam, MD, MBA

“There has been little research into the impact of Medicaid expansion on cancer mortality,” said lead study author Dr. Lam, of Dana-Farber Cancer Institute, Brigham and Women’s Hospital, and Harvard T.H. Chan School of Public Health. “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.”

Study Methods and Results

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 January 1, 2014.)

“We found that Medicaid expansion was associated with a significant decrease in mortality compared to states without such expansion,” said Dr. Lam. The expansion group had a 2% decline in hazard of death from the pre- to the postexpansion period. The nonexpansion 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 were considered curable. When investigators adjusted for the stage at which cancers were diagnosed, improvements in mortality were no longer seen—whether between expansion and nonexpansion states, or between the preexpansion and postexpansion 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 health-care system for screening and timely symptom evaluation, and that can translate into better outcomes for patients,” said Dr. Lam.

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,” said Dr. Lam. “We also found that the mortality improvements occurred in both Black and White populations.”

The study authors concluded, “Among patients with newly diagnosed breast, colorectal, and lung cancer, Medicaid expansion was associated with a decreased hazard of mortality in the postexpansion period, which was mediated by earlier stage of diagnosis.”

Disclosure: The study was conducted with the support of a KL2 award from Harvard Catalyst | The Harvard Clinical and Translational Science Center (National Center for Advancing Translational Sciences, National Institutes of Health Award KL2 TR002542). For full disclosures of the study authors, visit jamanetwork.com.