Medicaid Expansion Associated With Decrease in Mortality Among Certain Cancers


Analysis demonstrates affordable access to care may be a factor in patient outcomes

In a study of 523,802 patients recently given a diagnosis of breast, colorectal, or lung cancer, investigators linked an expansion of Medicaid benefits with decreased mortality.

Following the passage of the Affordable Care Act in March 2010, Medicaid eligibility was expanded to include nonelderly adults with incomes at or below 138% of the federal poverty level. By March 2020, 36 states and the District of Columbia were able to expand Medicaid coverage to approximately 20 million US residents.

Previous studies had demonstrated that Medicaid expansion was associated with fewer uninsured patients, increased screenings, and diagnosis at earlier stages among patients with cancer, with some additional mixed results on improving racial and socioeconomic disparities. However, the association between Medicaid expansion and mortality among patients with cancer remained unclear.

For this reason, a study published in JAMA Network Open sought to assess this association further, to determine whether Medicaid expansion was associated with improved mortality among patients with cancer.

The authors conducted a quasi-experimental, difference-in-differences (DID), cross-sectional, population-based study in order to analyze data from patients in the National Cancer Database, of which 73.6% were women (mean age, 54.8 years), with breast, lung, or colorectal cancer. All the patients included in the study analysis had received diagnoses between January 1, 2012, and December 31, 2015, with this diagnosis being their first.

The cancers were selected by the authors because they are common, easy to screen, and treated for cure in the nonmetastatic setting, which implies that patient access to treatment could potentially affect patient outcomes.

Additionally, the authors defined expansion states as early as January 2014 in order to compare them with the nonexpansion group. This differentiation was made because, although some states officially expanded on January 1, 2014 through a waiver process, a smaller subset had joined the Medicaid expansion earlier. However, 24 states and the District of Columbia expanded their Medicaid programs on January 1, 2014, marking the beginning of the postexpansion period in the study’s primary analysis.

In the analysis, the authors also excluded patients in late expansion states (mid-2014-to-2018 expansion) because of an inability to determine when the expansion occurred without additional information, such as the state of residence, and insufficient postexpansion data.

In the data analysis performed between January and May 2020, the researchers assessed 273,272 patients with invasive breast cancer; 111,720 patients with colorectal cancer; and 138,810 patients with lung cancer. Of these patients, 55.2% lived in Medicaid expansion states, and 44.8% lived in nonexpansion states.

The results from the Kaplan-Meier adjusted survival curves and an adjusted Cox regression model demonstrated a small but significant mortality improvement in expansion states when compared with nonexpansion states. The Kaplan-Meier curves showed absolute survival difference to be 0.4%, meaning that 1 death would be prevented 4 years after cancer diagnosis if 250 patients with cancer gain coverage.

From the preexpansion to postexpansion periods, the researchers observed a 2.0% decreased hazard of death among the expansion group. If this 2.0% reduction in mortality were achieved in all Medicaid expansion states, then 1384 lives could be saved annually. In contrast, the researchers found that mortality remained unchanged in nonexpansion states during the same period.

For the DID ratio that compared the hazard ratio (HR) in nonexpansion states with expansion states, the researchers observed a DID HR of 1.03, demonstrating that the improved mortality in expansion states was significantly different from the unchanged mortality in nonexpansion states.

Additionally, among cancer type, similar trends were observed in expansion states versus nonexpansion states. For example, although mortality improved for lung cancer patients in both expansion states and nonexpansion states, the improvement was significantly greater in expansion states than in nonexpansion states. For breast and colorectal cancers, mortality was worse in both expansion and nonexpansion states, but the degree to which mortality increased was lower in expansion states, and the difference between the HRs was not significantly different for either breast cancer or colorectal cancer.

However, the researchers found that the patients who live in areas with the lowest quartile of median household income experienced only a slight decrease in mortality in expansion states over time, with no change in mortality among nonexpansion states. Among patients living in areas with the highest quartile of median household income who would be eligible if included in the Medicaid expansion, mortality was found to increase slightly within nonexpansion states and decreased slightly within expansion states. This observation demonstrated to the researchers that Medicaid expansion was not associated with a difference in mortality among patients in the lowest quartile versus the highest quartile of median household income.

Among Black patients, mortality was found to decrease slightly in expansion states but remained unchanged in nonexpansion states during the preexpansion-to-postexpansion period. For White patients, mortality was found to be slightly lower in expansion states and slightly higher in nonexpansion states. This also demonstrated to the researchers that Medicaid expansion was not associated with a difference in mortality between Black and White patients.

The investigators noted that although there were no differences in mortality changes among at-risk populations, such as Black patients and patients living in areas with the lowest quartile of income, Medicaid expansion was associated with a significant decrease in mortality in expansion states when compared with nonexpansion states.


Lam MB, Phelan J, Orav EJ, Jha AK, Keating NL. Medicaid Expansion and Mortality Among Patients With Breast, Lung, and Colorectal Cancer. JAMA Netw Open. 2020;3(11):e2024366. doi:10.1001/jamanetworkopen.2020.24366

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