1. Fuerst, Mark L.

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Cancer mortality rates declined more in states that adopted Medicaid expansion following passage of the Affordable Care Act (ACA) than in states that did not, according to a new nationwide study.

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After congressional approval in 2010, 20 million Americans gained insurance under the ACA. Granting states permission to expand Medicaid coverage to more people was one of the key components of the ACA. The law expands Medicaid coverage for most low-income adults to 138 percent of the federal poverty level. Many states formally adopted Medicaid expansion in January 2014. Those states that participated saw large increases in Medicaid enrollment, including people with incomes near the poverty level who were newly eligible, as well as those who had been eligible but had not enrolled previously.


"This is the first study to show a directly measured cancer survival benefit from Medicaid expansion," said lead author Anna Lee, MD, MPH, Radiation Oncology Fellow at Memorial Sloan Kettering Cancer Center (MSK) in New York. "We now have evidence that Medicaid expansion has saved the lives of many people with cancer across the United States."


Lee presented the results of the study at a press briefing before the 2020 ASCO Annual Meeting (Abstract 2003).


About the Study

Using a comprehensive database maintained by the Centers for Disease Control and Prevention of all cancer deaths, states were grouped by Medicaid expansion status as of January 2015. The researchers analyzed age-adjusted cancer mortality to control for the differences in population age distribution. They established baseline trends from 1999 to 2017 and then compared age-adjusted rates between 2011 and 2013 (prior to full state expansion) and 2015 and 2017 (the period following expansion) for states that adopted Medicaid expansion and those that did not. Deaths due to cancer in patients age 65 or older were not included in the analysis, as those patients are eligible for Medicare.


Then the researchers gathered age-adjusted cancer mortality rates from each state and grouped the states into those that expanded Medicaid and those that did not. During the time period of their analysis, 27 states plus the District of Columbia had adopted Medicaid expansion, while 23 states had not.


Key Findings

Overall trends for age-adjusted cancer mortality in the United States from 1999 to 2017 showed that states that expanded Medicaid saw a 29 percent decline, falling from 65.1 to 46.3 per 100,000 individuals in that period. In states that did not expand Medicaid, rates dropped by 25 percent, from 69.5 to 52.3 per 100,000.


Specifically looking at the changes after 2014 expansion, the additional mortality benefit for states that adopted Medicaid expansion amounted to an estimated 785 fewer cancer deaths in 2017 alone. "An estimated additional 589 deaths could have been prevented if all states had expanded," Lee noted.


For the study analysis, the researchers used a statistical technique called difference-in-differences. They calculated the difference in mortality rates between the two periods for expansion and non-expansion states, and then calculated the difference between these values. The intent is to mitigate the effects of baseline population differences and other differences in access at the state level.


Comparing the mortality changes before and after ACA expansion, the difference-in-differences was -1.1 and -0.6 per 100,000 for expansion and non-expansion states, respectively. "This encapsulates the potential true benefit of Medicaid expansion at a population level," said Lee.


The researchers also looked at changes in sub-populations, including patients who were Black or Hispanic. Although there were large mortality gains during the study period for patients who were Black, no additional mortality reduction was seen in this population in states with Medicaid expansion. However, age-adjusted cancer mortality overall was consistently worse for Black patients in states without expansion than in states with expansion (58.5 vs. 63.4 per 100,000 for the expansion and non-expansion states respectively).


"Black patients have the absolute highest cancer mortality. In the Black population, the overall cancer mortality rate was improving at a greater rate than with Whites or Hispanics. This may be why we were unable to find a benefit of Medicaid expansion in this population," Lee stated.


In contrast, the greatest differential change in cancer mortality rates between expansion and non-expansion states was seen for Hispanic patients, although there was significant variation in year-to-year mortality seen in this population.


"There is a greater Hispanic population in states that have adopted Medicaid expansion, and they have almost three times the un-insurance rate as White adults," said senior author Fumiko Chino, MD, a radiation oncologist at MSK. "Our research shows that Hispanic patients with cancer may have benefited the most because they had the most to gain."


ASCO Chief Medical Officer and Executive Vice President Richard L. Schilsky, MD, commented, "This study provides needed data to understand the effects of Medicaid expansion on cancer care. Better access to quality cancer care, in this case through state expansion of Medicaid, leads to fewer cancer deaths." He noted that 30 percent of cancer deaths are among patients under age 65.


In conclusion, Lee stated: "Further studies are needed to understand how national programs and policies such as ACA can continue to improve access to care and decrease health care disparities."


Deborah Marshall, MD, MAS, Research Fellow at The Tisch Cancer Institute at Mount Sinai in New York, commented: "These data add to the growing body of evidence that Medicaid expansion improves access to care and health outcomes and, in particular, the study addresses an important gap in our understanding of whether Medicaid expansion is associated with cancer mortality and further validation is needed to understand the underlying causes of this association."


Mark L. Fuerst is a contributing writer.