Medicaid Expansion Associated with More Thyroid Cancer Diagnoses

States that have expanded their Medicaid coverage also saw an uptick in the number of thyroid cancer diagnoses both for Medicaid recipients and the state’s overall population.

Results of this study, published in the Sept. 16 JAMA Surgery, show that thyroid cancer joins the long list of other cancers affected by Medicaid expansion. Broadening the government program has already been associated with increased and earlier detection of breast, colorectal, lung, and cervical cancers.

“The overall incidence of thyroid cancer increased more in Medicaid expansion states compared with non-expansion states, with a disproportionate increase among Medicaid patients,” wrote the team led by Ari Schuman, M.D., an otolaryngology resident at Baylor College of Medicine.

Expansion of the Medicare program began to occur in 2014 when the Affordable Care Act permitted states to increase the household income limit to qualify for the program from 40 percent above the federal poverty line to 138 percent. Since then, those states have seen improvements not only in cancer detection rates, but also in mortality rates.

To look at how Medicare expansion specifically affected thyroid cancer, the team examined data from 246,296 patients who received a diagnosis of a well-differentiated thyroid cancer between 2010 and 2016. They analyzed the differences in thyroid cancer incidence rates for both states that expanded coverage and those that did not.

Based on that evaluation, they found that the number of thyroid cancer cases increased among adults with Medicaid insurance in all states. But, expansion states also saw case numbers rise among adults without Medicaid coverage, as well as the overall population as whole.

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For states that expanded coverage, the number of thyroid cancer cases per 100,000 Medicaid beneficiaries rose from 3.2 in 2010 to 2012 to 5.6 in 2014 to 2016. For those without Medicaid, it jumped from 16.7 to 17.5 during those time periods, and the overall population rose from 15.9 to 16.3.

Changes for the overall population in states that did not expand coverage were not significant, but there was an increase in incidence for Medicaid recipients – 1.6 cases in 2010 to 2012 to 2.0 in 2014 to 2016.

Schuman’s team also looked at the change in the percentage of adults with thyroid cancer covered by Medicaid during the entire study period. States with expanded coverage saw a 5.6-percent rise in these covered adults, increasing from 7.3 percent in 2010 to 2013 to 12.9 percent in 2014 to 2016. States with no expansion saw a minimal bump – 4.4 percent to 4.5 percent.

Overall, the authors said, they found a 5.5-percent absolute difference in the number of adults with thyroid cancer who also had Medicaid coverage between the states that expanded and those that did not.

The team also said these changes likely did not point to any rise in over-diagnosis.

“Increased coverage could lead to increased incidence by over-diagnosis,” they said. “However, our analysis showed stable size among Medicaid enrollees, indicating no increase in over-diagnosis.”

The team did note that the National Cancer Database from which they gathered their information also includes details about pediatric patients, but they did not include it in their analysis. In addition, if a patient had both Medicare and Medicaid coverage, they were considered to be a non-Medicaid recipient. Even with these limitations, the team said, their results point to positive use of the healthcare system.

“Our data showed that Medicaid expansion was associated with an increase in thyroid cancer diagnosis among Medicaid enrollees without a change in tumor size, suggesting appropriate health care utilization,” they said.