August 23, 2018
3 min read

Medicaid expansion may decrease disparities in cancer care

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Xuesong Han
Xuesong Han

Medicaid expansion under the Affordable Care Act appeared to reduce disparities in percentage of insured patients with cancer from various sociodemographic subpopulations, according to findings from a population-based analysis.

“Disparities in the percentage of uninsured patients by race/ethnicity, census tract-level poverty and rurality were diminished or eliminated for patients in Medicaid expansion states but remained high in nonexpansion states, suggesting that Medicaid expansion may be an effective strategy in mitigating health disparities,” Xuesong Han, PhD, cancer epidemiologist and strategic director of health policy and health care delivery research at the American Cancer Society, and colleagues wrote.

The state Medicaid program expanded eligibility in 2014 under the ACA. Improved insurance eligibility may enhance access to cancer screening, diagnostic follow-up and treatment.

Previous studies have evaluated the effects of Medicaid expansion on insurance and early-stage diagnosis among patients with cancer. However, little research exists on changes in the number of uninsured patients by state and specific sociodemographic groups.

Han and colleagues evaluated changes in the uninsured rate and the percentage of early-stage diagnoses after implementation of the ACA by state and sociodemographic groups using a population-based cancer registry dataset from 40 states provided by the North American Association of Central Cancer Registries.

The analysis included 2,471,154 patients (mean age, 52.7 years; 51.4% women; 70.9% non-Hispanic white) diagnosed with first primary malignant cancer between 2010 and 2014. The sample represented 21 states that implemented Medicaid expansion (n = 1,234,156) and 19 nonexpansion states (n = 1,236,998).

Researchers stratified patients based on sex, race or ethnicity, census tract-level poverty and rurality according to residence at the time of cancer diagnosis.

Changes in the percentage of uninsured patients and early-stage diagnoses before (January 1, 2010 to December 31, 2013) to after (January 1, 2014, to December 31, 2014) Medicaid expansion under the ACA served as the primary outcome.

Compared with patients in nonexpansion states, patients in expansion states were more likely to be Hispanic (11.4% vs. 8.9%) and less likely to be black (9.4% vs. 16.7%) or reside in the lowest poverty census tracts (20.5% vs. 24.4%).

In 2014, the number of uninsured patients decreased across most states. However, decreases appeared greater among states with than without Medicaid expansion, with especially pronounced decreases among expansion states with high baseline uninsured rates.

For example, in Kentucky — an expansion state — the proportion of uninsured patients decreased from 8.3% prior to implementation of the ACA to 2.1% after implementation, for a 6.2-percentage point difference. In Tennessee, a neighboring nonexpansion state, the number of uninsured patients decreased from 9.1% to 7.6%, which reflected a 1.5-percentage point difference.


After adjusting for sociodemographic factors, analysis showed Medicaid expansion states experienced a 1.3-percentage point greater reduction in the number of uninsured patients compared with nonexpansion states (crude, 2.6 vs. 1; P < .001).

Among expansion states, minorities and individuals living in high-poverty or rural areas experienced greater decreases in uninsurance, whereas sociodemographic disparities in the number of uninsured patients remained high in nonexpansion states.

The reduction in the percentage of uninsured patients in expansion states was larger among males than females (–2.8 vs –2.4 percentage points), minority groups (non-Hispanic blacks, –4.1; Hispanics, –4 vs. non-Hispanic white, –2.3), those living in higher census tract-level poverty areas (lowest income, –4.6 vs. highest income, –1.3) and rural residents (rural, –4.3 vs. urban, –2.5).

“As a result, disparities in the percentage of uninsured patients between expansion states and nonexpansion states within each subpopulation increased, most prominently among those who were socioeconomically disadvantaged,” researchers wrote.

Researchers observed a slight, but significant, (0.4 percentage points) association between Medicaid expansion and earlier diagnosis stage among various cancer types.

Significant shifts to early-stage diagnosis in expansion states occurred for non-Hodgkin lymphoma (adjusted difference-in-differences, 1.8 percentage points) and pancreatic cancer (adjusted difference-in-differences, 1.5 percentage points).

Researchers observed a significant 2.7-percentage point decrease in early-stage diagnosis of liver cancer in expansion states compared with nonexpansion states.

For colorectal cancer, lung cancer, female breast cancer and melanoma, the number of early-stage diagnoses increased among both expansion and nonexpansion states, but the differences were not significant.

Researchers noted that even before ACA implementation, patients who resided in nonexpansion states had increased likelihood of being uninsured, as well as worse access to care, lower preventive services use and higher out-of-pocket medical costs than patients residing in expansion states.

Thus, although Medicaid expansion may reduce disparities in expansion states, between-state disparities may widen.

“The emerging widening disparity in the percentage of uninsured patients between the nonexpansion and expansion states after implementation of the ACA will likely exacerbate the inequalities in access to care and health outcomes because of differential state policies in expanding Medicaid eligibility,” the researchers wrote.

“Future studies that monitor the effect of Medicaid expansion on cancer outcomes and health disparities are warranted,” they added. – by Melinda Stevens

Disclosures: All authors report employment with the American Cancer Society, which received a grant from Merck for intramural research outside the submitted work.