In a study reported in JAMA Oncology, Malinowski et al found that Medicaid expansion resulted in a reduction in the racial and ethnic disparities in mortality among patients with de novo stage IV breast cancer.

As stated by the investigators, “Patients who are uninsured and belong to racial and ethnic minority groups or have low socioeconomic status have suboptimal access to health care, likely affecting outcomes. The association of the Affordable Care Act’s Medicaid expansion with survival among patients with metastatic breast cancer is unknown.”

Study Details

The study used data from the National Cancer Database on patients diagnosed with de novo stage IV breast cancer between January 1, 2010, and December 31, 2016, residing in states that underwent Medicaid expansion on January 1, 2014. The preexpansion period was January 1, 2010, to December 31, 2013; the postexpansion period was January 1, 2014, to December 31, 2016. Patients in racial and ethnic minority groups were combined for comparison with White patients. Multivariate analysis was adjusted for age, comorbidity, breast cancer subtype, hospital transfer, geographic region, facility type, and facility volume.

Key Findings

Among 9,322 patients included in the analysis, 5,077 were diagnosed in the preexpansion period and 4,245 were diagnosed in the postexpansion period. The racial/ethnic minority group consisted of 2,545 patients (27.3%), including 500 (5.4%) Hispanic (any race) patients; 1,515 (16.3%) non-Hispanic Black patients; and 530 (5.7%) non-Hispanic “other” patients. The latter category consisted of 25 (0.3%) American Indian or Alaskan Native patients, 357 (3.8%) Asian or Pacific Islander patients, and 148 (1.6%) patients of unknown status. A total of 6,777 patients (72.7%) were White.

In the preexpansion period, patients in racial/ethnic minority groups had significantly poorer overall survival vs White patients (adjusted hazard ratio [HR] = 1.22, 95% confidence interval [CI] = 1.10–1.35, P < .001). In the postexpansion period, no significant difference was observed (adjusted HR = 0.96, 95% CI = 0.86–1.08, P = .51).

For the preexpansion vs postexpansion periods, adjusted 2-year mortality decreased from 40.6% to 36.3% among White patients and from 45.6% to 35.8% among racial/ethnic minority patients (adjusted difference in difference [DID] = −5.5%, 95% CI = −9.5% to −1.6%, P = .006).

Among patients in the lowest income quartile, racial/ethnic minority patients had significantly poorer overall survival vs White patients in the preexpansion period (adjusted HR = 1.28, 95% CI = 1.01-1.61) and significantly better survival in the postexpansion period (adjusted HR = 0.75, 95% CI = 0.59-0.95). Among these patients, racial/ethnic minority group patients exhibited a greater reduction in adjusted 2-year mortality vs White patients (from 47.9% to 35.4% vs from 44.4% to 44.7%; adjusted DID = −12.8%, 95% CI = −22.2% to −3.5%, P = .007).

The investigators concluded, “In this cross-sectional study, survival differences observed between patients of racial and ethnic minority groups and White patients in the preexpansion period were no longer present in the postexpansion period. A greater reduction in 2-year mortality was observed among patients of racial and ethnic minority groups compared with White patients. These results suggest that policies aimed at improving equity and increasing access to health care may reduce racial and ethnic disparities in breast cancer outcomes.”

Mariana Chavez-MacGregor, MD, MSc, of the Department of Health Services Research and the Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, is the corresponding author for the JAMA Oncology article.

Disclosure: This study was supported by grants from the National Cancer Institute, Susan G. Komen, and others. For full disclosures of the study authors, visit jamanetwork.com.