Health coverage mediates risk for later-stage breast cancer diagnosis among minorities
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Health insurance coverage mediated almost half of upstaging at breast cancer diagnosis among a population of racial and ethnic minority women, according to results of a retrospective, cross-sectional study published in JAMA Oncology.
“We have been dedicated to research investigating the root cause of breast cancer disparities for some time now,” Naomi Y. Ko, MD, MPH, oncologist in the department of hematology and medical oncology at Boston University School of Medicine, told Healio. “Unfortunately, it has been well-studied that racial and ethnic minority populations in the United States have worse breast cancer outcomes. We are committed to finding ways to change that.”
Despite the overall positive trends in survival among women with breast cancer, not all patients have benefited equally. Compared with white women, racial and ethnic minority women are more likely to receive a late-stage breast cancer diagnosis, leading to higher mortality and morbidity and poorer overall quality of life, researchers noted.
Ko and colleagues sought to quantify the extent to which adequate health insurance is a factor in stage of breast cancer diagnosis by pooling data from the SEER database on 177,075 American women aged 40 to 64 years (mean age, 53.5 years) diagnosed with stage I to stage III breast cancer. The study population included 113,079 white women, 23,845 Hispanic women, 20,822 black women, 18,231 Asian or Pacific Islander women, and 1,098 American Indian or Alaskan Native women.
Most of the women (n = 148,124) had adequate health insurance, whereas 28,951 were uninsured or had Medicaid coverage at breast cancer diagnosis. A greater proportion of women with Medicaid or no health insurance were unmarried (58% vs. 29%) and resided in census tracts with the lowest quintiles of median income (27% vs. 19%). They also were more likely to live in the highest quintiles of percentage of adults with less than a high school education (31% vs. 18%), percentage living at less than 150% of the federal poverty level (26% vs. 17%) and percentage living in language isolation (26% vs. 19%).
Researchers used statistical mediation methods that estimated the presence of mediation and direct and indirect effects of insurance coverage through a series of regression analyses.
Risk for a more advanced stage of breast cancer (stage III vs. stages I and II) at diagnosis served as the primary outcome.
Results showed a larger percentage of women who were uninsured or receiving Medicaid received a diagnosis of locally advanced (stage III) breast cancer compared with women with adequate health insurance (20% vs. 11%).
Black (OR = 1.46; 95% CI, 1.4-1.53), American Indian or Alaskan Native (OR = 1.31; 95% CI, 1.07-1.61) and Hispanic (OR = 1.35; 95% CI, 1.3-1.42) women had higher odds of having locally advanced disease at diagnosis than white women.
After researchers adjusted for health insurance coverage and other socioeconomic factors, they found the associations between race/ethnicity and risk for locally advanced breast cancer were attenuated for black (OR = 1.29; 95% CI, 1.23-1.35), American Indian or Alaskan Native (OR = 1.11; 95% CI, 0.91-1.35) and Hispanic (OR = 1.17; 95% CI, 1.12-1.22) women.
Moreover, almost half of racial differences in the risk for locally advanced disease were mediated by health insurance coverage among black (45%), American Indian or Alaskan Native (46%) and Hispanic (47%) women.
The researchers noted several study limitations associated with use of SEER data, including the fact that the women sampled may not be reflective of the general population of women in the United States.
“We have always felt that insurance coverage could be a significant factor in breast cancer disparities, and our findings suggest that more than half the upstaging at breast cancer diagnosis seen in racial/ethnic minorities is mediated by insurance,” Ko told Healio. “We are dedicated to research that improves our understanding of the root causes for breast cancer disparities, such as the direct and indirect cost of inadequate insurance, poor access to care, delayed treatment, lack of clinical trial enrollment and more. Overall, we strive to identify modifiable factors across the cancer continuum that may help reduce breast cancer disparities.” – by Jennifer Southall
For more information:
Naomi Y. Ko, MD, MPH, can be reached at Boston University School of Medicine, 820 Harrison Ave., FGH Building, First Floor, Boston, MA 02118; email: naomi.ko@bmc.org.
Disclosures: The authors report no relevant financial disclosures.
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Christina Hunter Chapman, MD, MS
This important analysis by Ko and colleagues demonstrated that a substantial portion of racial/ethnic disparities among those diagnosed with higher-stage breast cancer are mediated through health insurance coverage. This study is timely, as conversations continue at the state and national level regarding strategies for improving the U.S. health insurance system. Addressing disparities in occurrence of higher stage at cancer diagnosis may seem beyond the purview of the oncology community; however, oncologists may be optimally poised to direct further research in this area and to help develop evidence-based policies to reduce disparities in insurance access and timeliness of care.
Health policy interventions can be challenging to study, as they rarely are enacted in a randomized fashion. In this study, confounding remains an important limitation, as uninsured and Medicaid patients are well-known to possess increased risk factors for presenting at an advanced stage. Many of the social demographic covariates were at the county vs. individual level, raising the possibility that individual or other unmeasured factors contributed to delayed presentation. Future studies that employ quasi-experimental techniques or true randomization may strengthen the level of evidence. Further, although it is well-known that there are critical flaws with studies that show Medicaid patients fare no better than the insured, this study does not answer the critically important policy question of whether receipt of Medicaid contributes to early stage at diagnosis compared with no insurance. However, there remains a strong rationale for the hypothesis that underinsurance may delay cancer diagnosis, and this study reaffirms the need for further research.
Initial breast cancer workup is expensive, and many patients are referred for routine screening by primary care, which may be inaccessible to those who are under- or uninsured. Other research, such as the study by Adamson and colleagues presented at last year’s ASCO Annual Meeting, suggest that Medicaid expansion may reduce racial disparities in cancer care timeliness.
Despite the study limitations, there are important findings to be noted. First, it remains striking that even in recent years, there are stark racial and sociodemographic disparities in insurance status, especially among those who need to undergo expensive cancer treatment. It is well-known that all insurances do not provide equal access, given that some practices decline Medicaid patients due to poor reimbursement or other issues. This is a major cause for concern, regardless of the impact of insurance status on stage at diagnosis. Further, persistent racial and sociodemographic disparities in stage at diagnosis are themselves concerning, and the findings again confirm that biology (via subtype) does not adequately account for this, suggesting that inequities in our health care system continue to play a large role. These inequities must be addressed to ensure oncologic advances reach all populations.
Reference:
Adamson BJS, et al. Abstract LBA1. Presented at: ASCO Annual Meeting; May 31-June 4, 2019; Chicago.
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