Health insurance literacy, status, and financial toxicity in women receiving treatment for metastatic breast cancer

96 Background: Though uninsurance rates declined after the Affordable Care Act, the number of underinsured, or individuals who spend > 10% of their income on out-of-pocket (OOP) medical costs, continues to rise. In patients with metastatic breast cancer (MBC), underinsurance may lead to financial toxicity (FT), or patient-level financial burden and distress, since diagnosis and treatment is extremely costly. This study explores health insurance literacy and the association between FT and health insurance status in women receiving treatment for MBC. Methods: This cross-sectional study utilized survey data collected from 2017-2019 in women age ≥18 receiving treatment for MBC at two academic medical centers in Alabama. FT was measured by the Comprehensive Score for Financial Toxicity (COST) tool (11-item scale from 0-44, with lower scores indicating worse FT). Health insurance status and OOP costs were self-reported. Effect sizes were calculated using Cohen’s d or Cramer’s V. Mixed and generalized linear models clustered by site and treating medical oncologist estimated the association between FT and health insurance status. Results: In 81 women with MBC, median COST score was 24 (interquartile range [IQR] 17-30), 44% had private insurance, 40% Medicare, and 16% Medicaid. Though 25% and 33% of surveyed patients did not know their health insurance premium or deductible cost, respectively, privately insured patients more often knew the cost of their premiums (97%; V = 0.58) and deductibles (81%; V = 0.33) compared to publicly insured patients. In adjusted models, FT levels did not differ significantly based on health insurance type (private insurance COST 21, 95% confidence interval [CI] 18-25; Medicaid COST 23, 95% CI 17-29; Medicare COST 24, 95% CI 20-27). However, risk of severe FT (COST ≤13) was 147% higher for privately insured patients versus Medicare beneficiaries (risk ratio 2.47, 95% CI 1.44-4.21). Conclusions: Despite higher levels of health insurance literacy, privately insured patients receiving treatment for MBC may be at increased risk of severe FT. Further research is needed to understand causes of underinsurance in patients with MBC, which could lead to cancer-related FT.