Purpose: Racial minority cancer patients may experience underuse of antiemetic medications to prevent chemotherapy-induced nausea and vomiting (CINV). In addition to its adverse implications for quality of life, antiemetic underuse may contribute to observed disparities in acute illness during chemotherapy. To understand the potential contribution of CINV prophylaxis to breast cancer disparities, we assessed racial variation in potent antiemetic use and post-chemotherapy utilization related to CINV and the relationship between the two.
Methods: We used SEER-Medicare data to evaluate the health care utilization in the 14 days following chemotherapy initiation among black and white women receiving highly emetogenic chemotherapy for breast cancer. We used modified Poisson regression to assess the relationship between (1) race and CINV-related utilization and (2) NK1 use and CINV-related utilization, overall and stratified by race. We report adjusted risk ratios (aRR) and 95 % confidence intervals (CI).
Results: The study included 1130 women. Black women were 11 % less likely than white women to use neurokinin-1 receptor antagonists (NK1s) for CINV prophylaxis (p = 0.02); however, they experienced fewer CINV-related encounters following chemotherapy (unadjusted RR = 0.63, 95 %CI = 0.40-0.99; p = 0.05). After adjustment for clinical covariates, estimates were similar but no longer statistically significant (p = 0.07). Among white women, NK1 use was associated with increased CINV-related utilization (aRR NK1 users vs. non-users: 1.35, 95 % CI = 1.07-1.69, p = 0.01), likely resulting from unmeasured confounders.
Conclusion: Black women were less likely to use NK1s- and CINV-related services. Racial variation in CINV-related services use may be partly explained by differential symptom reporting or access to care.
Keywords: Breast cancer; Neurokinin-1 receptor antagonists; Quality of life.