Asal Pilehvari, Qingyi He, Gretchen Kimmick, Roger Anderson
Among 7194 women (10.9% non-Hispanic [NH] Black, 15.3% dual-eligible), the frailty level was higher among NH Black patients than NH White patients (0.21 vs 0.15; p < 0.001) and among dual-eligible than non-dual-eligible patients (0.24 vs 0.15; p < 0.001). In RIF decomposition analysis, differences in frailty levels at the mean were explained by observed characteristics, while differences at the 75th percentile remained largely unexplained for both race (67%) and dual eligibility (74%). At the 90th percentile, the racial differences in frailty burden were fully explained, whereas among chemotherapy recipients, 54% of the differences by dual eligibility status remained unexplained.
INTRODUCTION: Frailty may influence treatment tolerance, supportive care needs, and quality of life among older women with metastatic breast cancer (MBC). However, racial and socioeconomic status (SES) disparities in frailty burden, and whether these disparities vary by frailty severity, have not been examined.
MATERIALS AND METHODS: Using Surveillance, Epidemiology, and End Results linked to Medicare administrative claims (SEER-Medicare) from 2010 to 2020, we identified women aged ≥66 diagnosed with de novo MBC. Frailty burden 6 months post-diagnosis was measured with the claims-based frailty index. Quantile regression at the 50th, 75th, and 90th percentiles assessed associations of race and Medicare-Medicaid dual eligibility with frailty severity, adjusting for clinical and contextual covariates and stratifying by chemotherapy receipt. The recentered influence function (RIF) Oaxaca-Blinder decomposition partitioned disparities into explained and unexplained components.
RESULTS: Among 7194 women (10.9% non-Hispanic [NH] Black, 15.3% dual-eligible), the frailty level was higher among NH Black patients than NH White patients (0.21 vs 0.15; p < 0.001) and among dual-eligible than non-dual-eligible patients (0.24 vs 0.15; p < 0.001). In RIF decomposition analysis, differences in frailty levels at the mean were explained by observed characteristics, while differences at the 75th percentile remained largely unexplained for both race (67%) and dual eligibility (74%). At the 90th percentile, the racial differences in frailty burden were fully explained, whereas among chemotherapy recipients, 54% of the differences by dual eligibility status remained unexplained.
DISCUSSION: Racial and SES differences in frailty burden varied across the levels of frailty severity. Examining disparities across frailty severity can identify where inequities are most pronounced and which subgroups may benefit from targeted intervention.