Association Between Socioeconomic Inequalities and Health-Related Quality of Life in Patients With Relapsed/Refractory Multiple Myeloma

PURPOSE: Owing to prolonged treatment exposure, patients with relapsed/refractory multiple myeloma (RRMM), particularly those with low socioeconomic status (SES), may be especially vulnerable to financial toxicity (FT), which can negatively affect their health-related quality of life (HRQoL). We aimed to evaluate the association between SES and HRQoL in patients with RRMM and to explore the mediating role of FT in this relationship. METHODS: We conducted a cross-sectional analysis of baseline data from a multicenter, prospective, observational study of patients with RRMM in Italy and the United Kingdom. SES was assessed via a composite index including education, employment, and living arrangements. We evaluated HRQoL using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) and QLQ-MY20. Multivariable regression models adjusted for potential confounders were used to assess the association between SES and HRQoL. Mediation analysis was conducted to examine the role of FT in the relationship between SES and HRQoL. RESULTS: A total of 505 patients with RRMM were analyzed, and 15.6%, 49.3%, and 35.1% were classified as low, middle, and high SES, respectively. Patients with low versus high SES reported clinically meaningful worse scores in 11 EORTC QLQ-C30 scales and in the QLQ-MY20 disease symptoms scale. Compared with patients with high SES, those with low SES had significantly higher odds of reporting clinically important pain (odds ratio [OR], 3.55), financial difficulties (OR, 2.97), and impaired physical functioning (OR, 2.96). FT significantly and partially mediated the relationship between SES and HRQoL, accounting for 46.3% of the total effect. CONCLUSION: Patients with RRMM and low SES experienced worse HRQoL compared with those with higher SES, with FT partially mediating this association. Interventions addressing FT and broader social determinants of health in RRMM are warranted to reduce disparities and promote equity in cancer outcomes.