Impact of socioeconomic status on treatment and survival in multiple myeloma in Australia

<title>Abstract</title> Outcomes in multiple myeloma (MM) have improved significantly but remain heterogeneous. We assessed the impact of non-biological social determinants of health on treatment and survival outcomes in Australia using data from the Australian and New Zealand Myeloma and Related Diseases Registry. A total of 4405 patients diagnosed with MM between June 2012 and October 2025 across 44 Australian sites were assigned an area-level socioeconomic status (SES) using individual postcodes. Baseline characteristics, treatment and survival outcomes were compared across high (n=1484), medium (n=1463), and low (n=1458) SES tertiles. Lower neighbourhood SES was associated with higher BMI, poorer functional status, more comorbidities (diabetes, cardiac and pulmonary disease), Asian ethnicity and greater remoteness. Independent of these baseline differences, patients from lower SES neighbourhoods were less likely to receive an autologous stem cell transplant (odds ratio = 1.1 medium vs low, p=0.41; 1.5 high vs low, p&lt;0.01) and time to reach ASCT following induction was longer (p&lt;0.001) despite this being standard-of-care therapy with proven survival benefit. Median overall survival was shorter for the low SES group at 78.5 months compared to 92.5 months (HR=0.85, p=0.01) and 86.7 months (HR=0.85, p=0.01) for the medium and high SES groups respectively. These findings demonstrate significant disparities in treatment and outcomes favouring higher SES, independent of biological factors, within a universal healthcare system. This suggests that non-biological factors continue to influence access to standard-of-care therapy and survival, warranting further research to identify and address barriers to equitable care.