Impact of Socioeconomic Status on Utilisation of ASCT and Overall Survival in Multiple Myeloma: A Report from the Australian and New Zealand (ANZ) Myeloma and Related Diseases Registry (ANZ MRDR)

Aim: There has been a dramatic improvement in survival outcomes in multiple myeloma (MM) over the last 20 years. However, these benefits have not been recognised equally among patient populations1. We aimed to assess the impact of non-biologic factors on treatment and survival outcomes. Method: We conducted a retrospective review of 3392 MRDR patients with MM from 44 sites across Australian and New Zealand between June 2012-April 2024. Tertiles of area-level socioeconomic status (SES) were generated by linking individual postcodes to data from the Australian Bureau of Statistics utilising the composite Index of Relative Socio-economic Advantage and Disadvantage (IRSAD) score. Baseline characteristics and therapeutic management options were compared between high (n=1115), medium (n=1123) and low (n=1138) SES tertiles as well as between ASCT recipients and non-recipients. Kaplan-Meier methods were used to estimate progression free survival (PFS) and overall survival from the date of diagnosis (OS). Multivariate analysis was undertaken for PFS and OS using Cox regression. Results: Lower SES (low vs middle vs high) correlated with higher median BMI (28.34 vs 27.44 vs 26.13, p<0.001), increased rates of diabetes (14.91% vs 12.38% vs 8.69%, p<0.001), pulmonary disease (7.31% vs 4.99% vs 3.34%, p<0.001%) and ECOG≥2 (19.80% vs 17.16% vs 14.84%, p=0.044). Median age at diagnosis differed between low, middle and high SES groups but was not correlated with higher SES (68.3 vs 66.9 vs 68.3 years). There was no statistical difference between SES groups for gender, ethnicity, disease stage (ISS-3), liver disease or peripheral neuropathy. Clinical trial inclusion and which chemotherapy regime utilised at first or second line were similar amongst SES groups. However, likelihood of ASCT significantly increased with higher SES (low = 46.8% vs middle = 54.1% vs high = 56.3%) (odds ratio = 1.34 middle vs low, p=0.003 and 1.47 high vs low, p<0.001). After adjustment for age, pulmonary disease, diabetes and ECOG, statistical significance persisted between low and high SES (odds ratio 1.71, p<0.001). There was a trend towards better PFS with higher SES (low = 30.6 vs middle = 32.6 vs high = 35.4 months, p=0.084). OS significantly improved for the middle and high relative to low SES tertile (median low = 73.4 vs middle= 94.8 and high = 86.1 months) (hazard ratio = 0.76 middle vs low, p=0.001 and 0.8 high vs low, p=0.005). These findings retained statistical significance after adjustment for age at diagnosis, BMI, diabetes, pulmonary disease and ECOG (hazard ratio = 0.76 middle vs low, p=0.001 and 0.8 high vs low, p=0.025). Conclusion: These data demonstrate a significant disparity in OS and utilisation of ASCT, favouring higher SES independent of biological factors, in a universal healthcare model. Given ASCT has proven survival benefit2 and is recommended as upfront treatment for eligible patients3, this disparity warrants further research to address barriers and enhance equitable outcomes. References: 1. Miranda-Galvis M et al. Disparities in survival of hematologic malignancies in the context of social determinants of health: a systematic review. Blood Adv. 2023 14;7:6466-91 2. Richardson PG et al. Triplet Therapy, Transplantation, and Maintenance until Progression in Myeloma. NEJM2022;387:132-147 3. Dimopoulos MA et al. Multiple myeloma: EHA-ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2021;32:309-22.