Association of Social Determinants of Health Status (SDOH) and Ethnicity with Survival in Multiple Myeloma Patients

Background

Despite the introduction of novel anti-myeloma therapies, Black patients with multiple myeloma (MM) often experience worse survival outcomes compared to their non-Hispanic White counterparts. In addition to disease-related factors, research has shown that cancer survival can be affected by non-clinical factors, such as insurance coverage, access to care, transportation hurdles, and socioeconomic status. This study evaluates the impact of a measure of neighborhood-level SDOH on survival outcomes in a MM patient population receiving comprehensive, guideline-concordant care inclusive of innovative treatment approaches. We hypothesized that higher Area Deprivation Index (ADI), indicating greater disadvantage, is associated with worse survival, and that this impact is greater among racial/ethnic minorities.

Methods

This retrospective cohort study included newly diagnosed MM patients seen at MD Anderson Cancer Center from 01/2010 to 12/2017. Data on demographics, disease features (e.g. heavy and/or light chain subtype, Revised-International Staging System (R-ISS) stage, cytogenetic risk, bone marrow plasma cell percentage at diagnosis), treatment, and follow-up were extracted from medical records. ADI was assessed from patients' residential ZIP codes at presentation to MD Anderson. Patients were categorized by ADI quartiles and into high/low ADI groups, defined as the top and lowest 25 percentile. Primary outcomes were progression-free survival (PFS) and overall survival (OS). Categorical characteristics and continuous variables were compared across race/ethnicities and ADI using t-tests or ANOVA. Kaplan-Meier methods and log-rank tests assessed subgroup differences in survival.

Results

The study included 476 MM patients with a median age of 60.9 years (IQR: 54.1-68.8). The cohort was 53.8% male, with 54.6% of patients self-identifying as White, 27.1% Black, and 18.3% Hispanic. Black and Hispanic patients were significantly younger at diagnosis compared to White patients, with a median age of 58.3 years (IQR: 51.2-66.8) for Black patients, 58.3 years (IQR: 51.5-65.8) for Hispanic patients, and 63.1 years (IQR: 56.2-70.0) for White patients. No significant differences were found in disease stage at diagnosis, though Black patients showed a trend towards fewer high-risk cytogenetics. There were no differences in PFS (p = 0.74) and OS (p = 0.66) durations by race/ethnicity.

White patients resided in neighborhoods with lower ADI (51.7 ± 23.3) representing lower deprivation compared to Black (61.2 ± 21.5) and Hispanic (63.7 ± 19.3) patients. Higher ADI correlated with advanced R-ISS stage 2-3, but not with other disease characteristics. No significant differences in PFS or OS were observed across ADI quartiles or by median ADI. Furthermore, PFS did not significantly differ between high and low ADI groups within racial/ethnic subgroups (Black: HR 0.91, CI 0.54-1.53, p=0.71; Hispanic: HR 0.71, CI 0.39-1.32, p=0.28; White: HR 0.69, CI 0.69-1.46, p=0.98). There were similarly no differences in OS by ADI within racial/ethnic subgroups. We further stratified the patient population by disease characteristics (stage and high-risk fluorescence in situ hybridization (FISH)) and treatment regimen to investigate the potential impact of ADI within these subgroups and showed no association with PFS or OS.

Conclusion

Overall, our analysis found no statistically significant differences in PFS or OS by ADI. Despite Black and Hispanic patients residing in neighborhoods with worse ADI, representing greater deprivation, survival outcomes were comparable across all groups. These findings require replication in other health care settings. However, the findings suggest access to multi-disciplinary, evidence-based care can attenuate potential disparities in outcomes created by SDOH factors.