Introduction: Sociodemographic factors influence all aspects of the allogeneic hematopoietic cell transplantation (HCT) process. Their impact on conditioning intensity selection is under-explored. Myeloablative conditioning (MAC) decreases the risk of relapse but carries an increased risk for non-relapse mortality. We investigated if sociodemographic factors influenced the perception of tolerance of different conditioning intensities.

Methods: We used a publicly available dataset (IB20-03) from the Center for International Bone Marrow Treatment and Research (CIBMTR) supported by the Public Health Service U24CA076518 from the NCI; the NHLBI; the NIAID; 75R60222C00011 from the Health Resources and Services Administration; N00014-23-1-2057 and N00014-24-1-2057 from the Office of Naval Research; NMDP; and the Medical College of Wisconsin. We included patients diagnosed with acute myeloid leukemia (AML), chronic myeloid leukemia (CML) or myelodysplastic syndrome (MDS) from 2000-2013 across 125 transplant centers in the United States.

Conditioning intensity was categorized as myeloablative (MAC) and non-myeloablative (NMA)/reduced intensity conditioning (RIC). Sociodemographic and clinical factors included age, sex, income, education, employment, residence rurality, housing, HCT comorbidity index (CI), a socioeconomic status (SES) composite score (income, % below poverty level, education, housing, unemployment) and Karnofsky Performance Status (KPS). The odds of receiving MAC vs NMA/RIC were examined using Kruskal-Wallis, Chi-Square, and multivariable logistic regression. Survival was assessed using the Kaplan-Meier method with a log-rank test.

Results: A total of 1675 patients with myeloid malignancies were included. Their median age was 52 (IQR 40-61), 54.9% were male, and 94% identified as White. There were 65.4% transplanted for AML and 34.6% for MDS/CML. Additionally, 61.3% (n=1026) received MAC and 38.7% (n=649) NMA/RIC.

Of those who received MAC(n=1026), 67.7% had AML, and 32.3% had MDS/CML. The median age of the MAC population was 46 (IQR 34-54), 52.9% were male, 93.3% identified as White, 58.1% had an HCT-CI score of 0-2, and 66.2% had a KPS score of >=90. 84.6% lived in census blocks considered non-rural (urban). The majority (62.8%) had CPI-adjusted median household income in the $50,000-100,000 range. The median % of population >= 25 without a high school education was 11.7%. Additionally, 24.4% of the population had the most advantaged SES while 23.7% had the most disadvantaged SES.

There were 649 pts who received NMA/RIC, and of this 61.6% had AML and 38.4% MDS/CML. The median age was 60 (IQR 55-65), 57.9% were male, 95.1% identified as White, 50.4% had an HCT-CI score of 0-2, and KPS was >= 90 in 58.9%. 82.7% lived in non-rural (urban) census blocks. There were 62.1% of pts with CPI-adjusted income that ranged from $50,000-100,000. Median % of the population >=25 without a high school diploma was 11.1%. There were 26.7% with the most advantaged SES and 21.7% with the most disadvantaged SES.

Compared to NMA/RIC group, the MAC group included pts who were younger, male, had fewer comorbidities and better KPS. In our adjusted model, increasing age was associated with lower odds of MAC ([Odds ratio (OR) 0.88], {95% CI 0.86-0.90}, p <0.01), advanced disease with higher odds ([OR 1.75],{1.16-2.66}, p= 0.02) and KPS <90 with lower odds ([OR 0.68], {0.46-0.99}, p=0.05). There was a trend towards higher odds of MAC with an AML diagnosis ([OR 1.33] {0.88-2.01}, p= 0.18). There were trends related to sex, income and HCT-CI but these were not statistically significant covariates.

There was a higher probability of progression free survival (PFS; p=0.0020), disease free survival (DFS; p= 0.0009) and overall survival (OS; p= 0.0103) for MAC in comparison to NMA/RIC. There was no statistically significant difference in PFS, DFS, and OS for rural residence, race, sex, income, and SES score.

Conclusions: In this publicly available multi-center dataset, age was the only significant sociodemographic variable for the choice of conditioning intensity for allogeneic HCT for myeloid malignancies. Additionally, these sociodemographic factors did not affect survival in this particular dataset. It is reassuring that conditioning intensity selection appears to be guided by clinical factors rather than sociodemographic characteristics, supporting our collective efforts to offer the best possible treatment to all transplant recipients.

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2025
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