|The following article features coverage from the American Society of Hematology 2021 meeting. Click here to read more of Hematology Advisor‘s conference coverage.|
Substantial disparities by race/ethnicity and socioeconomic status were observed in survival outcomes of children with acute lymphoblastic leukemia (ALL), according to research presented at the 2021 American Society of Hematology (ASH) Annual Meeting.
“We are all increasingly aware that health disparities are major issues for racial, ethnic, and socioeconomically disadvantaged groups,” said Sumit Gupta, MD, of the University of Toronto and The Hospital for Sick Children in Toronto, Canada, who presented the findings.
Although outcomes in children with ALL have steadily been improving, persistent disparities appear to remain. To evaluate potential differences in persistent inequities by race/ethnicity and socioeconomic status in childhood ALL, Dr Gupta and colleagues studied outcomes of all patients enrolled in Children’s Oncology Group (COG) frontline ALL trials over a 15-year period, assembling largest cohort ever assembled for this purpose, according to the researchers.
The cohort included patients with newly-diagnosed ALL, aged 0-31 years, who were enrolled on COG trials between 2004-2019. Patients’ race/ethnicity was categorized as non-Hispanic White, Hispanic, non-Hispanic Black, non-Hispanic Asian, and non-Hispanic other. Insurance status was used as a proxy for socioeconomic status: United States Medicaid, which provides public health insurance for low-income individuals; US other, which was predominantly private insurance; and non-US-based coverage, which was predominantly universal health insurance from other jurisdictions.
The team compared event-free survival (EFS) and overall survival (OS) rates across race/ethnicity and socioeconomic status, including the relative contribution of disease prognosticators (age, sex, white blood cell count, lineage, central nervous system status, cytogenetics, and induction minimal residual disease) with multivariable models.
Overall, 24,979 children, adolescents, and young adults with ALL were included in the study. The cohort was 65.6% non-Hispanic White, 20.6% Hispanic, 7.2% non-Hispanic Black, 5.1% non-Hispanic Asian, and 1.6% non-Hispanic other. Insurance among the cohort was 27.8% US Medicaid, 59.9% US other, and 12.6% non-US-based coverage.
Non-Hispanic White patients had higher 5-year EFS rate when compared with Hispanic patients (87.4% vs 82.8%; hazard ratio [HR], 1.37; 95% CI, 1.26-1.49; P <.0001) and with non-Hispanic Black patients (87.4% vs 81.9%; HR, 1.45; 95% CI, 1.28-1.56; P <.0001). No significant differences in outcomes were observed between non-Hispanic Asian patients and non-Hispanic White patients.
Patients on US Medicaid had lower 5-year EFS rate than patients on US-other insurance (83.2% vs 86.3%; HR, 1.21; 95% CI, 1.12-1.30; P <.0001). Patients on non-US-based coverage demonstrated the best outcomes among the groups, with higher 5-years EFS rate than patients on US-other insurance (89.0% vs 86.3%; HR, 0.78; 95% CI, 0.71-0.88; P <.0001). Similar results were observed for 5-year OS.
Significant differences were observed in traditional disease prognosticators across both race/ethnicity and socioeconomic status and of race/ethnicity by socioeconomic status. For example, patients with T-lineage ALL were 17.6% non-Hispanic Black, 9.4%, non-Hispanic White, and 6.6% Hispanic (P <.0001).
The researchers found that the inferior EFS among Hispanic children relative to non-Hispanic White children was attenuated (HR decreased from 1.37 to 1.17) when disease prognosticators were added to the models and further attenuated by subsequent addition of socioeconomic status (HR decreased to 1.11). They observed that the increased risk among non-Hispanic Black children relative to non-Hispanic White children was minimally attenuated when with addition of disease prognosticators and subsequent addition of socioeconomic status to the models (HR decreased from 1.45 to 1.38 and then to 1.32).
With the addition of race/ethnicity and disease prognosticators to the models, the researchers also saw attenuation of the superior EFS in patients on non-US-based coverage relative to patients on US-other insurance (HR decreased increased 0.78 to 0.94) and minimal attenuation of the increased risk among patients on US Medicaid relative to those on US-other insurance (HR decreased from 1.21 to 1.16). Similar patterns were observed for disparities in OS, but the differences were consistently worse than those in EFS.
Limitations of the study included self-reported race/ethnicity, change-in-estimate methodology, and that all patients were treated on clinical trials.
“In conclusion, substantial disparities by race, ethnicity and socioeconomic status exist and are not fully attributable to differences in leukemia biology or disease prognosticators. It is crucial that the mechanisms underlying these disparities be elucidated and interventions be designed and evaluated,” said Dr Gupta.
Disclosure: Some study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Read more of Hematology Advisor‘s coverage of the ASH 2021 meeting by visiting the conference page.
Gupta S, Teachey D, Devidas M, et al. Racial, ethnic, and socioeconomic factors result in disparities in outcome among children with acute lymphoblastic leukemia not fully attenuated by disease prognosticators: a children’s oncology group (COG) study. Presented at ASH 2021; December 11-14, 2021. Abstract 211.