Impact of Pre-Transplant Diabetes and Obesity on Outcomes After Allogeneic HCT

Overview

This large EBMT registry study evaluated the influence of pre-transplant diabetes and obesity on acute graft-versus-host disease (GvHD), relapse, and mortality in adult patients undergoing allogeneic hematopoietic cell transplantation (HCT). The study found no significant increase in the incidence of grade II–IV acute GvHD associated with pre-transplant diabetes or obesity but noted important implications for non-relapse mortality and overall survival.

Background

Obesity and diabetes induce metabolic and inflammatory changes that may affect immune responses post-transplant. Preclinical models suggest obesity exacerbates acute GvHD severity, potentially via pro-inflammatory cytokines and gut microbiome alterations. Clinical data on the impact of pre-transplant diabetes and obesity on acute GvHD and transplant outcomes have been inconsistent, with prior studies limited by sample size and transplant era. The EBMT study aimed to clarify these associations in a contemporary cohort.

Data Highlights

Key Findings

• Pre-transplant diabetes, defined as requiring pharmacologic treatment, was present in 4.4% of patients undergoing allogeneic HCT between 2016 and 2020.
• Pre-transplant obesity (BMI ≥30 kg/m2) was present in 3.9% of patients in the same cohort.
• Neither pre-transplant diabetes nor obesity was significantly associated with an increased incidence of grade II–IV acute GvHD after multivariable adjustment.
• Previous studies have shown conflicting results regarding the impact of obesity and diabetes on acute GvHD, but a consistent association exists between obesity and increased non-relapse mortality.
• The study adjusted for multiple confounders including donor type, conditioning intensity, and disease risk, enhancing the robustness of findings.
• Given the increasing prevalence of diabetes and obesity, understanding their impact on transplant outcomes remains clinically important.

Clinical Implications

Clinicians can counsel patients with pre-existing diabetes or obesity that these conditions do not appear to increase the risk of developing moderate to severe acute GvHD after allogeneic HCT. However, attention should be paid to the potential impact of obesity on non-relapse mortality and overall survival. Careful management of metabolic comorbidities remains essential to optimize transplant outcomes.

Conclusion

In this contemporary EBMT cohort, pre-transplant diabetes and obesity were not associated with a higher incidence of grade II–IV acute GvHD, though obesity’s impact on non-relapse mortality warrants further attention. These findings provide valuable prognostic information for patients with metabolic comorbidities undergoing allogeneic HCT.

References

1. EBMT Transplant Complications Working Party -- Influence of Pre-Transplant Diabetes and Obesity on Acute GvHD and Outcomes