Total Body Irradiation and Risk of Diabetes Mellitus; A Meta-Analysis

OBJECTIVE: Hematopoietic stem cell transplant (HSCT) has recently emerged as a cure for previously “incurable” diseases and is being explored and attempted in many other fields including congenital and acquired non-malignant diseases. However, the long-term side effect associated with HSCT especially Total Body Irradiation (TBI) is still understudied. Therefore, we attempted to establish association between TBI and risk of developing Diabetes Mellitus (DM) or impaired glucose metabolism (IGM). METHODS: We searched for titles of articles in MEDLINE (PubMed), EMBASE, and Cochrane library in August 2018 that evaluated the association between TBI in the setting of HSCT and DM or IGM. We conducted a random effect meta-analysis of 11 studies involving a total of 13,191 participants and reported the pooled MD (mean difference) for the development of DM/IGM after TBI as part of the conditioning regimen for HSCT. RESULTS: We found a significant increase in the risk of developing DM/IGM after TBI is used as part of the conditioning regimen compared to other types of conditioning regimen with the pooled MD being 5.42, 95% Confidence Interval (CI) 2.51-11.71, I2=92.4%. CONCLUSION: TBI as a conditioning regimen in the setting of HSCT significantly increases the risk of developing DM/IGM. Therefore, we recommend close monitoring and screening for diabetes mellitus in patients who underwent TBI before HSCT.