Vitamin D deficiency is not associated with graft versus host disease after hematopoietic stem cell transplantation: A meta-analysis.

OBJECTIVE Vitamin D status plays an important role in immunoregulation, and a deficiency is believed to be related to Graft Versus Host Disease (GVHD) in patients after hematopoietic stem cell transplantation (HSCT). We aim to study the association between vitamin D deficiency and GVHD after HSCT. METHODS A literature search was conducted utilizing MEDLINE, EMBASE, and The Cochrane Library Database from inception to July 2019. Eligible studies were required to be clinical trials or observational studies (cohort, case-control, or cross-sectional studies); provide data to calculate the odds ratios (OR) of GVHD in HSCT patients with vitamin D deficiency. Two reviewers independently extracted the data and assessed the risk of bias. Pooled odds ratios (OR) with 95% confidence interval (CI) were estimated using random-effects meta-analysis through the Comprehensive Meta-Analysis 3.3 software. RESULTS In total, 8 observational studies consisting of 1335 HSCT patients were enrolled in this systematic review. Overall, there was no significant association between vitamin D deficiency and acute GVHD (OR = 1.06, 95% CI 0.74-1.53, P > 0.05). There was no significant association between vitamin D deficiency and chronic GVHD (OR = 1.75, 95% CI 0.72-4.26, P > 0.05). Funnel plots and Egger regression asymmetry test were performed and showed no publication bias. CONCLUSION There is not a statistically significant association between vitamin D deficiency and neither acute nor chronic GVHD