Vitamin D Levels in Patients with Behcet's Disease: A Systematic Review and Meta-Analysis

Objective: Behcet’s disease (BD) is a chronic multisystem inflammatory disease classified as Variable Vessel Vasculitis with unclear etiology. We designed this systematic review and meta-analysis to evaluate vitamin D status in Behcet’s disease patients with this background. Methods: We performed this systematic review and meta-analysis according to PRISMA guidelines. We included all observational studies in humans published in English, evaluating the association of 25(OH)D concentrations in Behcet’s patients. Two reviewers (HRK and AE) independently searched the databases and screened articles based on their titles and abstracts. A third reviewer resolved all disagreements. We performed analysis using Cochrane Program Review Manager Version 5.3. The protocol for this review was registered on PROSPERO (CRD42020197426). Results: A total of 341 publications were initially identified according to the search strategy. Finally, 12 publications were included in the meta-analysis. We performed this meta-analysis on 1265 participants from different studies with a sample size ranging from 63 to 224 individuals. In studies comparing active and inactive subgroups of patients with Behcet’s disease, we found a significantly lower serum level of vitamin D in patients with Active BD (-0.4; 95% CI: -0.61, -0.25; p<0.001). We found that the serum level of vitamin D in Behcet’s disease is significantly higher than in health controls (0.5; 95% CI: 0.15, 0.50; p=0.001). Conclusion: We demonstrated that the existing evidence is consistent with the hypothesis that an increased serum level of vitamin D would be associated with a substantially lower risk of active Behcet’s disease.