Vitamin D status in patients with systemic lupus erythematosus (SLE): A systematic review and meta-analysis

Abstract Background Systemic lupus erythematosus (SLE) is a systemic autoimmune disease where chronic inflammation and tissue or organ damage is observed. Due to various suspected causes, inadequate levels of vitamin D (a steroid hormone with immunomodulatory effects) has been reported in patients with SLE, however, contradictory. Aims The aim of this systematic review and meta-analysis was to evaluate the serum levels of vitamin D in patients with SLE in compared to healthy controls. Methods PubMed, SCOPUS, ScienceDirect and Google Scholar electronic databases were searched systematically without restricting the languages and year (up to March 2, 2019) and studies were selected based on the inclusion criteria. Mean difference (MD) along with 95% confidence intervals (CI) were used and the analyses were carried out by using a random-effects model. Different subgroup and sensitivity analyses were conducted. Study quality was assessed by the modified Newcastle-Ottawa Scale (NOS) and publication bias was evaluated by a contour-enhanced funnel plot, Begg's and Egger's tests. Results We included 34 case-control studies (2265 SLE patients and 1846 healthy controls) based on the inclusion criteria. Serum levels of vitamin D was detected significantly lower in the SLE patients than that in the healthy controls (MD: −10.44, 95% CI: −13.85 to −7.03; p  Conclusion Inadequate levels of serum vitamin D is significantly high in patients with SLE compared to healthy subjects, therefore, vitamin D supplementation with regular monitoring should be considered as part of their health management plans.