Background: The aim of this study was to check the effectiveness of Vitamin D supplementation on the disease activity of Vitamin D-deficient systemic lupus erythematosus (SLE) patients.
Materials and methods: In this randomized, double-blind, placebo-controlled trial, 45 Vitamin D-deficient SLE patients were studied in two groups, namely interventional and placebo groups. The interventional group patients were treated with Vitamin D (50,000 unit/weekly Vitamin D for 12 weeks and then 50,000 unit/monthly for 3 months) and placebo group patients were only administered the placebo. The level of Vitamin D and the level of disease activity using SLE disease activity index (SLEDAI) were measured before and after intervention period in each group, and for intra- and between-groups comparison, we used t-test and repeated measure ANOVA.
Results: A total of 90 patients were enrolled in this study. The mean of Vitamin D was increased significantly after therapy in interventional group (17.36 ± 4.26 ng/ml vs. 37.69 ± 5.92 ng/ml, P < 0.001). The mean of Vitamin D had no significant difference before and after intervention in placebo group (16.78 ± 4.39 ng/ml vs. 16.62 ± 4.61 ng/ml, P = 0.53). The mean of disease activity (SLEDAI) was not different significantly before and after Vitamin D administration in interventional group (3.09 vs. 1.62 ± 1.25, P = 0.39). The mean of disease activity (SLEDAI) was not different significantly before and after intervention in placebo group (3.09 vs. 1.98 ± 2.47, P = 0.42).
Conclusion: According to our study, it is suggested that using Vitamin D in patients with SLE could not have better outcomes in this regard. However, there are many unknown environmental or biological factors which are associated with the disease activity of SLE and have not been identified yet.
Keywords: Disease activity; Vitamin D; systemic lupus erythematosus.