Background Recently, it was suggested that vitamin D plays an important role in immunoregulation as well as bone metabolism. Previous studies showed that vitamin D level was associated with disease activity in patients with systemic lupus erythematosus (SLE), representing autoimmune disease. However, a little is known about the effect of low vitamin D level on lupus flare, in lupus nephritis patients particularly.
Objectives The aim of this study is to investigate the role of low vitamin D levels in predicting lupus nephritis flare.
Methods Serum 25(OH)D levels were measured in 202 patients with SLE visited rheumatologic clinic of Asan Medical Center between May 2013 and July 2013. We followed up these patients for more than 1 year and assess the lupus nephritis (LN) flare in nephritis patients. LN flare was defined as ≥1000mg albumin/creatinine ratio, ≥5 RBCs/HPF in the spot urine and change of immunosuppressant medication. Predictive factors of LN flare were identified by the binary logistic regression analysis.
Results The mean 25(OH)D level of 202 patients with SLE was 18.44 (19.48 ng/mL in general population according to Korean Nationwide Surveys) and mean SLEDAI score was 4.46±3.80. 77 (38.1%) patients had LN and LN flare occurs in 27 (13.8%) patients. In univariate analysis, age, 25(OH)D, Anti-SM antibody, C3, HCQ were associated with the LN flare (p<0.2) and were then included in the multivariate analysis. Of these, only low 25(OH)D (p=0.008) and C3 (P=0.034) levels were predictors of LN flares in multivariate analysis.
Conclusions Our finding suggested that level of vitamin D could be a marker for prediction of LN flare.
Disclosure of Interest None declared