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General Endocrinology

MON-858 - Association between serum vitamin D levels and disease activity (SLEDAI) in systemic lupus erythematosus: a systematic review

Monday, June 15, 2026
9:00 AM - 2:00 PM CT


Introduction: Systemic lupus erythematosus (SLE) is a chronic, autoimmune, multisystem disease characterized by periods of activity and remission. SLEDAI is a validated tool for assessing disease activity over the past 30 days based on 24 clinical and laboratory parameters. Vitamin D is a steroid hormone with immunomodulatory properties, acting in immune modulation and inflammation reduction. Its deficiency is common in SLE patients due to photosensitivity, with an estimated prevalence of 70–90%. Observational studies suggest an association between vitamin D levels and disease activity; however, results remain conflicting. Thus, there is a need to systematically evaluate this association using SLEDAI.

Objective: To evaluate the association between serum vitamin D levels and disease activity, measured by SLEDAI, in patients with SLE.

Methods: Systematic review with meta-analysis following PRISMA guidelines. Search in PubMed, Cochrane Library, and Embase (up to December 2024) identified 249 studies, with 36 selected for qualitative synthesis after double-blind screening using Rayyan. Adults with SLE were included, stratified by vitamin D levels or correlation analysis, evaluating: SLEDAI/SLEDAI-2K scores; association between vitamin D and SLE activity; and exacerbations. Meta-analysis was performed using a random-effects model with 95% CI and heterogeneity assessed by I².

Results: Most studies demonstrated an inverse relationship between vitamin D levels and SLE activity. Deficiency was associated with higher frequency of exacerbations, elevated inflammatory markers, pro-inflammatory cytokines, autoantibodies, fatigue, cardiovascular risk, greater organ involvement, and poorer quality of life. Higher vitamin D levels were associated with reduced disease activity and fewer flares. However, some studies found no significant association regardless of the index used. In the meta-analysis (7 studies; n=985), a moderate negative correlation was observed (r=-0.382; 95% CI: -0.577 to -0.145; p=0.009; Fisher's z=-0.402). Heterogeneity was high (I²=88.25%), reflecting variability related to vitamin D cutoffs, supplementation use, population characteristics, and disease activity assessment methods.

Conclusion: A significant inverse association between vitamin D levels and SLE activity measured by SLEDAI was observed, suggesting that lower levels are associated with higher disease activity. However, high heterogeneity and methodological variations limit causal inference. Findings reinforce the potential of vitamin D as a complementary biomarker of disease activity and possible adjuvant therapeutic target. Randomized controlled trials are warranted to establish causality and determine its true clinical impact.

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