Association between Vitamin D Deficiency and Disease Activity in Systemic Lupus Erythematosus (SLE).

Abstract

Objective: To evaluate the association between SLE patients' disease activity and blood 25-hydroxyvitamin D [25(OH)D] levels. Study Design: Cross-sectional Analytical Investigation. Setting: Bahawal Victoria Hospital, Bahawalpur. Period: January and December 2025. Methods: A total of 85 adult SLE patients who met the 2019 EULAR/ACR criteria participated SLEDAI-2K, BILAG-2004, PGA, and serological markers were used to evaluate disease activity. Vitamin D status was categorized per standard thresholds. Spearman’s correlation and multivariable linear and logistic regression models were used, adjusting for age, gender, BMI, prednisolone dose, hydroxychloroquine use and sun avoidance. Results: Vitamin D deficiency (<20 ng/mL) was present in 63.5% of patients. Significant inverse correlation was observed between 25(OH)D and SLEDAI-2K (ρ = –0.34, p = 0.001). Each 10 mg/mL increase in 25(OH)D was linked with a 1.8-point reduction in SLEDAI-2K (p = 0.002). Deficient patients had 3.7-fold higher odds of high disease activity (adjusted OR = 3.72, p = 0.025). Conclusion: Deficiency of Vitamin D is common and independently linked with higher disease activity in Pakistani SLE patients, supporting routine screening and repletion.