Vitamin D Deficiency in Patients with Systemic Lupus Erythematosus – Prevalence and Clinical Associations

Background: Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by multisystem involvement and significant morbidity. Vitamin D, known for its immunomodulatory properties, has been increasingly linked to disease activity and clinical outcomes in autoimmune conditions, including SLE. Despite abundant sunlight in Bangladesh Objectives: This study aimed to determine the prevalence of vitamin D deficiency in Bangladeshi patients with SLE and to explore its association with disease activity and organ involvement. Methods & Naterial: This cross-sectional study was conducted over one year at Dhaka Medical College Hospital and included 130 adult patients diagnosed with SLE according to the ACR 1997 criteria. Participants were categorized based on serum 25(OH)D levels into three groups: deficient (<20 ng/mL), insufficient (20–29 ng/mL), and sufficient (≥30 ng/mL). Results: Vitamin D deficiency was present in 64.6% (n=84) of patients. Deficient patients showed significantly higher disease activity scores (mean SLEDAI 14.2±3.9 vs. 9.8±2.7, p<0.001), increased renal involvement (46.4% vs. 16.7%, p=0.043), and higher anti-dsDNA positivity (76.2% vs. 50.0%, p=0.037) compared to sufficient patients. Complement levels (C3 and C4), ESR, and CRP were significantly lower in deficient patients. Conclusion: Vitamin D deficiency is highly prevalent in Bangladeshi SLE patients and is significantly associated with increased disease activity and renal involvement. Routine assessment and supplementation of vitamin D may serve as a simple, cost-effective adjunct in the management of SLE to potentially reduce disease severity and improve outcomes.