Evaluation of Serum 25-Hydroxyvitamin D Levels in Patients with Rheumatological Diseases: A Single-Center Cross-Sectional Study

Öz

Background: Vitamin D plays a crucial role in immune regulation, and vitamin D deficiency is frequently reported in patients with autoimmune and inflammatory rheumatological diseases. However, real-world data comparing vitamin D status across different, well-defined rheumatological disease entities remain limited. This study aimed to evaluate serum 25-hydroxyvitamin D [25(OH)D] levels in patients with confirmed rheumatological diseases and to compare vitamin D status among disease groups. Methods: This single-center, cross-sectional observational study was conducted at a tertiary referral hospital. Adult patients with confirmed autoimmune or inflammatory rheumatological diseases who were evaluated between 1 January 2024 and 31 December 2025 and had available serum 25(OH)D measurements were retrospectively screened, and 460 patients were assessed for eligibility. After exclusion of patients with polymyalgia rheumatica, other heterogeneous connective tissue diseases, non-specific musculoskeletal complaints, incomplete diagnostic evaluation, or missing data, 424 patients were included in the final analysis. Serum 25(OH)D levels were categorized as deficient (<20 ng/mL), insufficient (20–29.9 ng/mL), or sufficient (≥30 ng/mL). Group comparisons were performed using the Kruskal–Wallis test for continuous variables and the chi-square test for categorical variables, followed by post hoc analyses where appropriate. Results: A total of 424 patients were included in the study. Vitamin D deficiency was identified in the majority of patients, and more than four-fifths of the cohort exhibited serum 25(OH)D levels below 30 ng/mL. Serum 25(OH)D concentrations differed significantly among rheumatological disease groups (p < 0.001). Patients with Sjögren’s syndrome demonstrated significantly higher median vitamin D levels compared with those with rheumatoid arthritis and Behçet disease. Conclusions: Vitamin D deficiency and insufficiency are highly prevalent among patients with autoimmune and inflammatory rheumatological diseases, with significant variability observed across disease entities. These findings support the importance of routine assessment of vitamin D status in rheumatology practice and highlight the need for disease-specific and individualized management strategies

Anahtar Kelimeler

• Vitamin D deficiency
• rheumatological diseases
• autoimmunity
• cross-sectional study.

Kaynakça

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