Background The purpose of the study was to define the associations between serum level of 25-hydroxyvitamin D (25(OH)D) and disease activity in patients with rheumatoid arthritis (RA).
Objectives The study group comprised 93 patients aged 27–80 years suffering from RA (74.2% women) and 93 controls.
Methods The levels of rheumatoid factor (RF) and C-reactive protein (CRP) were measured by immunoturbidimetric assay. Erythrocyte sedimentation rate (ESR) was measured by Westergren method. Serum 25(OH)Dtotal level was determined by electrochemiluminescence (ECL) method. The optimal vitamin D status was defined when serum 25(OH)D level was 30–50 ng/ml.
Results In general, 54.8% of RA patients revealed vitamin D deficiency, and 37.6% - vitamin D insufficiency. No significant difference was found when mean serum 25(OH)D levels in RA patients and healthy controls where compared. 25(OH)D levels appeared markedly lower in patients with the highest activity of RA compared to values noted in patients with the minimal RA activity (16.55±9.26 vs 22.59±9.74 ng/ml, p<0.05). In RA patients 25(OH)D levels were significantly and negatively associated with markers of disease activity (DAS28-ESR (β = -0.33; 95% CI =0.05, -0.01), CRP (β = -0.23; 95% CI = -0.72; 0.00), and ESR (β = -0.26; 95% CI = -0.78; -0.10). All these associations remained statistically significant after adjustment for gender, age and BMI.
Conclusions Vitamin D deficiency should be considered as an important predictor of the high RA activity (AUROC =0.67; 95% CI =0.513–0.83, P=0.05).
Disclosure of Interest None declared