Assessment of Vitamin D3 level in patients of rheumatoid arthritis and its relationship with disease activity using DAS 28-CRP in tertiary care center of Bihar, India

Background: Rheumatoid arthritis (RA) is most common type of inflammatory arthritis. It is chronic autoimmune disease that affects joints as well as extra-articular structures. The prevalence of this condition could be due to both genetic and non-genetic factors (e.g., environmental, viral, and hormonal).
Aims and Objectives: The aim of the study was to determine and correlate 25(OH) D level with disease severity in patients of RA.
Materials and Methods: The prospective observational study consists of 70 patients of RA and 70 healthy controls. Assessed level of 25(OH) D, C-reactive protein (CRP), anti-cyclic citrullinated peptide (CCP), erythrocyte sedimentation rate (ESR), and Disease Activity Score (DAS) 28-CRP score were compared in both cases and controls. Correlation of Vitamin D level with parameters such as CRP, Anti-CCP, and ESR was performed. Correlation between Vitamin D level deficiency and disease activity among the RA patients was assessed.
Results: The mean age of patients in the RA group was 37.77±13.31 years. The mean CRP in cases was 40.57±25.94 mg/L and in controls was 3.26±1.95 mg/L with significant intergroup difference (P<0.001). The mean anti-CCP in cases was 62.18±27.21 U/mL and in controls was 4.99±1.52 U/mL with significant intergroup difference (P<0.001). The mean 25(OH) D level in cases was 12.65±5.88 and in controls was 32.18±10.22. The 25(OH) D was significantly decreased in cases than controls (P<0.001). A significant inverse relationship between serum 25(OH) D levels and DAS28 was observed. Receiver operating characteristic (ROC) curves results showed that 25(OH) D<11.7 ng/mL indicates severe disease activity (Area under ROC curve=84%, Sensitivity 77.78%, and specificity 83.33%,). 25(OH) D between 11.7 ng/mL and 19.83 ng/mL indicates moderate disease activity. 25(OH) D˃19.83 ng/mL indicates low disease activity value below 4.13 is alarming situation.
Conclusion: The study reveals high prevalence of Vitamin D deficiency and insufficiency in RA patients. There is also significant inverse correlation exist between serum Vitamin D levels and RA disease activity. Vitamin D level is good disease activity predictor in patients of RA.