Vitamin D Is Not Associated with Treatment Responses in Patients with Newly Diagnosed Rheumatoid Arthritis

Abstract

Background/Purpose: Vitamin D is known to have immunomodulatory properties and had shown a relationship with susceptibility and disease activity in rheumatoid arthritis (RA). We investigated the relationship between response to treatment and vitamin D levels in patients newly diagnosed with RA.

Methods: This was a retrospective study of 249 patients who were newly diagnosed with RA. They were assessed for 25-hydroxyvitamin D (25OHD) level at diagnosis of RA and after 6 months of treatment. All patients with vitamin D insufficiency (25OHD < 30 ng/ml) received vitamin D supplementation. Correlation between vitamin D levels and disease activity measured by Disease Activity Score 28 calculated with erythrocyte sedimentation rate (DAS28-ESR) at diagnosis and after 6 months were assessed.

Results: The proportion of patient with low, moderate, and high disease activity at diagnosis were 9.2%, 59.4%, and 31.3%, respectively. Mean level of 25OHD was 18.8 ± 11.3 ng/ml. Vitamin D level showed no significant correlation with disease activity at diagnosis with a mean 25OHD value of 17.4 ± 8.6 ng/ml, 19.1 ± 11.3 ng/ml, and 18.8 ± 12.1 ng/ml, respectively. After 6 months of treatment, the proportion of patients in remission, low, moderate, high disease activity were 41.7%, 22.4%, 29.4%, and 6.1%, respectively. Vitamin D significantly increase to mean 25OHD value of 24.7 ± 11.1 ng/ml after 6 months of treatment of RA and vitamin D supplementation in patients with insufficiency. However, it showed no significant correlation with treatment response at 6 months with a mean value of 23.2 ± 11.4 ng/ml, 25.1 ± 10.5 ng/ml, 26.2 ± 10.5 ng/ml, and 26.3 ± 11.9 ng/ml.

Conclusion: Patients showed vitamin D insufficiency at diagnosis of RA, but vitamin D was not correlated with treatment response of RA.