Objective: To evaluate the association of baseline serum level of vitamin D with disease activity, disability, and radiographic damage over the first year in early rheumatoid arthritis (RA).
Methods: Among early arthritis patients included in the ESPOIR cohort, patients with early RA were evaluated. Levels of 25-hydroxy vitamin D2 and D3 were measured at baseline. Baseline associations between vitamin D level and 28-joint count Disease Activity Score based on erythrocyte sedimentation rate (DAS28-ESR), Health Assessment Questionnaire-Disability Index (HAQ-DI), and van der Heijde modified total Sharp score (mTSS) were assessed. Bivariate analysis was used to assess the association between vitamin D level and radiographic progression (mTSS increased by ≥ 1 point) or disability (HAQ-DI ≥ 0.5) over 12 months. Forward stepwise multiple logistic regression was used to evaluate the independent association of baseline variables and outcomes.
Results: Among 813 patients with early arthritis, data for 645 patients with RA were analyzed. Vitamin D level was < 10 ng/mL (deficiency, group 1), 10-29.9 ng/mL (low level, group 2), and ≥ 30 ng/mL (normal, group 3) for 114 (17.7%), 415 (64.54%), and 114 (17.7%) patients, respectively. At baseline, DAS28-ESR and HAQ-DI were higher with vitamin D deficiency compared with groups 2 and 3 combined (P = 0.007 and P = 0.001, respectively), as was mean mTSS, but not significantly (p = 0.076). On multivariate analysis, baseline vitamin D deficiency was associated with HAQ-DI at 6 months (OR 1.70) and mTSS at 12 months (OR 1.76).
Conclusion: Vitamin D deficiency was associated with more active and severe disease at baseline and may predict disability and radiographic progression over 1 year in early RA patients. [ClinicalTrials.gov: NCT03666091].
Keywords: disability; disease activity; early arthritis; rheumatoid arthritis; severity; vitamin D.