Objective: To evaluate the association of baseline serum level of vitamin D (vitD) 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. 25OH vitamin D2D3 level was measured at baseline. Baseline associations between vitD level and 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 vitD 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 RA patients were analyzed. VitD level was <10 ng/ml (deficiency, group 1), 10-30 ng/ml (low level, group 2) and ≥30 ng/ml (normal, group 3) for 114 (17.7%), 415 (64.6%), and 114 (17.7%) patients, respectively. At baseline, DAS28-ESR and HAQ-DI were higher with vitD deficiency as 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 vitD deficiency was associated with HAQ-DI at 6 months (OR=1.70) and mTSS at 12 months (OR=1.76).
Conclusion: VitD 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.