SAN FRANCISCO, CA—Patients with chronic inflammatory rheumatic diseases—particularly those with rheumatoid arthritis (RA)—have an increased risk of vitamin D deficiency compared with controls, a study reported at the 2015 ACR/ARHP Annual Meeting.

Ana Urruticoechea, of Hospital Can Misses in Ibiza, Spain, and colleagues studied the association between 25-hydroxyvitamin D (25(OH)D) levels and clinical characteristics from baseline visit data of 2,234 patients with chronic inflammatory rheumatic diseases enrolled in the CARMA (CARdiovascular in rheuMAtology) project. The 10-year prospective study is evaluating the risk of cardiovascular events in patients with RA, ankylosing spondylitis, and psoriatic arthritis, as well as those without chronic inflammatory rheumatic diseases who attend rheumatology outpatient clinics in 67 hospitals in Spain.

A total of 775 patients had RA; 738, ankylosing spondylitis; and 721, psoriatic arthritis. The study also included 677 patients without such diseases. The control group was frequency matched by age with the joint distribution of the three groups. A 25(OH)D deficiency was defined as 25(OH)D vitamin levels <20ng/mL.

Median [p25–p75] 25(OH)D levels were 20.4 (14.4–29.2) ng/mL in patients with RA, 20.9 (13.1–29.0) in those with ankylosing spondylitis, 20.0 (14.0–28.8) in those with psoriatic arthritis, and 24.8 (18.4–32.6) in the controls. Vitamin D deficiency was detected in 40.5%, 39.7%, 40.9%, and 26.7% of the patient groups, respectively (P<0.001).

The investigators found a positive association between RA and 25(OH)D deficiency (odds ratio [OR] 1.46; 95% confidence internal [CI] 1.09, 1.96; P=0.012). However, this association was not observed for ankylosing spondylitis (adjusted OR 1.23; 95% CI 0.85, 1.80) or psoriatic arthritis (adjusted OR 1.32; 95% CI 0.94, 1.84).

When disease activity, severity, or functional impairment parameters were assessed, a “marginally significant association” was observed between 25(OH)D deficiency and patients with RA who were positive for anti-citrullinated protein antibodies (adjusted OR 1.45; 95% CI 0.99, 2.12; P=0.056), and between 25(OH)D deficiency and Bath Ankylosing Spondylitis Functional Index score in patients with ankylosing spondylitis (adjusted OR 1.08; 95% CI 0.99, 1.17; P=0.07), the investigators concluded.