Vitamin D deficiency in patients with either rheumatic diseases or inflammatory bowel diseases on biologic therapy

Vitamin D deficiency has been reported in patients with chronic inflammatory conditions, such as rheumatic and inflammatory bowel diseases (IBD). We evaluated the role of biologic therapy on vitamin D, calcium and parathormone (PTH) levels. This cross-sectional study enrolled consecutive patients with either rheumatic diseases or IBD who underwent an ambulatory visit. Patients receiving vitamin D/calcium supplementation were excluded. Vitamin D deficiency or insufficiency was diagnosed when values were <20 ng/mL and 21-29 ng/ml, respectively. Patients were sub-grouped according to biologic therapy. A multivariate analysis was performed. Two-hundred patients, including 136 with a rheumatic disease (M/F 37/99; mean age 60.7 ± 12.9 years) and 64 with IBD (M/F 41/23; Mean age 49.6 ± 13.1 years) were enrolled. Vitamin D deficiency/insufficiency was detected in as many as 63.5 % patients, being 61.8 and 67.2 % in patients with either rheumatic diseases or IBD, respectively. The prevalence of vitamin D deficiency/insufficiency was higher in those receiving biologics than other therapies (78.3 vs 43.2 %; p < 0.0001), in either rheumatic diseases (78.7 vs 41 %; p < 0.0001) or IBD (75 vs 50 %; p = 0.03) group. At multivariate analysis, only biologic therapy was independently associated with vitamin D deficit (OR 4.61; p = 0.001). Patients with vitamin D deficiency/insufficiency had hypocalcemia more frequently than controls (22.8 vs 10.9 %; p = 0.03), while PTH values did not differ significantly. This study finds that the prevalence of vitamin D deficiency/insufficiency was very high in patients with either rheumatic diseases or IBD receiving a biologic therapy.