High prevalence of vitamin D deficiency and insufficiency in patients with rheumatic diseases

Background: Vitamin D deficiency has been reported in patients with rheumatic diseases, and it may play a role in the inflammatory process. Objectives: To assess vitamin D status in rheumatologic patients treated with either biologic or disease-modifying antirheumatic drugs (DMARDs) therapy. Methods: In this cross-sectional study, serum vitamin D in consecutive patients who were visited in two rheumatology ambulatories were measured. Patients receiving vitamin D supplementation were excluded. Vitamin D levels >30 ng/mL (75 nmol/L) were considered normal, insufficiency is defined as a concentration of 20 to 30 ng/mL (50 to 75 nmol/L), and deficiency when levels were <20 ng/mL (50 nmol/L). Results: A total of 136 patients (M/F: 36/100; Median age: 60 years, range 26-84; Rheumatoid arthritis: 87; Psoriatic arthritis: 38; Ankylosing spondilitis: 8; Polymyalgia rheumatica: 3) were enrolled, including 75 patients receiving biologic therapy and 56 patients DMARDs. Vitamin D deficiency was detected in 56 (41.2%) patients, and insufficiency in further 28 (20.6%) cases, accounting for an overall 61.8% deficiency/insufficiency. The prevalence of Vitamin D deficiency (50.7% vs 29.5%; p = 0.01), insufficiency (28% vs 11.5%; p = 0.02), and deficiency-insufficiency (78.7% vs 41%; p < 0.001) was significantly higher in patients receiving biologic therapy than in those treated with DMARDs. Conclusions: Prevalence of Vitamin D deficiency/insufficiency was very high in rheumatic disease patients, particularly in those receiving a biologic therapy who, most likely, had a more aggressive disease. Vitamin D supplementation could be useful in these patients.