BACKGROUND: Vitamin D deficiency is frequently found in patients with Chronic Obstructive Pulmonary Disease (COPD). Vitamin D has antimicrobial, anti-inflammatory and immunomodulatory effects. Therefore, supplementation may prevent COPD exacerbations, particularly in deficient patients.
OBJECTIVES: To assess the effect of vitamin D supplementation on exacerbation rate in vitamin D-deficient patients with COPD.
STUDY DESIGN AND METHODS: We performed a multi-center, double-blind, randomized controlled trial. COPD patients with one or more exacerbations in the preceding year and a vitamin D deficiency (15-50 nmol/L) were randomly allocated in a 1:1 ratio to receive either vitamin D3 16.800 IU or placebo once a week during 1 year. Primary outcome of the study was exacerbation rate. Secondary outcomes included time to first and second exacerbation, time to first and second hospitalization, use of antibiotics and corticosteroids, pulmonary function, maximal respiratory mouth pressure, physical performance, skeletal muscle strength, systemic inflammatory markers, nasal microbiota composition, and quality of life.
RESULTS: The intention-to-treat population consisted of 155 participants. Mean (SD) serum 25-hydroxyvitamine D (25(OH)D) concentrations after one year was 112 (34) nmol/L in the vitamin D group, compared to 42 (17) nmol/L in the placebo group. Vitamin D supplementation did not affect exacerbation rate (incidence rate ratio (IRR):0.90; 95%-confidence interval (95%-CI): 0.67,1.21). In a prespecified subgroup analysis in participants with 25(OH)D levels 15-25 nmol/L (n = 31) no effect of vitamin D supplementation was found (IRR:0.91; 95%-CI:0.43,1.93). No relevant differences were found between the intervention and placebo group in secondary outcomes.
CONCLUSION: Vitamin D supplementation did not reduce exacerbation rate in COPD patients with a vitamin D deficiency.