Vitamin D and responses to inhaled fluticasone in severe chronic obstructive pulmonary disease

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) demonstrate variable responses to inhaled corticosteroids (ICS). The factors contributing to this variability are not well understood. Data from patients with asthma have suggested that low 25-hydroxyvitamin D [25(OH)D] levels contribute to a lack of ICS response in asthma. The objective of this study was to determine whether serum levels of 25(OH)D were related to ICS responses in patients with COPD. METHODS: A total of 60 exsmokers with severe COPD (mean forced expiratory volume in one second [FEV(1)] 1.07 L, 36% of predicted) spent 4 weeks free of any ICS, followed by 4 weeks of ICS use (fluticasone propionate 500 μg twice daily). Spirometry was performed prior to and after 4 weeks of ICS use. Blood 25(OH)D levels were measured prior to ICS use and examined for relationships to changes in FEV(1) following the 4 weeks of ICS use. RESULTS: The mean 25(OH)D level was 23.3 ± 9.3 ng/mL. There was a high prevalence of vitamin D insufficiency (35%) and deficiency (40%). There was no relationship between baseline 25(OH)D and changes in FEV(1) following 4 weeks of ICS. CONCLUSION: Baseline 25(OH)D does not contribute to the variation in short-term FEV(1) responses to ICS in patients with severe COPD.