Vitamin D deficiency is associated with impaired disease control in asthma–COPD overlap syndrome patients

Abstract

Balázs Odler,1 István Ivancsó,1 Vivien Somogyi,1 Kálmán Benke,2 Lilla Tamási,1 Gabriella Gálffy,1 Balázs Szalay,3 Veronika Müller11Department of Pulmonology, 2Heart and Vascular Centre, 3Department of Laboratory Medicine, Semmelweis University, Budapest, HungaryIntroduction: The association between vitamin D and clinical parameters in obstructive lung diseases (OLDs), including COPD and bronchial asthma, was previously investigated. As asthma–COPD overlap syndrome (ACOS) is a new clinical entity, the prevalence of vitamin D levels in ACOS is unknown.Aim: Our aim was to assess the levels of circulating vitamin D (25-hydroxyvitamin D [25(OH)D]) in different OLDs, including ACOS patients, and its correlation with clinical parameters.Methods: A total of 106 men and women (control, n=21; asthma, n=44; COPD, n=21; and ACOS, n=20) were involved in the study. All patients underwent detailed clinical examinations; disease control and severity was assessed by disease-specific questionnaires (COPD assessment test, asthma control test, and modified Medical Research Council); furthermore, 25(OH)D levels were measured in all patients.Results: The 25(OH)D level was significantly lower in ACOS and COPD groups compared to asthma group (16.86±1.79 ng/mL and 14.27±1.88 ng/mL vs 25.66±1.91 ng/mL). A positive correlation was found between 25(OH)D level and forced expiratory volume in 1 second (r=0.4433; P<0.0001), forced vital capacity (FVC) (r=0.3741; P=0.0004), forced expiratory flow between 25% and 75% of FVC (r=0.4179; P<0.0001), and peak expiratory flow (r=0.4846; P<0.0001) in OLD patient groups. Asthma control test total scores and the 25(OH)D level showed a positive correlation in the ACOS (r=0.4761; P=0.0339) but not in the asthma group. Higher COPD assessment test total scores correlated with decreased 25(OH)D in ACOS (r=-0.4446; P=0.0495); however, this was not observed in the COPD group.Conclusion: Vitamin D deficiency is present in ACOS patients and circulating 25(OH)D level may affect disease control and severity.Keywords: ACOS, obstructive lung disease, CAT