Broncho-obstructive disorders in sarcoidosis: in search of causes

Objective. Disorders of external respiration function in sarcoidosis are one of the criteria for the severity of the disease. Obstructive disorders are common, but their genesis remains poorly understood. The aim of the study was to assess the frequency of broncho-obstructive disorders in patients with sarcoidosis and the frequency of ICS use. Material and methods. Retrospective analysis of 6841 spirograms of 1697 patients with sarcoidosis, in whom FVC was below 80% of the expected values in 16.1% (1100 patients) of cases, FEV1 — in 22.4% (1534 patients), the FEV1/FVC ratio was below 70% in 872 (12.7%) patients. In 1801 cases (26.3%), patients received ICS. 827 patients underwent a test with bronchodilators. Data were stored and processed in the SPSS-18 program (IBM). Differences were considered significant if p<0.05. Results. FVC was 80% of the predicted value or higher in 653 (79%) patients, and the FEV1/FVC ratio was 70% or higher in 642 (77.6%). The bronchodilator test was positive in 11.4%. With FEV1/FVC < 70%, the frequency of a positive test was 24.9%, and with a normal ratio — 7.5% (p<0.0001). In the presence of concomitant bronchial asthma and COPD, the test was positive in 32.3%, and among the rest — in 8.5%. ICS were more often prescribed in the presence of cough — 50% versus 33.9% (p=0.0001), with FEV1/FVC <70% — 64.3% versus 36.6% (p=0.0001). There was no correlation between the frequency of obstruction and a positive response to bronchodilators between different stages of sarcoidosis. ICS were relatively more often prescribed to patients with stage IV, in which eosinophilia was not observed. Conclusion. Broncho-obstructive syndrome in patients with pulmonary sarcoidosis is more often associated with concomitant diseases, or with fibrosis and deformation of the lung tissue and bronchi, with a low frequency of response to bronchodilators in patients without comorbidity.