Induced sputum eosinophilia and pulmonary function tests in ex-smokers with asthma controlled with an inhaled steroid and long-acting beta-agonist therapy.

Introduction: This study aims to investigate the relationship between induced sputum eosinophilia and pulmonary functions in ex-smoker asthma patients controlled with an ICS/LABA therapy.

Materials and methods: Asthma patients who are known to use ICS/LABA regularly for at least three months, without an attack in the last month, quit smoking (5-20 pack-years) and have asthma under control (ACT> 20), and concurrent with induced sputum cytology who had spirometry and lung volume measurements were included in the study. Cytology results, induced sputum eosinophil and neutrophil counts, FEV1 (L), FEV1 (%), FVC (L), FVC (%), RV (L), RV (%) and RV/TLC (%) values of all patients were recorded. The relationship between sputum neutrophil and eosinophil count and pulmonary function test parameters was evaluated.

Result: Seventeen (68%) of the patients were female, eight (32%) were male, and the mean age was 49.7 ± 13.6 years. The mean sputum eosinophil percentage was 9.4 ± 16.7, and the neutrophil percentage was 71.4 ± 20.5. A positive correlation was found between induced sputum eosinophil percentage values and FEV1 (L) (r= +0.472; p= 0.01) and FVC (L) (r= +0.502; p= 0.01). No correlation was found between the FEV1/FVC%, FEV1%, FVC%, RV (L), RV%, and RV/TLC% values and the percentage of induced sputum eosinophils (p> 0.05).

Conclusions: It was observed that controlled asthmatic patients with induced sputum eosinophilia treated with ICS/LABA and who quit smoking had high FVC (L) and FEV1 (L) levels.