Previous literature has reported a special relationship between upper airway conditions and lung diseases has. Sinonasal findings in chronic cough patients have not been thoroughly examined. The purpose of this study is to show paranasal sinus findings and lung function in chronic cough patients without asthma and chest X-ray abnormalities.

The researchers enrolled 1412 patients with persistent cough in this study. Three hundred seventy-six patients were evaluated for further examination, as patients with asthma and chest X-ray abnormality were excluded from the study. Normal control subjects without any chronic respiratory symptoms were also recruited. The researchers examined pulmonary function by spirometry. A bronchial obstruction reversibility test was applied.

The patients with an abnormal soft tissue shadow in the paranasal sinus had significant obstructive lung function. The percent predicted forced expiratory volume in 1 second and the FEV1.0/forced vital capacity ratio negatively correlated with Lund–Mackay CT scores before and after bronchodilator inhalation. There was a statistically significant correlation between pulmonary function and eosinophil count.

The study concluded that patients with chronic cough frequently had paranasal sinus abnormalities. Upper airway examinations should play a part in the management of chronic cough.