Patients with idiopathic pulmonary fibrosis and refractory cough have traction bronchiectasis and distorted airway architecture: a retrospective case review study.

Cough is a common and important sign/symptom in patients with idiopathic pulmonary fibrosis (IPF). However, there have been few reports focusing on cough, and the exact mechanisms for cough in patients with IPF have remained unclear. The objective of this study was to investigate the clinical features of IPF patients with refractory cough and to clarify mechanisms for cough in these patients. We retrospectively reviewed the files of patients with the diagnosis of IPF at Kanazawa University Hospital and compared the clinical features of IPF patients with refractory cough with the clinical features of IPF patients without refractory cough. Among a total of 23 patients with IPF, 10 patients (43.5%) had chronic cough. Of the ten patients, seven patients had concomitant conditions that could lead to cough. Of these seven patients, the cough of four patients was resolved after treatment of their concomitant condition. Finally, among the 23 patients there were 6 (26.1%) with refractory cough associated with IPF. Significant differences were seen between the following clinical features of IPF patients with or without refractory cough, respectively, as follows: lower body mass index (BMI; 18.8±2.5 vs. 22.8±2.5 kg/m2, P<0.01), lower forced vital capacity (FVC; 77.5%±30.4% predicted vs. 99.9%±0.53% predicted, P=0.046), and presence of traction bronchiectasis and distorted airway architecture on high-resolution computed tomography (HRCT; 83.3% vs. 11.8%, P<0.01). The difference between the proportions of patients with or without refractory cough with capsaicin cough sensitivity was not significant. Mechanical stress on the airways due to traction bronchiectasis and distorted airway architecture is a possible mechanism for cough in IPF patients.