Idiopathic pulmonary fibrosis (IPF) is defined as a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, occurring primarily in older adults, and limited to the lungs. It is characterized by progressive worsening of dyspnea and lung function and is associated with a poor prognosis.~The main symptoms of patients with IPF are dyspnea on exertion and a persistent dry cough or mildly productive cough.~In many IPF patients, cough is often the first symptom, preceding dyspnea on exertion sometimes by years. It affects upwards of 70-85% of patients with IPF.~Chronic obstructive pulmonary disease (prevalence rate 4-18%) and asthma (prevalence rate 5.9-9.9%) are the airway disease whose main symptoms are also dyspnea and cough.~To date, the effect of airway disease has not been well studied in patients with idiopathic pulmonary fibrosis, and the prevalence is unknown in Korea.~Unlike idiopathic pulmonary fibrosis, airway disease is a treatable, modifiable disease, so treatment of these diseases may improve QOL in IPF patients.~Therefore, this study's purpose is A. Identify the prevalence of airway disease in IPF patients B. Identify differences in QOL and symptoms according to presence of airway disease C. Identify the symptomatic improvement after active treatment for the airway diseases
The investigators assess the prevalence of airway disease associated with idiopathic pulmonary fibrosis in Korea, and evaluate the effect of these airway diseases on the symptoms and quality of life of patients with idiopathic pulmonary fibrosis.