In this study we evaluate the effect of Pirfenidone on cough and quality of life in patients with idiopathic pulmonary fibrosis (IPF) that are treated with Pirfenidone in daily practice. The hypothesis is that Pirfenidone will decrease cough and increase quality of life.

Rationale: Idiopathic Pulmonary Fibrosis (IPF) is a progressive fibrotic lung disease of unknown cause with a median survival of 3-5 years. No curative treatment exists, though in 2011 Pirfenidone was approved for the treatment of IPF as it appeared to slow down the decline in lung function. In patients with IPF, the most common symptoms are cough and breathlessness. Cough is not only a major distressing and disabling symptom but also an independent predictor of disease progression and death in IPF. Recent preliminary data suggest a possible effect of Pirfenidone on cough.

Objective: In this study we want to objectively measure the effect of Pirfenidone on cough in patients with IPF that are treated with Pirfenidone in daily practice .

Study design: This is a prospective, observational, international multicenter study.

Intervention: Objective 24-hour cough frequency will be recorded using the Leicester Cough Monitor (LCM), a validated ambulatory cough monitoring system, prior to starting with Pirfenidone treatment. The cough recording will be repeated at 4 weeks and at 12 weeks during treatment with Pirfenidone. At the days of cough recording, patients will be asked to fill in questionnaires related to cough and to quality of life. Patient will be treated according to normal clinical practice at their Physician's discretion.

Main study parameters/endpoints: The primary endpoint is change in cough frequency measured by the Leicester cough monitor at week 12 compared to baseline. Secondary endpoints look at the relationships between cough, change in cough, quality of life and clinical parameters.

Inclusion Criteria:

• Diagnosis of IPF according to American Thoracic Society (ATS) / European Respiratory Society (ERS) criteria (5), definite and probable patients will be eligible
• Written informed consent
• Daily cough related to IPF (exclusion of other causes) present > 8 weeks
• cough score on visual analogue scale of ≥ 40 mm.
• Carbon monoxide transfer capacity corrected for hemoglobin (TLCOc) ≥ 30% and Forced Vital Capacity (FVC) ≥ 50%
• Pirfenidone therapy about to be initiated
• if a history positive for Gastro Esophageal Reflux (GER), using proton pump inhibitor (PPI) > 4 weeks

Exclusion Criteria:

• Opiates, antitussive medication, antihistamines, steroids > equivalent of 10 mg prednisone or N-acetylcysteine (NAC) within two weeks before study
• Change of steroid < 10 mg, inhalation steroids within 2 weeks of the study - History of bronchial hyper responsiveness or asthma or relevant airway obstruction (FEV1/FVC < 0.7)
• within 6 weeks of the start signs of respiratory tract infection, change of sputum production and fever.

Patients with IPF about to start on Pirfenidone according to regular practice in the participating University Hospitals