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.