| A | Symptom-based | A change for at least two consecutive days in two or more major symptoms (dyspnoea, sputum purulence and sputum amount) or any one major symptom plus any one or more minor symptoms (colds, wheeze, sore throat and cough) |
| B | Symptom-based | A change for at least two consecutive days in two or more major symptoms (dyspnoea, sputum purulence and sputum amount) |
| C | Event-based | A worsening of respiratory symptoms for which the patient initiates a course of prednisolone and/or antibiotics |
| D | Event-based | A worsening of respiratory symptoms for which the patient pays an unscheduled visit to a general practitioner or a chest physician (including emergency service or outpatient clinic) |