P: Prevent deterioration

	Summary Evidence level Smoking cessation reduces the rate of decline of lung function I Treatment of nicotine dependence is effective and should be offered to smokers in addition to counselling I Influenza vaccination reduces the risk of exacerbations, hospitalisation and death  I Mucolytics may reduce the frequency and duration of exacerbations  II Long-term oxygen therapy (> 15 h/day) prolongs life in hypoxaemic patients (PaO2 < 55 mmHg, or 7.3 kPa) I

Reducing risk factors for COPD is a priority, and smoking is the most important of these. Reduction of exposure to occupational dust, fumes and gases and to indoor and outdoor air pollutants is also recommended⁷. Influenza vaccination reduces the risk of exacerbations and death [evidence level I], while long term oxygen therapy reduces mortality [evidence level I].