Distinguishing asthma and chronic obstructive pulmonary disease: why, why not and how?

What we need to knowWhat are the essential differences in the inflammatory process that lead to different pathological outcomes in asthma and chronic obstructive pulmonary disease (COPD)? What factors cause some patients with asthma to have clinical features indistinguishable from COPD, and should these patients be treated differently from those with early‐onset, atopic asthma? What should be added to FEV 1 improvement after bronchodilator to enhance the ability of spirometry to distinguish between asthma and COPD? Why is disturbed gas exchange characteristic of stable COPD but rare in asthma? Why and when does COPD become a systemic disease with multiorgan dysfunction, while asthma generally does not? Does the response to bronchodilators in asthma and COPD predict prognosis and response to other interventions? Do people with asthma (airway obstruction, hyper‐responsiveness and atopy) and COPD (fixed airflow limitation) have different natural histories, responses to treatment and prognoses?What we need to doEvaluate new diagnostic tools (eg, indirect markers of inflammation) for asthma and COPD. Target older people in epidemiological studies to identify and describe the extent of asthma. Initiate community awareness programs to help older people with dyspnoea recognise they may have symptoms of asthma or COPD that should be assessed by a doctor. Define the clinical and physiological features of asthma and COPD in older people that indicate when and which treatments will achieve maximum benefit with least harm. Develop strategies for better, patient‐focused care of people with severe airway disease, concentrating on device use, action plans, side effects, end‐of‐life decisions, exercise and independence in activities of daily living. Maintain research into new drugs and targets for preventing progressive loss of lung function in asthma and COPD.