C2.5 COPD case finding
The US Preventive Services Task Force reviewed the evidence on screening asymptomatic adults for COPD using questionnaires or office-based screening pulmonary function testing. The review found no direct evidence to determine the benefits and harms of screening or to determine the benefits of treatment in screen-detected populations. On this basis screening of asymptomatic adults was not recommended (Guirguis-Blake 2016, U. S. Preventive Services Task Force 2016).
Simple lung function tools can assist practitioners in the case finding of individuals who have undiagnosed COPD. The devices measure the amount of exhaled air in the first 1 and 6 seconds of expiration (FEV1, FEV6) and calculate FEV1/FEV6, which is the ratio of the amount of air forcibly exhaled in the first second relative to the first 6 seconds. Lung Foundation Australia’s Position Paper on the Use of COPD screening devices for targeted COPD case finding in community settings, http://lungfoundation.com.au/wp-content/uploads/2014/02/Position-Paper.pdf recommends that previously undiagnosed individuals aged 35 years or older should be assessed with the symptom checklist, followed by a COPD screening device with an FEV1/FEV6 cut-off < 0.75. Individuals with an FEV1/FEV6 ratio < 0.75 should undergo formal diagnostic spirometry. Symptomatic individuals with an FEV1/FEV6 ratio ≥ 0.75 should be encouraged to visit their general practitioner as they may be at risk of other diseases or lung conditions and may require more formalised testing. COPD is commonly undiagnosed, until presentation requiring a hospital admission. A review of 39 studies with a variety of case finding strategies, including five studies comparing earlier diagnostic strategies with usual care, has found that postal questionnaire approaches had poor results, while active opportunistic case finding through primary care had greater chance of detection (Haroon 2015). Practice led symptom questionnaires of patients clinically suspected to have COPD, followed by diagnostic assessment, had the best diagnostic yields. Widespread population screening for COPD is not recommended (Guirguis-Blake 2016, U. S. Preventive Services Task Force 2016).
 Level of evidence could not be assigned due to heterogeneity