GECo: Implementation and Effectiveness of COPD Case-Finding in Low and Middle Income Countries

The investigators will determine whether case-finding for COPD can be facilitated using 5-item questionnaires with and without a measurement of Peak-Flow. The investigators hypothesise that 5-item questionnaires will be a valid case-finding tool for COPD in LMIC and will be acceptable and feasible for use in these settings. 1. Clinical Aim: Determine the diagnostic accuracy of the case-finding questionnaires with and without PEF. 2. Implementation Aim: Assess the appropriateness, acceptability and feasibility of using questionnaires and PEF to identify COPD cases from the perspective of local community members, community health workers, local health centre physicians and ministries of health. The design of the intervention will be informed by formative work prior to commencement of the main study. Study fieldworkers will enroll and screen a randomly-selected age- and sex-stratified population sample of adults aged ≥40 years; a total of 10,500 between the following three countries in the catchment areas of existing community census areas in Bhaktapur (Nepal), Lima (Peru), and Nakaseke (Uganda). The investigators will report the sensitivity, specificity and positive predictive value of the case-finding questionnaire, with and without PEF, in relation to a gold standard COPD diagnosis made at spirometry (post-bronchodilator FEV1/VC ratio \<LLN, with a history of significant respiratory exposure to tobacco smoke or biomass). The investigators will construct ROC curves to visualise trade-offs in sensitivity and specificity across a range of questionnaire cut off values. The investigators will also examine the feasibility of implementing a 5 item questionnaire +/- PEF intervention at scale.