Screening for undiagnosed COPD; accuracy of different strategies among hypertensive patients in Brazil: a Breathe Well study

Aim:To identify the most effective screening strategy for identifying undiagnosed COPD among hypertensive patients in primary care. Methods: Cross-sectional study in nine Basic Health Units in Brazil, with hypertensive patients aged ≥40 years completing index tests (screening questionnaires [CDQ, CAPTURE, Symptom-based questionnaire, COPD-SQ], microspirometer [COPD-6] and peak flow [Mini Wright) and the reference test (ndd Easy On-PC spirometer). Cases were defined as those below the lower limit of normal (LLN-GLI) on the reference test. Interim analysis assessed the test performance of the CAPTURE questionnaire against the reference test; data regarding sensitivity and specificity of all screening tests and strategies will be presented at the conference. Results: The study recruited 1,232 participants, with a mean age of 61.9 (± 10.4) years, 67% (n=832) were female, and 48.9% (n=603) were never smokers. 8.3% (n=98) of participants had spirometry-confirmed airflow obstruction. The CAPTURE tool had a sensitivity of 63.3% and a specificity of 45.4% using a cut-point of ≥2, with an area under the ROC curve of C=0.58 (95% CI 0.52 to 0.63) (Table 1). Conclusion: The prevalence of undiagnosed COPD in our sample was less than 10%. The CAPTURE tool correctly identified approximately two thirds of patients with airflow obstruction, but only had moderate discriminatory ability. In our Brazilian primary care population, CAPTURE had lower sensitivity compared with previous studies in other countries, which may be explained by differences in the undiagnosed COPD population. The test performance of all index tests and strategies will be analysed in the near future. Identifying patients with previously undiagnosed COPD has enabled them to be referred into a new care pathway. Implementation Science/Service Development Research Ideas on Respiratory Conditions and Tobacco Dependency Abstract Declaration of Interest The authors declare no conflicts of interest. The NIHR Global Health Research (GHR) Programme is funded through UK Official Development Assistance (ODA) via the Department of Health and Social Care (DHSC). The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. We gratefully acknowledge IPCRG for introducing us to the primary care networks involved in this study and for its continued facilitation of clinical engagement. References and Clinical Trial Registry Information The study is registered at http://www.isrctn.com (ISRCTN13357135).