The predictive value of handheld peak expiratory flow metre and IPAG questionnaire as a screening tool for COPD among high-risk patients

Abstract

Introduction: Chronic Obstructive pulmonary Disease (COPD) is increasing in Africa due to multiple risk factors like smoking and use of biomass fuels'. There are challenges in the diagnosis of COPD at primary care due to scarcity of spirometers. 

Aim: The objective of the study was to evaluate the predictive value of peak flow rate obtained from a hand-held PEFM and questionnaire as a screening tool of COPD among high risk patients.

Methodology: A cross-sectional study was carried out from August to November 2018. One hundred and Ninety (190) participants with risk factors for COPD were recruited at the Family Medicine Department in LASUTH, Lagos State. The history of risk factors, International primary airway group (IPAG) questionnaire scores, Peak Expiratory Flow Rate (PEFR) and Spirometry values captured. The best cut-off for PEFM as a screening tool was assessed using ROC curve. Results: PEFM had a Sensitivity of 82.3%, Specificity of 51.1%, and PPV of 63.2% and NPV of 73.8%. The IPAG questionnaire reported sensitivity (44.8%) and specificity (23.4%) indicating poor detection rates of COPD when used as a screening tool. Combining the use of a questionnaire and peak flow meter, less than half (43.8%) of those with COPD would be identified. .ROC revealed best cut off for PEFR as 79.5% of expected which would give a sensitivity of 81.3% and specificity of 57.7%.

Conclusion: The mechanical handheld PEFM was determined to have a high sensitivity and PPV, with moderate NPV making it a useful tool in screening for COPD especially in primary care settings where spirometry may not be available.