A Two-Staged, Risk-Stratified Strategy Combining FEV1/FEV6 and COPD Diagnostic Questionnaire Acts as an Accurate and Cost-Effective COPD Case-Finding Method.

Abstract

Background and objective: Symptom-based questionnaires and handheld lung function devices are widely used for COPD case finding, but the optimal combination remains unclear. This study aimed to compare the diagnostic accuracy (DA) of various combinations of handheld lung function devices and questionnaires and develop a COPD case-finding strategy.

Methods: This cross-sectional, prospective, observational study enrolled participants aged ≥ 40 years with respiratory symptoms and ≥ 10 smoking pack-years. Participants completed three questionnaires (COPD diagnostic questionnaire [CDQ], lung function questionnaire; COPD Population Screener) and 2 handheld lung function devices (peak flow meter, microspirometer), followed by spirometry to confirm COPD (post-bronchodilation FEV₁/FVC < 0.7). DA is assessed using the area under the ROC curve (AUROC).

Results: Among 224 participants, COPD incidence was 29%. Individually, handheld devices showed significantly higher DA than questionnaires (AUROC 0.678-0.69 for questionnaires vs. 0.807 for peak expiratory flow rate [PEFR] and 0.888 for FEV₁/FEV₆; all pairwise p < 0.05). FEV₁/FEV₆-based combinations outperformed PEFR-based combinations (all n = 224; AUROC 0.897-0.903 vs. 0.810-0.818; p < 0.05). The CDQ and FEV₁/FEV₆ combination reached the highest DA (AUROC 0.903). FEV₁/FEV₆ < 0.76 was the optimal cutoff value. A two-staged strategy (sensitivity/specificity 0.82/0.84) was proposed: low-risk participants (CDQ ≤ 13) need no further testing; middle-risk (CDQ 14-26) should undergo FEV₁/FEV₆; and high-risk (CDQ ≥ 27) and middle-risk with FEV₁/FEV₆ < 0.76 require confirmatory spirometry. This approach would reduce misdiagnoses and save costs and time compared to FEV₁/FEV₆ alone.

Conclusion: FEV₁/FEV₆ and CDQ combination achieves the highest DA. A two-staged, risk-stratified strategy combining CDQ and FEV₁/FEV₆ can be accurate and cost-effective to detect at-risk, undiagnosed COPD subjects. External validation is required.