Comparing the accuracy of CDQ, CAPTURE, LFQ, COPD-PS, COPD-SQ and SCSQ questionnaires for COPD screening in a hospital-facilitated community screening Iranian population

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is a major cause of mortality, with underdiagnosis being a significant global issue. While spirometry is the diagnostic gold standard, it is impractical for widespread screening. This necessitates the use of validated questionnaires for initial risk stratification, though their performance varies across populations. OBJECTIVE: To compare the diagnostic accuracy of six COPD screening questionnaires (CDQ, CAPTURE, LFQ, COPD-PS, COPD-SQ, and SCSQ) against post-bronchodilator spirometry in a hospital-facilitated community screening Iranian population. METHODS: A hospital-facilitated community screening cross-sectional study was conducted on 294 patients aged ≥ 40 years recruited from primary care settings. All participants completed the six questionnaires and underwent spirometry. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and cut-off points that yielded the best balance in our cohort were calculated for each questionnaire, using a post-bronchodilator FEV1/FVC < 0.70 as the gold standard for COPD diagnosis. RESULTS: The prevalence of spirometry-confirmed COPD was 20.4%. All questionnaires showed strong negative correlations with FEV1/FVC ratios (ρ range: -0.58 to -0.70; p < 0.001). The LFQ demonstrated the highest overall accuracy (AUC = 0.768), followed by the SCSQ (AUC = 0.766) and COPD-PS (AUC = 0.755). At established screening cut-offs, all tools showed high sensitivity (89.7% to 96.7%) for ruling out disease, albeit with low specificity (22.2% to 28.9%). A significant difference in AUC values was found between the questionnaires (χ² [5] = 35.16, p < 0.0001). CONCLUSION: The LFQ, SCSQ, and COPD-PS questionnaires demonstrated the highest diagnostic accuracy for COPD screening in this hospital-facilitated community screening cohort. Their high sensitivity shows potential as effective "rule-out" instruments for identifying high-risk individuals in primary care settings who should be referred for confirmatory spirometry. Future validation in a pure primary care setting is recommended.