Handheld device-questionnaire combo improves COPD diagnosis

In patients with suspected chronic obstructive pulmonary disease (COPD), the combination of FEV₁/FEV₆ and COPD diagnostic questionnaire (CDQ) demonstrates the highest diagnostic accuracy as well as cost-effectiveness in detecting at-risk individuals, according to a Taiwan study.

“Combining a questionnaire and a handheld lung function device is a more effective strategy for identifying individuals at increased risk for COPD,” the researchers said. “However, questionnaires used alone are still valuable tools for predicting COPD.” [Am J Respir Crit Care Med 2018;198:1130-1139]

Of the 224 participants aged ≥40 years with respiratory symptoms and ≥10 smoking pack-years, 29 percent were diagnosed with COPD. They completed three questionnaires (ie, CDQ, lung function questionnaire, and COPD Population Screener) and used two handheld lung function devices, followed by spirometry, to confirm COPD (post-bronchodilation FEV₁/FVC <0.7).

Finally, the researchers assessed the diagnostic accuracy of these combinations using the area under the receiver operating characteristic curve (AUROC).

Individually, handheld devices were more accurate than questionnaires in detecting COPD (AUROC, 0.678–0.69 for questionnaires vs 0.807 for peak expiratory flow rate [PEFR] and 0.888 for FEV₁/FEV₆; p<0.01 for all). [Respirology 2025;30:493-503]

Comparisons of the combined strategies showed that FEV₁/FEV₆-based combinations had greater diagnostic accuracy than PEFR-based combinations (AUROC, 0.897–0.903 vs 0.810–0.818; p<0.05). The combination of CDQ and FEV₁/FEV₆ achieved the highest accuracy (AUROC, 0.903), and FEV₁/FEV₆ <0.76 was set as the optimal cutoff value.

Two-staged approach

The researchers then proposed a two-staged strategy (sensitivity, 0.82; specificity, 0.84): low-risk participants (CDQ ≤13) need no further testing; middle-risk (CDQ 14–26) must undergo FEV₁/FEV₆; and high-risk (CDQ ≥27) and middle-risk with FEV₁/FEV₆ <0.76 require confirmatory spirometry. Such an approach would prevent misdiagnoses and save time and costs compared with FEV₁/FEV₆ alone.

“Regular spirometry, although accurate, often consumes significant medical resources and yields a low diagnostic rate, making it inefficient for widespread COPD detection,” the researchers said. [J Am Med Assoc 2016;315:1372-1377]

The use of single tools, such as questionnaires or handheld lung function devices, is still the cheapest option, demonstrating good accuracy depending on the tool used. In this regard, handheld lung function devices usually outperform questionnaires. [BMJ Open 2021;11:e051811; npj Prim Care Respir Med 2022;32:55; npj Prim Care Respir Med 2015;25:15056]

The current findings align with those of previous studies, which showed better diagnostic performance and cost-effectiveness with combined modalities by improving the identification of COPD patients. [BMJ Open 2021;11:e051811; npj Prim Care Respir Med 2022;32:55]

The proposed strategy demonstrates its feasibility for a wide implementation, especially in areas with limited resources, according to the researchers.

"Handheld lung function devices, rather than questionnaires, play a crucial role in determining diagnostic accuracy, and the FEV₁/FEV₆ is better than PEFR,” the researchers said. “A two-staged, risk-stratified combined modality using CDQ and FEV₁/FEV₆ can be an accurate and cost-effective case-finding strategy for COPD detection.” 

This strategy, however, warrants external validation and implementation in primary care to detect at-risk, undiagnosed COPD in Taiwan, they added.