A Novel Model-Based Questionnaire Based on Low-Dose CT Screening Data for Chronic Obstructive Pulmonary Disease Diagnosis in Shimane, Japan

Abstract

Purpose: Although there have been many reports on the use of respiratory function tests and questionnaires for creating chronic obstructive pulmonary disease (COPD) questionnaires, there have been no reports on the effectiveness of questionnaires using computed tomography (CT) screening data. We aimed to validate the International Primary Care Airways Group (IPAG) questionnaire and to propose a novel COPD screening questionnaire based on the CT screening data of Japanese participants.

Patients and methods: Low-dose CT screening was performed for early detection of lung cancer and COPD since 2009 in Shimane, Japan, and clinical information was collected using an original questionnaire that included all the IPAG questionnaire items and eight additional items (for eg, on dyspnea) during CT screening. Participants with emphysema, smoking history, and respiratory symptoms were instructed to undergo a respiratory function test. The participants with the forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) <0.7 on the respiratory function test were diagnosed with COPD, and 11,458 participants underwent CT screening from 2013 to 2016 and were enrolled and filtered using <22.5 pack-years. Data from 3252 participants were selected for the final analysis. The receiver operating characteristic curve determined the best cutoff points for discriminating patients with COPD. The efficacy of the questionnaire items was determined using logistic regression analysis.

Results: The best cutoff point for the Japanese IPAG questionnaire was 23. The logistic regression analysis revealed significant differences in the question items of "age", "pack-year", "cough", "phlegm", and "feeling of dyspnea". COPD-CT questionnaire was developed based on the CT screening data. The COPD predicted value was determined using the regression model obtained in this study.

Conclusion: The IPAG questionnaire had low specificity for discriminating COPD in Japanese patients. A novel questionnaire (COPD-CT) and the COPD predicted value based on the CT screening data was developed.

Keywords: Japanese population; pack-years; prediction model; validation.

Figure 1

Protocol for CT screening in Shimane, Japan.

Figure 2

Questionnaire created by our department and used for CT screening in Shimane, Japan. IPAG questionnaire items represent the interview questions that are the same as in the IPAG questionnaire.

Figure 3

ROC curve for pack-year (sample, n = 11,458). Area under ROC curve = 0.88588. A cut-off of 22.50 pack-year showed a sensitivity of 91.3% and a specificity of 73.0%.

Figure 4

ROC curve for the COPD questionnaire of IPAG (subset sample, n = 3252). Area under ROC curve = 0.67648. A cut-off score of 23.00 showed a sensitivity of 60.4% and a specificity of 63.8%.