A Predicted FEV1/FVC Model Based on a Simple Respiratory Questionnaire for Early Diagnosis of COPD in Shimane Cohort,...

Early detection of chronic obstructive pulmonary disease (COPD) remains challenging in primary care settings where spirometry is not always available. We aimed to develop a simple questionnaire-based approach to estimate the forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) ratio for COPD screening.

This was a single-center retrospective observational study based on the Shimane cohort. From 2008 to 2014, respiratory questionnaires and spirometry were performed during health check-ups of individuals aged ≥40 years. Among 2230 participants who underwent spirometry, 727 current or former smokers without a history of bronchial asthma were included for model development. Multiple regression analysis was used to identify questionnaire items associated with FEV₁/FVC and to construct a simplified estimation model.

Four variables-age, smoking intensity, exertional dyspnea, and paroxysmal dyspnea-were independently associated with FEV₁/FVC and were incorporated into the model. The model demonstrated modest explanatory power (R² = 0.136), with no significant lack-of-fit (F = 1.152). Based on these variables, a simple four-item model enabled estimation of FEV₁/FVC and identification of individuals at risk for airflow limitation.

We developed a simple questionnaire-based model to estimate FEV₁/FVC using four easily obtainable variables. Although the model is exploratory and requires external validation, it may serve as a practical screening tool to identify individuals at risk for COPD in settings where spirometry is not readily available.