RESEARCH ARTICLE Case-Finding for Persistent Airway Obstruction in Farmers: A Questionnaire With Optimal Diagnosis Criteria Alicia Guillien, MS, 1 Thibaud E. Soumagne, MD, 2 Marc Puyraveau, PhD, 3 Patrick Berger, MD, PhD, 4 Stéphanie L. Guillot, MD, 5 Fabrice Rannou, MD, 6 Stéphane Jouneau, MD, PhD, 7 Frédéric J. Mauny, MD, PhD, 3 Jean-Jacques Laplante, MD, 8 Jean-Charles Dalphin, MD, 2,9 Bruno Degano, MD, PhD 1,10 Introduction: Appropriate identification of subjects who are candidates for spirometry through case-finding questionnaires may help solve the problem of chronic obstructive pulmonary disease misdiagnosis. The performance of case-finding questionnaires depends at least partially on the characteristics of the population used for their development. The use of an accurate threshold for the forced expiratory volume in 1 second / forced vital capacity ratio to define persistent airway obstruction is also vital in ascertaining chronic obstructive pulmonary disease. Methods: Using a population examined between October 2012 and May 2013 that included a large subset of agricultural workers both exposed and unexposed to tobacco smoking, the authors aimed to select a combination of items that would identify persons most likely to have persistent airway obstruction defined as forced expiratory volume in 1 second / forced vital capacity less than the lower limit of normal according to the Global Lung Initiative–2012 equations. Two thirds of the population (n¼3,397) were randomly selected to develop a questionnaire, and one third (n¼1,698) was reserved for questionnaire validation. Statistical analysis was performed in 2016. Results: The selected items were sex, dyspnea, BMI, tobacco smoking habits, age, history of respiratory diseases, and history of occupation at risk. The C-index of the model was 0.84 (95% CI¼0.80, 0.88) for the development population and 0.76 (95% CI¼0.66, 0.86) for the validation population. Using the selected items in combination, the sensitivity and specificity in identifying persistent airway obstruction were 76% and 77%, respectively, in the development population (and 68% and 73%, respectively, in the validation population) for a threshold value of 2.50%. Conclusions: This seven-item questionnaire is the first developed from a population comprising a large subset of agricultural workers and using the Global Lung Initiative–2012 equations. Am J Prev Med 2017;](]):]]]–]]]. & 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved. INTRODUCTION C hronic obstructive pulmonary disease (COPD) is a preventable and treatable disease that has become one of the leading causes of morbidity and mortality worldwide. 1 Diagnosis of COPD remains challenging, and as few as 20% of those who have COPD are actually identified, whereas more than half of patients who receive a diagnosis of COPD are in fact misdiagnosed. 2,3 Although tobacco smoking is the single most impor- tant causal factor for COPD, 4,5 occupational exposures account for 15%–20% of all COPD cases. 4,6–9 When combined, smoking and occupational exposures may From the 1 Equipe d’Acceuil (EA) 3920, Université de Franche-Comté, Besançon, France; 2 Service de Pneumologie, Centre Hospitalier Regional Universitaire (CHRU), Besançon, France; 3 Centre de Méthodologie Clin- ique, CHRU, Besançon, France; 4 Service d’Explorations Fonctionnelles Respiratoires, Centre Hospitalier Universitaire (CHU) de Bordeaux, Pessac, France; 5 Service d’Explorations Fonctionnelles Respiratoires, CHU, Rennes, France; 6 Service d’Explorations Fonctionnelles Respiratoires, CHU, Brest, France; 7 Service de Pneumologie, CHU, Rennes, France; 8 Mutualité Sociale Agricole, Besançon, France; 9 Unité Mixte de Recherche du Centre National de la Recherche Scientifique Chrono-Environnement, Université de Franche-Comté, Besançon, France; and 10 Service d’Explora- tions Fonctionnelles Respiratoires, CHRU, Besançon, France Address correspondence to: Bruno Degano, MD, PhD, Physiologie- Explorations Fonctionnelles, CHU Jean Minjoz, 25030 Besançon Cedex, France. E-mail: bruno.degano@univ-fcomte.fr. 0749-3797/$36.00 https://doi.org/10.1016/j.amepre.2017.06.031 & 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved. Am J Prev Med 2017;](]):]]]–]]] 1