Optimal spirometry thresholds for the prediction of chronic airflow obstruction: a multinational longitudinal study.

Introduction: Chronic airflow obstruction is key for COPD diagnosis, but strategies for its early detection are limited. We aimed to define the optimal z-score thresholds for spirometry parameters to discriminate chronic airflow obstruction incidence.

Methods: The Burden of Obstructive Lung Disease study is a multinational cohort study.