FEV1/FVC Severity Stages for Chronic Obstructive Pulmonary Disease

The severity of chronic obstructive pulmonary disease (COPD) is typically determined using the FEV1% predicted (ppFEV1) measure. However, a new severity classification scheme called Staging of Airflow Obstruction by Ratio (STAR), which utilizes the FEV1-FVC ratio, has been proposed as a more robust measure of airflow obstruction. In a study comparing STAR with the GOLD staging system, it was found that STAR provided significant discrimination between the absence of airflow obstruction and stage 1 for various factors such as all-cause mortality, respiratory quality of life, dyspnea, airway wall thickness, exacerbations, and lung function decline. There were no major differences observed for emphysema, small airway disease, and 6-minute-walk distance. The STAR severity classification scheme offers similar discrimination for mortality as the GOLD classification, but with a more consistent gradation of disease severity. Additionally, STAR better differentiates patients' symptoms, disease burden, and prognosis compared to the existing scheme based on ppFEV1, and is less influenced by race/ethnicity and other demographic characteristics.