Fig. 1

Kaplan-Meier curves of survival probability according to GOLD (A) or STAR (B) severity stages. Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; STAR, STaging of Airflow obstruction by Ratio.
Kaplan-Meier curves of survival probability according to GOLD (A) or STAR (B) severity stages. Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; STAR, STaging of Airflow obstruction by Ratio.