Background and objective: Recently, GLI-2022, a race-neutral reference equation, was proposed for spirometric interpretation. However, the impact of using the GLI-2022 in predicting mortality risk has not been fully investigated. This study determined whether the GOLD grades based on GLI-2022 or race-specific equations are overestimated or underestimated in terms of mortality risk prediction among Korean patients with COPD.
Methods: The participants were enrolled in a prospective COPD cohort study conducted between 2005 and 2022. Patients were classified into GOLD 1 to GOLD 4 based on the post-bronchodilator forced expiratory volume in 1 s (FEV1) % predicted using the GLI-2022, GLI Northeast Asian (GLI-2012), Choi's, and KNHANES-VI reference equations. The risk of all-cause mortality was compared between GOLD grades calculated using different equations.
Results: Among 1989 patients with COPD, 336 died during a median follow-up of 5.0 years (interquartile range, 3.1-7.3). The GLI-2022 estimated FEV1% predicted lower than those of GLI-2012, Choi's, and KNHANES-VI. No differences were found in the discrimination or calibration between the mortality prediction models. Rather, the GLI-2022 equation discriminated the mortality risk between the GOLD 1 and GOLD 2 groups (adjusted hazard ratio [aHR], 1.46; 95% confidence interval [CI], 1.05-2.03); however, the race-specific equations did not (Choi's: aHR, 1.22; 95% CI, 0.80-1.85; KNHANES-VI: aHR, 1.19; 95% CI, 0.77-1.82).
Conclusion: Our results suggest that race-specific equations may overestimate the severity of airflow obstruction in Korean patients with mild COPD, which supports the new recommendation for the use of the GLI-2022.
Keywords: chronic obstructive pulmonary disease; forced expiratory volume; prognosis; prospective studies.
© 2025 Asian Pacific Society of Respirology.