Distribution and prognostic validity of the new Global Initiative for Chronic Obstructive Lung Disease grading classification

Abstract

Background: The new Global Initiative for Chronic Obstructive Lung Disease (GOLD) update includes airflow limitation, history of COPD exacerbations, and symptoms to classify and grade COPD severity. We aimed to determine their distribution in 11 well-defined COPD cohorts and their prognostic validity up to 10 years to predict time to death.

Methods: Spirometry in all 11 cohorts was postbronchodilator. Survival analysis and C statistics were used to compare the two GOLD systems by varying time points.

Results: Of 3,633 patients, 1,064 (33.6%) were in new GOLD patient group A (low risk, less symptoms), 515 (16.3%) were B (low risk, more symptoms), 561 (17.7%) were C (high risk, less symptoms), and 1,023 (32.3%) were D (high risk, more symptoms). There was great heterogeneity of this distribution within the cohorts ( x (2) , P < .01). No differences were seen in the C statistics of old vs new GOLD grading to predict mortality at 1 year (0.635 vs 0.639, P = .53), at 3 years (0.637 vs 0.645, P = .21), or at 10 years (0.639 vs 0.642, P = .76).

Conclusions: The new GOLD grading produces an uneven split of the COPD population, one third each in A and D patient groups, and its prognostic validity to predict time to death is no different than the old GOLD staging based in spirometry only.