Mortality prediction in chronic obstructive pulmonary disease comparing GOLD2015 and GOLD2019 staging: a pooled analysis of individual patient data

In 2019, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) proposed a clinical grading system for patients with chronic obstructive pulmonary disease (COPD) with 4 categories (A-D) based on symptoms and exacerbation history.As part of the COPD Cohorts Collaborative International Assessment (3CIA) initiative, we aim to compare mortality prediction of 2015 and 2019 COPD GOLD staging systems.We studied 17 139 COPD patients from the 3CIA study, selecting those with complete data. Patients were classified by the 2015 and 2019 GOLD ABCD systems and we compared the predictive ability for 5-year mortality of both classifications.17 139 patients with COPD were enrolled in 22 cohorts of 11 countries; 8823 of them had complete data and were analyzed. Mean age was 63.9 years(SD 9.8); 5 552(62.9%) were male and mean FEV1 was 54.8%(SD 22.3). Compared with 2015, the GOLD 2019 classified the patients in milder degrees of COPD:groups C and D decreased from 13.6% to 5.8% and 40% to 17.8% respectively (p< 0.001). Five-year mortality did not differ between groups B and C in GOLD 2015; in contrast, in GOLD 2019, five-year mortality was greater for group B than C.When analyzing individually the prognostic accuracy of each of the groups, patients classified as group A and B had better sensitivity and positive predictive value with GOLD 2019 classification than GOLD 2015. On the contrary, GOLD 2015 had better sensitivity for group C and D than GOLD 2019. The AUC for 5-year mortality were only 0.67 (95% CI 0.66-0.68) for GOLD 2015 and 0.65 (95% CI 0.63-0.66) for GOLD 2019.GOLD 2019 does not predict mortality better than GOLD 2015 system.