Rationale: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) document has modified the grading system directing pharmacotherapy, but how this relates to the previous one from 2015 and to comorbidities, hospitalizations, and mortality risk is unknown. Objectives: The aim of this study was to evaluate the changes in the GOLD groups from 2015 to 2017 and to assess the impact on severity, comorbidities, and mortality within each group. Methods: We prospectively enrolled and followed, for a mean of 5 years, 819 patients with chronic obstructive pulmonary disease (84% male) in clinics in Spain and the United States. We determined anthropometrics, lung function (FEV1%), dyspnea score (modified Medical Research Council scale), ambulatory and hospital exacerbations, and the body mass index, obstruction, dyspnea, and exercise capacity (BODE) and Charlson indexes. We classified patients by the 2015 and 2017 GOLD ABCD system, and compared the differential realignment of the same patients. We related the effect of the reclassification in BODE and Charlson distribution as well as chronic obstructive pulmonary disease and all-cause mortality between the two classifications. Measurements and Main Results: Compared with 2015, the 2017 grading decreased by half the proportion of patients in groups C and D(20.5% vs. 11.2% and 24.6% vs. 12.9%; P < 0.001). The distribution of Charlson also changed, whereas group D was higher than B in 2015, they become similar in the 2017 system. In 2017, the BODE index and risk of death were higher in B and D than in A and C. The mortality risk was better predicted by the 2015 than the 2017 system. Conclusions: Compared with 2015, the GOLD ABCD 2017 classification significantly shifts patients from grades C and D to categories A and B. The new grading system equalizes the Charlson comorbidity score in all groups and minimizes the differences in BODE between groups B and D, making the risk of death similar between them.