Table 1 All possible GOLD severity stage (2014) changes between visits
From: The effect of changes to GOLD severity stage on long term morbidity and mortality in COPD
A → A | B → A | C → A | D → A |
A → B | B → B | C → B | D → B |
A → C | B → C | C → C | D → C |
A → D | B → D | C → D | D → D |