Abe Y, Suzuki M, Makita H, et al. - Researchers sought to determine the links between 1-year clinically important deterioration (CID) and the following long-term clinical results among Japanese patients suffering from chronic obstructive pulmonary disease (COPD) who have been noted to have different characteristics relative to the Westerners. Experts applied 2 definitions of CID. Definition 1 consisted of  ≥ 100 mL reduction in forced expiratory volume in 1 s (FEV ₁ ), ≥ 4-unit increment in St George’s Respiratory Questionnaire (SGRQ) score from baseline, or moderate or severe exacerbation. They doubled the thresholds for the FEV ₁ and SGRQ score components for Definition 2. A significantly worse mortality was observed in patients with CID using Definition 1, but not any single CID component, during the first year when compared with those without CID. A similar trend on mortality was exhibited by patients with CID using Definition 2, and they experienced a shorter exacerbation-free survival vs those without CID. Thus, evaluating long-term disease progression and clinical outcomes via CID was concluded as a beneficial as well as useful way for even Japanese population with COPD. Optimization of CID definition based on features of COPD population and the observation period for CID, might be done.