TY - JOUR T1 - Room for methodological improvement in gait speed study for COPD patients JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.01445-2021 VL - 58 IS - 6 SP - 2101445 AU - Naoto Kuroda AU - Akihiro Shiroshita AU - Yasushi Tsujimoto Y1 - 2021/12/01 UR - http://erj.ersjournals.com/content/58/6/2101445.abstract N2 - We read with great interest the article by Walsh et al. [1], who investigated whether slower gait speed is an independent risk factor for readmission and mortality in patients hospitalised with COPD exacerbation. This study included 213 patients hospitalised with COPD exacerbation. The Cox proportional hazards model and the Fine and Grey model revealed that 4-m gait speed (4MGS) within 24 h before hospital discharge was associated with both readmission and mortality within 12 months. Considering that 4MGS is a simple and potentially ameliorable measurement, 4MGS could be an important predictor; however, there are some concerns regarding the methodology of this study.Regarding the gait speed study for COPD patients reported by J.A. Walsh and co-workers, there are 3 concerns: 1) lack of internal validation; 2) methodology of comparing model performance; and 3) a way of handling competing risks in the Fine and Gray model https://bit.ly/3g6I8BNWe would like to thank Editage (http://www.editage.jp) for English language editing. ER -