PT  - JOURNAL ARTICLE
AU  - Misu, Shogo
AU  - Kaneko, Masahiro
AU  - Sakai, Hideki
AU  - Oki, Yutaro
AU  - Fujimoto, Yukari
AU  - Ishikawa, Akira
AU  - Ono, Rei
TI  - Exercise-Induced Oxygen Desaturation as a Predictive Factor for Longitudinal Decline in 6-Minute Walk Distance in Subjects With COPD
AID  - 10.4187/respcare.06169
DP  - 2019 Feb 01
TA  - Respiratory Care
PG  - 145--152
VI  - 64
IP  - 2
4099  - http://rc.rcjournal.com/content/64/2/145.short
4100  - http://rc.rcjournal.com/content/64/2/145.full
AB  - BACKGROUND: There are limited longitudinal studies reporting predictive factors for decline in 6-min walk distance (6MWD) in patients with COPD. While previous studies have confirmed the association between air-flow limitation and decline in 6MWD, other factors have not been clarified. The objective of this study was to investigate whether exercise-induced oxygen desaturation (EID) could be a predictive factor for decline in 6MWD in patients with COPD. The interactive effect of air-flow limitation on the association between EID and decline in 6MWD was also investigated.METHODS: A longitudinal observational study was conducted with 71 out-patients with COPD who were followed for 1 year. 6MWD, EID, spirometry, and clinical characteristics were assessed. The effect of EID on changes in 6MWD was examined using linear regression analyses. Furthermore, the subjects were categorized into 4 groups according to their EID and air-flow limitation status, and changes in 6MWD were compared among the groups.RESULTS: 51 subjects completed the follow-up assessments, and 29 (56.9%) experienced EID. Multiple linear regression model revealed that EID was the only predictive factor for changes in 6MWD after adjusting for confounders (β = −38.9, P = .02). As results of multiple comparisons among the 4 groups based on EID and air-flow limitation status, changes in 6MWD in the EID and severe air-flow limitation group were the lowest.CONCLUSION: Our results revealed that EID was a predictive factor for decline in the functional capacity of subjects with COPD. The assessment of EID and air-flow limitation would thus be useful in estimating the prognosis of decline in the functional capacity of patients with COPD.