Six-Minute Walk Distance in Patients With Severe End-Stage COPD

In Brief PURPOSE To evaluate the relationship between the 6-minute walk distance (6MWD) and survival in a cohort of patients with severe end-stage chronic obstructive pulmonary disease (COPD) who received inpatient pulmonary rehabilitation (IPR) from 1995 to 2007. METHODS We retrospectively analyzed 815 patients with severe end-stage COPD who received IPR. 6MWDs before and after IPR (pre-6MWD, post-6MWD) were compared to assess whether 6MWD was significantly changed after IPR. The Kaplan-Meier survival curves were constructed to show the relationship between survival and 6MWD. The age- and or comorbidities-adjusted Cox proportional hazard model was applied to assess association between the survival and the pre-6MWD, post-6MWD, or difference in 6MWD from the pre-6MWD to post-6MWD (Δ6MWD). RESULTS Baseline demographics demonstrated a median age 74.0 years, mostly women (60.1%), and white (89.9%) patients with significant comorbid diseases who were most recently hospitalized in acute care facilities (95.1%). IPR significantly increased the 6MWD (mean distance change: 86.4 m; 95% confidence interval [CI], 81.5–91.3 m). Pre-6MWD was not significantly associated with survival. However, post-6MWD was significantly associated with age- and comorbidity-adjusted survival (post-6MWD hazard ratio = 1.336; 95% CI, 1.232–1.449 [post-6MWD x m relative to post-6MWD 2x m]), and Δ6MWD was also significantly associated with age-, comorbidities-, and pre–6MWD-adjusted survival (Δ6MWD hazard ratio = 1.337; 95% CI, 1.227–1.457 [Δ6MWD x m relative to Δ6MWD 2x m]). CONCLUSIONS In patients with severe end-stage COPD, IPR significantly improved 6MWD, and the post-6MWD and Δ6MWD were positively associated with the length of survival. The relationship between 6-minute walk distance (6MWD) and survival was evaluated in 815 patients with severe end-stage COPD who received inpatient pulmonary rehabilitation (IPR). IPR significantly increased the 6MWD. 6MWD after IPR (hazard ratio = 1.336) and the magnitude of 6MWD difference after IPR (hazard ratio = 1.457) were significantly associated with survival.