Although AECOPDs are associated with impairments of muscle function, walking ability and HRQL, no reports to date have included baseline pre-AECOPD measurements to allow comparison to measurements performed when subjects were stable. Therefore, we enrolled patients post-PR in order to capture outcome measures at the time of program completion and to use these as baseline measures for those patients experiencing an AE-COPD. In order to ensure that these baseline measures remained current, we repeated them at intervals of 3 months or until an AECOPD occurred. These baseline measures did not vary with time, reflecting the clinical stability of this population of patients with COPD, in the absence of an AECOPD.
We observed differences in the 6MWT distances walked at baseline between those who subsequently experienced an AECOPD and those who did not (mean 6MWT distance walked in those who experienced a severe event, 335}± 101 m; mean 6MWT distance walked in those who experienced a moderate event, 354 ± 95 m; mean 6MWT distance walked in those who experienced no event, 416 ± 95 m), as well as differences in the LCADL, a selfreport of breathlessness with activities, and in the FT, a measure of health utility. These observations are in keeping with the findings of Garcia-Aymerich and colleagues and Kessler and colleagues, highlighting the association between exercise capacity and the occurrence of an AECOPD. We did not find any differences in lung mechanics, exercise capacity, or HRQL between those patients who experienced moderate AECOPDs and those who experienced severe AECOPDs. The sample size was too small to evaluate the influence of gender on these results.