Exercise performance after standard rehabilitation in COPD patients with lung hyperinflation. An observational multicentre cohort study.

Background: The role of pulmonary rehabilitation (PR) in COPD patients with lung hyperinflation has not yet been fully investigated. Aim: In three Italian rehabilitation centres we retrospectively evaluated the effect of a standard PR course on exercise tolerance and symptoms according to the presence or absence of associated lung hyperinflation, as defined by lung function parameters. Methods: In a cohort of 823 COPD patients (age 71±8 yrs, FEV1 56±18 % pred.) we have systematically recorded: changes (D) in six minute walking test (6MWD) as the primary outcome; dyspnoea (D); muscle fatigue (F); SO2nadir during effort; perceived breathlessness score (MRC); and specific health related Quality-of-Life (SGRQ). Outcomes were compared between patients with lung hyperinflation (n=283, LH) or without (n=540 No-LH).Results: Groups were comparable for age, body mass index, baseline exercise tolerance, and breathlessness. D-6MWD (+72±47 vs +62±42 m, p<0.05); D-D (- 2.3±1.7 vs -1.9±1.3 point, p<0.05) and D-SO2nadir (+1.4±3.0 and +0.5±3.3 point, p<0.05) were greater in LH than in No-LH. Using a multivariate linear regression model, D-6MWD in the LH group significantly correlated with lower functional residual capacity (p=0.021) and baseline 6MWD (p=0.004).Conclusion: Tolerance, gas exchange and perceived symptoms during effort are the parameters that proved to gain a significant benefit from standard rehabilitation in COPD patients with a lung hyperinflation condition.