Exercise performance after standard rehabilitation in COPD patients with lung hyperinflation

The role of pulmonary rehabilitation (PR) in COPD patients with lung hyperinflation has not yet been fully investigated. 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 in three Italian rehabilitation centres. In a cohort of 823 COPD patients (age 71 ± 8 years, FEV₁ 56 ± 18% pred.) we have systematically recorded: changes (∆) in 6-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). Groups were comparable for age, body mass index, baseline exercise tolerance, and breathlessness. ∆-6MWD (+72 ± 47 vs. +62 ± 42 m, p < 0.05); ∆-D (−2.3 ± 1.7 vs. −1.9 ± 1.3 point, p < 0.05) and ∆-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, ∆-6MWD in the LH group significantly correlated with lower functional residual capacity (p = 0.021) and baseline 6MWD (p = 0.004). Tolerance, gas exchange and perceived symptoms during effort are the parameters that gain a significant benefit from standard rehabilitation in COPD patients with a lung hyperinflation condition.