Severe COPD patients respond best to pulmonary rehabilitation
MedWire News: Patients with more severe chronic obstructive pulmonary disease (COPD) have a better response to pulmonary rehabilitation than less ill patients, research shows.
Patients with worse lung function combined with worse exercise capacity appeared to benefit the most from the pulmonary rehabilitation program, according to Wytske Altenburg (University of Groningen, the Netherlands) and colleagues.
The new data "provide a strong argument not to exclude these severely disabled patients from pulmonary rehabilitation programs," say the researchers.
Pulmonary rehabilitation is known to improve exercise-induced dyspnea, exercise capacity, and daily physical activity levels in COPD patients.
Still, not all COPD patients benefit equally from rehabilitation programs, state Altenburg and colleagues. For example, exercise as a limiting factor may play a role in the response to pulmonary rehabilitation.
In their study, which is published in Respiratory Medicine, the group attempted to identify patient characteristics that would predict the degree of improvement in endurance exercise capacity following rehabilitation.
In total, 102 patients with COPD were enrolled in a standard pulmonary rehabilitation program that included three sessions per week lasting between 1 and 2 hours.
After 7 weeks, the mean change in the endurance shuttle walk test (ESWT) was 100%, corresponding to an increase of 188 m.
Four baseline measures - percent of predicted forced expiratory volume in 1 second (FEV1), peak power output, change in lactate concentration, and incremental shuttle walk test (ISWT) - were negatively correlated with the change in ESWT.
Individually, patients with lower peak power outputs and ISWT at baseline improved more on the ESWT. In addition, COPD patients with a low FEV1 and a smaller change in lactate concentration also improved on the ESWT.
However, the researchers state that no single variable from lung function or exercise testing at baseline was sufficient to predict the response to exercise training.
Instead, cluster analysis identified two groups of patients with a combination of variables who benefited from the rehabilitation program.
COPD patients with a combination of worse lung function and exercise capacity showed the largest improvement in endurance exercise capacity, while those with a combination of better lung function and exercise capacity "showed a substantially smaller improvement," according to the researchers.
Altenburg and colleagues suspect that patients with the most reduced exercise capacity and lung function experience a downward spiral, one that starts with dyspnea, and leads to avoiding physical activity, deconditioning, and a lack of motivation.
These factors should be investigated as they might be important in future rehabilitation efforts, they state.
By MedWire Reporters