Study designs of evaluations included in the review
Systematic reviews, randomised controlled trials (RCTs) and cluster controlled trials (CCTs) were eligible for inclusion.
Specific interventions included in the review
Studies investigating physical activity, defined as 'general physical condition enhancement', were eligible. The following interventions were utilised in the included studies:
primary care physiotherapist, giving both general and specific muscle training, education and recreation, 3 times weekly for 12 weeks;
home training of large muscle groups at low intensity, 7 times weekly for 12 weeks;
hospital-based general and specific muscle training, twice weekly for 12 weeks;
outpatient clinic together with home-based general and specific muscle training and education, 7 times weekly for 18 months; and
hospital-based general and specific muscle training, education and muscle stretching, twice weekly for 8 weeks.
Participants included in the review
COPD. Studies enrolling patients with mild to moderate COPD were eligible. If the severity was not reported, a forced expiratory volume (FEV1) of 50% lower than predicted was used as the lower threshold for study inclusion. Studies including patients with severe COPD had to report the results separately. Patients classified as having severe COPD were excluded. The mean age of the patients in the included studies ranged from 49 to 63 years.
Outcomes assessed in the review
The main outcomes of interest were exercise tolerance, quality of life, dyspnoea, days of hospitalisations and exacerbations. Studies which did not include at least one of these outcomes were excluded.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review. However, they state that if there was any doubt regarding inclusion, consultation between two reviewers took place until full consensus was reached.