Guell 2017.

Study characteristics
Methods	RCT, parallel group. Setting: Spain. Study duration: 36 months
Participants	138 participants Intervention: n = 68, Control: n = 50 Age, mean and SD: Intervention: 64 ± 9, Control: 64 ± 8 FEV1% predicted, mean and SD: Intervention: 36 ± 10, Control: 37 ± 11. Inclusion criteria: Diagnosis of COPD, according to the GOLD guidelines with spirometric grade II ‐ IV severity, between 18 and 75 years old ; ex‐smokers or with intention to quit; BODE index value between 3‐10, and no acute exacerbation during the last four weeks prior to enrolment. Exclusion criteria: COPD participants showing a bronchodilator response (FEV1 increment > 15% of the baseline value after 200 μg of inhaled bronchodilator), a clinical diagnosis of respiratory disease other than COPD, severe coronary artery disease, orthopedic diseases seriously limiting mobility, life expectancy lower than 2 years, or inability to co‐operate.
Interventions	Intervention group: Components: exercise (weight and cycle ergometre). This group was asked to continue at home with a programme similar to that conducted at the hospital. Supervision: the physiotherapist called the IG participants every 15 days, and participants attended the hospital for a training session, every 15 days alternatively (the participants had weekly contact with either a phone call or a hospital visit). On the alternate week, the participant attended the hospital for a supervised training session. The participant never increased the load of any of the exercises at home without supervision by the physiotherapist. The cycle ergometres were provided by the team. Control group: usual care and counselling on physical activity without supervision.
Outcomes	Exercise capacity: 6MWD, HRQoL: SF‐36 (domains) CRQ (domains), BODE and mortality.
Notes	No study sponsor. Trial is registered at NCT 01090999
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was achieved using a computer programme by an independent statistician. The process was stratified in a 1:1 allocation with permuted blocks of varying size.
Allocation concealment (selection bias)	Unclear risk	Insufficient information. Method of concealment not described.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Reported as open‐label on trials registry, and it is not possible to blind participants to intervention.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessors were blind to allocation group at baseline and follow up time points
Incomplete outcome data (attrition bias) All outcomes	High risk	Higher attrition rate in the control group (30%) compared to the intervention group (24%).
Selective reporting (reporting bias)	High risk	Outcomes in the manuscript are different from those described in the Clinical trial registration. Clinical trial: dyspnoea (CRQ), 6MWT, BODE index, economical: direct costs (program), indirect costs (exacerbations/admissions), comparison of GR1 and GR2 costs. For all, time frame 1.5 yrs. Paper: Time frame: 12 mo, 24 mo, and 36 mo. Missing outcomes: economical: direct costs (program), indirect costs (exacerbations/admissions), comparison of GR1 and GR2 costs. New outcomes: SF36f, SF36m, CRQ (fatigue, emotional factor, mastery). One of the reasons to consider high risk is "One or more reported primary outcomes were not pre‐specified".
Other bias	Unclear risk	Any self‐reported outcomes are likely to be affected any bias.