Goldstein 2003.

Methods	Randomised controlled trial Method of randomisation: random numbers table, block randomisation in groups of 4 Allocation concealment: adequate Outcome assessor blinding: described Withdrawals/Dropouts: fully accounted for
Participants	Screened: 328 Randomised: 55 (LVRS 28, control 27) Completed: 50 (LVRS 24, control 26) Mean age in years: 65 Diagnosis: CT or V/Q scan Emphysema: heterogeneous distribution Entry criteria: < 75 years; FEV1 < 40% predicted; TLC > 120% predicted; evidence of heterogenous emphysema on CT or V/Q scan Exclusion criteria: asthma; prior lung surgery; pleural disease; contraindications for surgery; inability to attend PR or follow‐up; pulmonary hypertension Baseline QoL: not reported (SF‐36 administered to participants, but not reported on) 6‐minute walk in metres (SE): 387 (15) for LVRS vs 372 (17) for control FEV1 in litres (% predicted): 0.8 (33) for LVRS vs 0.7 (32) for control RV in % predicted: 228 for LVRS vs 253 for control TLC in % predicted: 142 for LVRS vs 155 for control PaO2: not stated PaCO2: not stated DLCO: not stated
Interventions	LVRS via video‐assisted thoracic surgery (VATS) (or less often by median sternotomy at the discretion of the surgeon) vs ongoing medical treatment including pulmonary rehabilitation. A short course of pulmonary rehabilitation was offered to participants in the surgery group. Pulmonary rehabilitation: 6‐week programme with supervised physical exercise, educational and psychosocial components Outcomes assessed at 3, 6, 9 and 12 months after randomisation
Outcomes	Quality of life (measured by the CRDQ); 6‐minute walking distance, submaximal cycle endurance time; FEV1; FEV1/FVC; RV; FRC; TLC; mortality
Notes	"This study was supported, in part, by the Physician's Services Incorporated Foundation (Ontario, Canada) and by West Park Healthcare Centre Foundation."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random numbers table, block randomisation in groups of 4
Allocation concealment (selection bias)	Low risk	Study authors reported that allocation was concealed, with the physician and surgeon remaining unaware of the arm to which the participant would be allocated; however, they did not describe methods.
Blinding of participants and personnel (performance bias) All outcomes	High risk	LVRS does not lend itself to blinding.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Research assistants who were blind to the participant's group allocation conducted all outcome assessments at 3, 6, 9 and 12 months after randomisation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing data due to treatment complications displayed graphically; attrition also reported
Selective reporting (reporting bias)	Unclear risk	Protocol was not available for comparison.
Other bias	High risk	Possible selective recruitment, as participants were referred by respiratory physicians, and a physician and a surgeon reassessed those wishing to proceed and made the final decision regarding eligibility; no other information was provided. Furthermore, no sham‐surgery group, which might lead to some placebo effects (as mentioned by study authors)