CLVR 2005.

Methods	Randomised clinical trial Method of randomisation: not described Allocation concealment: conducted off‐site at a data co‐ordinating centre Outcome assessor blinding: described Withdrawals/Dropouts: fully accounted for
Participants	Screened: 467 Randomised: 62 (LVRS 32; control 30) Completed: 59 (LVRS 29; control 30) Mean age in years: 63.6 Diagnosis: CT and VP scan Emphysema: heterogeneous and homogenous Diseases included: not stated Entry criteria: advanced emphysema, CRQ < 4, < 80 years, 15% to 40 FEV1 % predicted, FEV1 response to bronchodilator < 30% predicted and 300 mL, TLC and RV > 120% predicted, RV > 200% predicted, RV/TLC ratio % predicted 60%, PaCO2 < 55 mmHg, 17 to 32 BMI, compliance with rehabilitation Exclusion criteria: mechanical ventilation, antitrypsin deficiency, bullous emphysema, bronchiectasis, obliterated pleural space, pulmonary node, prednisolone > 10 mg, hypertension > 30 mmHg, life expectancy < 1 year, registered for lung transplant Baseline SF‐36 utility score (SD): 0.648 (0.110) for LVRS vs 0.622 (0.128) for control * CRQ: 3.42 (0.98) for LVRS vs 3.37 (0.79) for control * 6‐minute walk, metres: 340 for LVRS vs 319 for control FEV1 in litres (% predicted): 0.73 (25) for LVRS vs 0.65 (23) for control RV in litres: 5.4 for LVRS vs 5.37 for control TLC in litres (% predicted): 8.2 (136) for LVRS vs 7.78 (138) for control PaO2 in mmHg: 687.38 for LVRS vs 65.93 for control * PaCO2 in mmHg: 45.93 for LVRS vs 45.46 for control * DLCO in mL/min/mmHg (% predicted): 8.18 (31) for LVRS vs 8.92 (35) for control * Conditional data obtained from Miller 2005 paper. Final values for complete cohort in CLVR study not reported
Interventions	LVRS via median sternotomy vs usual medical care Optimal care standardised (including PR, bronchodilators, vaccination, steroids and antibiotics) Pulmonary rehabilitation: 6 week course before randomisation (and continued for the duration of the study in both groups) Participants followed up for 2 years post randomisation
Outcomes	Difference QALYs by HUI, morbidity; lung function; quality of life (SF‐36, CRDQ); 6MWD
Notes	"The Canadian Institute of Health Research (CIHR), MT‐14386, funded the Canadian Lung Volume Reduction Surgery Study trial."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Surgeon stratification and blocking were performed at each centre (2 to 4 group blocks).
Allocation concealment (selection bias)	Unclear risk	Study authors reported that allocation was concealed, as it was performed at the data co‐ordinating centre, but 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	Study authors reported, “Every effort was made to blind those persons who were administering outcome measures tests to the allocation group of the study participants. However, as in all surgical clinical trials, blinding was difficult to ensure in all instances.” Furthermore, they added, “A trained individual who was blinded to the patient treatment allocation administered all measurement.”
Incomplete outcome data (attrition bias) All outcomes	Low risk	Study authors reported attrition and percentages of participants with missing outcome data for SF‐36 and 6MWD.
Selective reporting (reporting bias)	Low risk	Prespecified protocol was not available for comparison, but pilot study was published.
Other bias	Low risk	Low ‐ No other bias was detected.