Clarenbach 2015.

Methods	Randomised controlled trial Method of randomisation: not described Allocation concealment: performed via opaque envelopes Outcome assessor blinding: not described Withdrawals/Dropouts: fully accounted for
Participants	Screened: 40 Randomised: 30 Completed: 27 (LVRS 14; control 13) Mean age in years: 63 Diagnosis: CT scan Emphysema: heterogeneous and homogenous Diseases included: not stated Entry criteria (similar to NETT): FEV1 ≤ 45% predicted (≥ 15% predicted among participants ≥ 70 years of age); TLC ≥ 100% predicted; RV ≥ 150% predicted; partial pressure of resting arterial carbon dioxide ≤ 60 mmHg; resting partial pressure of arterial oxygen ≥ 45 mm Hg; ability to walk ≥ 140 metres (m) in 6 minutes; ability to complete 3 minutes on bicycle ergometer; abstinence from smoking for 6 months before randomisation Exclusion criteria: concurrent medical conditions precluding surgery or that might interrupt follow‐up Baseline QoL: not stated 6‐minute walk, metres: 326 for LVRS vs 287 for control FEV1 in % predicted (SD): 27.8 (7.2) for LVRS vs 26.2 (5.9) for control RV: not stated TLC in % predicted (SD): 124.5 (9.1) for LVRS vs 137.2 (19.8) for control PaO2: not stated PaCO2: not stated DLCO median % predicted (IQR): 35 (27 to 39) for LVRS vs 33 (31 to 38) for control
Interventions	CT scan and perfusion scintigraphy were used to determine the target area, after which surgery was conducted via VATS. For participants with homogenous emphysema, LVRS was performed in the upper lobes.
Outcomes	‐ Assessment of endothelial function by FMD ‐ Determination of systemic inflammation ‐ Blood pressure and heart rate ‐ Daily physical activity and physical activity level ‐ Exercise capacity ‐ Lung function values including FEV1, FVC, RV, DLCO % predicted
Notes	Support was received from "Lunge Zurich."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation was mentioned, but methods were not described.
Allocation concealment (selection bias)	Low risk	"Allocation concealment was performed by the use of sealed envelopes."
Blinding of participants and personnel (performance bias) All outcomes	High risk	LVRS does not permit blinding.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"All measurements were analyzed by one examiner, who was blinded to the randomization protocol (M.K.)."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition was reported.
Selective reporting (reporting bias)	Unclear risk	No protocol was published, but trial was registered at Clinicaltrials.gov: NCT 01020344. Data analysis was performed on a per‐protocol basis.
Other bias	Low risk	No evidence of contamination was found other than that reported above, but post hoc analysis was performed to adjust for imbalance in baseline characteristics.