Donohue 2015b.

Methods	Design: randomised, double‐blind, parallel‐group, double‐dummy, placebo‐controlled trial. Countries: 7 countries (US and European countries and Russia). Site: 71 centres. Study duration: 12 weeks. Study start: June 2013. Run‐in period: 7 to 14 days.
Participants	Key inclusion criteria: %pred FEV1 30% to 70%, mMRC ≥ 2, no recent exacerbation. Numbers of randomised and completed cases: 700 and 638. Age: 63.6 (SD 8.9) years. Male/female: 528/169. %pred FEV1: 49.5% (SD 10.9).
Interventions	LAMA/LABA: umeclidinium/vilanterol (62.5/25 μg). LABA/ICS: salmeterol/fluticasone (50/250 μg) twice daily.
Outcomes	Primary endpoint: Change from baseline in 24‐h weighted‐mean serial FEV1 on treatment day 84. Umeclidinium/vilanterol (62.5/25 μg): 0.213 (SE 0.0137). Salmeterol/fluticasone (50/250 μg) twice daily: 0.112 (SE 0.0139).
Notes	Registration: NCT01879410, GSK‐DB2114951. COI: sponsored by GlaxoSmithKline.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Central randomisation schedule was generated using a validated computer system (RanAll, GSK).
Allocation concealment (selection bias)	Low risk	Centralised randomisation prevented the foreknowledge of intervention assignments by neither researchers nor participants.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Study was double‐blinded. Performance bias was not suspected.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Study was double‐blinded. Detection bias was not suspected.
Incomplete outcome data (attrition bias) All outcomes	Low risk	638/700 participants completed the study. Considerable attrition bias was not suspected because attrition was < 20%. Attrition was 6.9% in umeclidinium/vilanterol arm and 10.9% in salmeterol/fluticasone arm.
Selective reporting (reporting bias)	Low risk	Study was registered and the prespecified outcomes were appropriately described.
Other bias	High risk	COI: sponsored by GlaxoSmithKline.