Goudie 2014.

Methods	Randomised, double‐blind, parallel‐group, placebo‐controlled trial 12 weeks duration
Participants	People with COPD confirmed on respiratory function tests, and associated pulmonary hypertension, confirmed on TTE (WHO Group 3) Inclusion criteria: Men or women, aged between 35 and 85 years inclusive Known diagnosis of COPD A post‐bronchodilator FEV1 < 80% predicted Pulmonary acceleration time < 120 ms or right ventricular systolic pressure > 30 mmHg Exclusion criteria: Pulmonary stenosis Left‐ventricular outflow obstruction confirmed by echocardiography Left‐ventricular systolic dysfunction (< 45%) Taking nitrates, nicorandil, or doxazosin Systolic blood pressure < 90 mmHg, recent stroke, unstable angina, past history of non‐arteritic anterior ischaemic optic neuropathy Baseline characteristics: Mean FEV1 1.06 ± 0.41 L (41% pred.), mPAP 30 ± 7 mmHg (PAT derived), RVSP 42 ± 10 mmHg. n = 120
Interventions	Tadalafil 10 mg daily (N=60) compared to placebo (N=60)
Outcomes	Primary endpoint: 6MWD Secondary endpoints: SGRQ; SF‐36 and Minnesota questionnaires (QOL); BNP DLCO and echo parameters. Inclusion: moderate‐severe COPD and PH (RVSP > 30 mmHg or a pulmonary acceleration time (PAT) < 120 ms, or both)
Notes	Publicly funded Trial was conducted at three centres in Scotland, UK (Dundee, Perth, and Fife), between Sept 1, 2010, and Sept 1, 2012
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Eligible patients were randomly assigned in a 1:1 ratio, via centralised randomisation with a computer‐generated sequence and block sizes of four, to receive daily tadalafil 10 mg or matched placebo, orally"
Allocation concealment (selection bias)	Low risk	Quote: "The intervention and placebo packs were identical in presentation (capsules and bottle) and double blinding was maintained throughout"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Patients, study investigators, outcome assessors, and those administering drugs were masked to group allocation. Unmasking was done only after the end of the trial once all data had been collected and analysed"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Patients, study investigators, outcome assessors, and those administering drugs were masked to group allocation. Unmasking was done only after the end of the trial once all data had been collected and analysed"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	120 patients were randomly assigned to receive tadalafil (n = 60) or placebo (n = 60), of whom 113 (94%) completed the study, reasons not given
Selective reporting (reporting bias)	Low risk	Unlikely selective reporting bias
Other bias	Low risk	Other risk unlikely