Salem 2013.

Methods	Randomised, placebo‐controlled trial 6 weeks duration
Participants	Inclusion criteria: Adults with symptomatic secondary PH with NYHA functional class The underlying aetiologies of PH were: dilated cardiomyopathy, COPD, chronic thromboembolic disease, ILD, and valvular heart disease (mitral and aortic regurgitation) Exclusion criteria: Primary pulmonary hypertension Hypotension Allergy to sildenafil IHD (WHO Group 2 ‐ 5) n = 40
Interventions	Oral sildenafil (N=20) or matched placebo (N=20) was given in a titrated dose, starting with 25 mg 3 times daily for 1 week, then the dose was doubled to 50 mg 3 times daily according to side effects and tolerability until 6‐week period
Outcomes	Improvement in NYHA functional class PASP LVEF
Notes	Funding source not stated Location of trial and dates of recruitment not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomised using simple randomisation (1:1) to either sildenafil therapy in a titrating dose or placebo
Allocation concealment (selection bias)	Low risk	Placebo‐controlled
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo‐controlled
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	It was unclear if the outcome assessors were blinded to the intervention
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	It was not explicitly stated if all randomised participants completed the trial; no withdrawals were reported
Selective reporting (reporting bias)	Low risk	Prespecified outcomes were reported
Other bias	Low risk	Other risk of bias is unlikely