Jalalian 2015.

Methods	Randomised placebo‐controlled trial 6 weeks duration
Participants	Inclusion criteria: Participants with beta‐thalassaemia intermedia PH based on TTE Exclusion criteria: Participants with hepatic or renal insufficiency Treated with organic nitrates or alpha‐blockers (WHO Group 5) n = 22
Interventions	Tadalafil (40 mg daily) (N=22) or placebo (N=22)
Outcomes	PASP TRV and parameters related to systolic function of the right ventricle including changes in TAPSE, pulsed Doppler peak velocity at the tricuspid annulus (S') were measured by TTE
Notes	Publicly funded Trial conducted at Babol, Northern Iran between December 2013 and April 2014
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "the participants were randomly divided" but methods are not stated
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	Blinding of outcome assessment was not clear
Incomplete outcome data (attrition bias) All outcomes	Low risk	Withdrawals were accounted for, and were even across both groups. Quote: "Three participants in the tadalafil group and one participant in the placebo group withdrew due to side effects"
Selective reporting (reporting bias)	Low risk	Prespecified outcomes were reported
Other bias	Low risk	Other bias is unlikely