Table 1. Characteristics of included studies.

PDE5: phosphodiesterase-5 (PDE5) inhibitors; COPD: chronic obstructive pulmonary disease, HFpEF: heart failure with preserved ejection fraction.

Author Name	Year	Setting	Population	Groups	Sample size	Type of PDE5	Follow-up
Albini et al. [11]	2017	Single center	Patients with pulmonary arterial hypertension	PDE5	6	Tadalafil	Six months
				Placebo	5
Belyavsky et al. [12]	2020	Single center	Patients with heart failure with preserved ejection fraction and combined pre- and post-capillary pulmonary hypertension	PDE5	30	Sildenafil	Six months
				Placebo	20
Bermejo et al. [13]	2018	Multicenter	Patients with valvular heart disease and persistent pulmonary hypertension	PDE5	104	Sildenafil	Six months
				Placebo	96
Galie et al. [14]	2005	Multicenter	Patients with pulmonary arterial hypertension	PDE5	70	Sildenafil	Three months
				Placebo	65
Galie et al. [15]	2009	Single center	Patients with pulmonary arterial hypertension	PDE5	323	Tadalafil	Four months
				Placebo	82
Guazzi et al. [16]	2010	Single center	Patients with HFpEF and pulmonary hypertension	PDE5	22	Sildenafil	Twelve months
				Placebo	22
Hoendirmis et al. [17]	2015	Single center	Patients with HFpEF and pulmonary hypertension	PDE5	21	Sildenafil	Three months
				Placebo	22
Jing et al. [18]	2011	Single center	Patients with pulmonary arterial hypertension	PDE5	42	Vardenafil	Three months
				Placebo	16
Lewis et al. [19]	2007	Single center	Patients with systolic heart failure and secondary pulmonary hypertension	PDE5	17	Sildenafil	Three months
				Placebo	17
Palazzini et al. [20]	2010	Single center	Patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension	PDE5	56	Sildenafil	Four months
				Placebo	50
Rao et al. [21]	2011	Single center	Patients with pulmonary arterial hypertension and COPD	PDE5	15	Sildenafil	Three months
				Placebo	18
Simonneau et al. [22]	2008	Multicenter	Patients with pulmonary arterial hypertension	PDE5	133	Sildenafil	Four months
				Placebo	134
Suntharalingam et al. [23]	2008	Single center	Patients with chronic thromboembolic pulmonary hypertension	PDE5	9	Sildenafil	Three months
				Placebo	10
Vitulo et al. [24]	2016	Multicenter	Patients with pulmonary arterial hypertension and COPD	PDE5	10	Sildenafil	Four months
				Placebo	18
Vizza et al. [25]	2017	Multicenter	Patients with pulmonary arterial hypertension	PDE5	50	Sildenafil	Three months
				Placebo	53
Wilkins et al. [26]	2005	Single center	Patients with pulmonary arterial hypertension	PDE5	13	Sildenafil	Four months
				Placebo	12
Zhuang et al. [8]	2014	Single center	Patients with pulmonary arterial hypertension	PDE5	60	Tadalafil	Four months
				Placebo	64