Sildenafil for adult Asian patients with pulmonary arterial hypertension: a systematic review and meta-analysis

Background: The prognosis of patients with untreated pulmonary arterial hypertension (PAH) has historically been poor. Previous studies have recommended that sildenafil was beneficial, but the dose varies greatly. In this study, we aimed to evaluate the safety and effectiveness of sildenafil [dose: 20 mg/three times a day (TID)] for adult Asian PAH patients. Methods: Electronic databases (MEDLINE, Embase, Web of Science, the Cochrane Library, CBM, CNKI, and Wanfang Data) were searched from their inception to January 2022. We recruited all randomized controlled trials and non-randomized studies of interventions that compared sildenafil (20 mg/TID) versus placebo or symptomatic treatment for adult Asian PAH patients. Results: A total of 10 studies involving 480 participants were included. Compared to symptomatic treatment, sildenafil-treated patients were more likely to walk 57.68 meters further in six-minute walk distance [mean difference (MD) =57.68 m, 95% confidence interval (CI): 41.55 to 73.81], achieve an improvement in systemic arterial oxygen saturation (MD =2.48%, 95% CI: 1.26 to 3.71), and increase the score of the Borg scale for dyspnea (MD =-0.99 points, 95% CI: -1.45 to -0.53). The total number of patients with World Health Organization class III and IV also exhibited a downtrend. Compared to the placebo, sildenafil was associated with a reduction in the mean pulmonary artery pressure (MD =-4.13 mmHg, 95% CI: -6.52 to -1.74) and the level of brain natriuretic peptide (MD =-86.16 pg/mL, 95% CI: -103.39 to -68.93). The most common adverse events were headache, flushing, dyspepsia, and diarrhea, which were relatively mild. Discussion: Sildenafil at a close of 20 mg/TID is well tolerated in adult Asian PAH patients, and is associated with statistically significant improvements in exercise capacity, cardio-pulmonary function, and haemodynamic indices. The long-term prognosis still needs to be evaluated and confirmed by further trials.