Twenty-six RCTs (n=3,519) were included. Sample sizes ranged from 16 to 470 participants.
Exercise capacity: All treatments produced a statistically significant increase compared with placebo or control. Epoprostenol and prostacyclin analogues had a WMD of 35.4m (95% CI 17.3 to 53.5; nine trials), endothelin receptor antagonists a WMD of 46.1m (95% CI 38.1 to 54.2; eight trials) and phosphodiesterase-type-5 inhibitors a WMD of 33.8m (95% CI 24.8 to 42.7; six trials). There was significant heterogeneity for the epoprostenol and prostacyclin analogues analysis (but not for other analyses). Pooled WMD for all three drug types was 38.5m (95% CI 29.9 to 47.2; 23 trials). Subgroup analyses showed no differences in effect size.
Mortality: None of the individual drug types showed a statistically significant reduction in mortality, but pooling all three types produced a significant result (RR 0.61, 95% CI 0.38 to 0.98; 23 trials) that represented a reduction in all-cause mortality of 39% (95% CI 2% to 62%). A reduction in mortality was seen in trials that included patients who were functional class IV (RR 0.58 95% CI 0.35 to 0.96; 16 trials), but not in trials that excluded these patients. There was no significant statistical heterogeneity.
Haemodynamics: All three types of treatment showed a significant improvement in pulmonary vascular resistance and pulmonary artery pressure (result details were provided), but this represented only a 6% decrease from baseline.
The was no evidence of publication bias. Further results were reported.