It is with this background that the well-conducted study by Jacobs et al13 in this issue of CHEST (see page 1230) is particular timely and relevant. In this article, the authors investigated the reasons for the worsened prognosis in male patients with PAH. They performed a retrospective review of 101 patients referred with PAH to their single center in VU University Medical Centre Amsterdam. Prior to the initiation of therapy, these patients had undergone right-sided heart catheterization and cardiac MRI, as well as recording and indexing of their baseline clinical characteristics. The median follow-up time was 5.7 years, and the 5-year survival was worse in male patients at 63%, compared with female patients with 85%, consistent with prior studies. Men had shorter 6-min walk distances, worse functional class, and higher brain natriuretic peptide levels at follow-up compared with female patients. Importantly, neither the right heart hemodynamics (pulmonary artery pressures, cardiac output, pulmonary vascular resistance) at baseline nor at follow-up showed significant differences between men and women, demonstrating that men were not sicker at baseline, and neither were they less likely to demonstrate a pulmonary vascular response to vasodilator therapy. The type of therapy and escalation of therapy were also no different between men and women to account for the possible difference.