Conference: 2008 International PHA Conference and Scientific Sessions
Release Date: 06.20.2008
Presentation Type: Abstracts
Maradit-Kremers H., Golbin J.M., Slusser J.P., Scott C.G., Kane G.C., McGoon M.D.
Mayo Clinic, Rochester, MN, USA
BACKGROUND: PAH is a rare, progressive disease characterized by an increase in pulmonary-vascular resistance, leading to right-ventricular failure and death. The natural history of PAH is heterogeneous. Recent medical advances have led to introduction of new therapies, but relatively little is known of the factors associated with the intensity and choice of drug therapy and their impact on survival. The purpose of this study was to examine trends in therapeutic strategies and predictors of survival in PAH.
METHODS: This retrospective cohort study included all PAH patients treated at a large referral center in the US between 1/1/199512/31/2004. The medical records of each patient were reviewed to collect data on clinical and hemodynamic characteristics (echocardiography, right heart catheterization, pulmonary function). Disease etiology was classified according to WHO classification and included idiopathic PAH (IPAH) and PAH associated with connective tissue diseases (PAHc). Drug exposure data were collected on all courses of calcium channel blockers, prostanoids, endothelin receptor antagonists and PDE-5 inhibitors, as well as other concomitant therapies. Predictors of initiation of individual drugs and clinical and treatment specific predictors of mortality were assessed using Cox models.
RESULTS: The study cohort included 657 patients with a mean age of 53.6 (±15.9) years and 77% were female. Mean disease duration was 2.4 (±2.7) years. 366 (55.7%) patients had IPAH and 154 (23.4%) patients had cPAH with median survival 3.8 and 2.8 years, respectively. PAH treatment included calcium channel blockers in 409 (62%) patients, prostanoids in 267 (41%), endothelin receptor antagonists in 174 (26%) and PDE-5 inhibitors in 109 (17%) patients. 41% of patients received more than one drug therapy. Time to initiation of drug therapy did not change significantly since 1995 and 40% of patients were treated within the first year of diagnosis (Figure). After 2002, at least half of the treated patients received endothelin receptor antagonists or PDE-5 inhibitors. Patients with functional class III/IV were significantly more likely to receive prostanoids (HR 2.28, 95% CI 1.72, 3.03), endothelin receptor antagonists (HR 1.41, 95% CI 1.03, 1.94) and PDE-5 inhibitors (HR 1.54, 95% CI 1.03, 2.31). Similarly, higher RA and PA pressures were associated with the initiation of these drugs, indicating strong confounding by severity for examining effectiveness of these drugs on survival.
CONCLUSIONS: In this large contemporary cohort of patients with PAH, treatment patterns changed over time, with a significant increase in use of newer drugs in recent years.
Funding for this study was provided by Pfizer