Clinical Differences and Outcomes between Methamphetamine-Associated and Idiopathic Pulmonary Arterial Hypertension in the PHAR.

RATIONALE Single-center studies demonstrated that methamphetamine use is associated with pulmonary arterial hypertension (Meth-APAH). We used the Pulmonary Hypertension Association Registry to evaluate the national distribution of Meth-APAH, and to compare its impact on patient-reported and clinical outcomes relative to idiopathic PAH. OBJECTIVES To determine if patients with Meth-APAH differ from those with idiopathic PAH in demographics, regional distribution in the US, hemodynamics, health-related quality of life, PAH-specific treatment, and health care utilization. METHODS The Pulmonary Hypertension Association Registry is a US-based prospective cohort of patients new to care at a Pulmonary Hypertension Care Center. The registry collects baseline demographics, clinical parameters, and repeated measures of health-related quality of life, World Health Organization functional class, six-minute walk distance, therapy, and health care utilization. Repeated measures of functional class, health-related quality of life, type of therapy, emergency department visits, and hospitalizations were compared using generalized estimating equations. RESULTS Of 541 participants included, 118 had Meth-APAH; 83% of Meth-APAH arose in the Western US. The Meth-APAH group was younger, had a poorer socioeconomic status, and lower cardiac index than the idiopathic PAH group, despite no difference in mean pulmonary artery pressure or pulmonary vascular resistance. The Meth-APAH group had a more advanced functional class in longitudinal models (0.22 points greater, 95%CI: 0.07 to 0.37), and worse PAH-specific (emPHasis-10) health-related quality of life (-5.4, 95%CI: -8.1 to -2.8). There was no difference in dual combination therapy, however, participants with Meth-APAH were less likely to be initiated on triple therapy (OR: 0.43, 95%CI 0.24 to 0.77) or parenteral therapy (OR: 0.10, 95%CI 0.04 to 0.24). Participants with Meth-APAH were more likely to seek care in the emergency department (IRR: 2.30, 95%CI 1.71 to 3.11) and more likely to be hospitalized (IRR: 1.42, 95%CI 1.10 to 1.83). CONCLUSIONS Meth-APAH represents a unique clinical phenotype of PAH, most common in the Western US. It accounts for a notable proportion of PAH in expert centers. Assessment for methamphetamine use is necessary in patients with PAH.