Methamphetamine-associated PAH a ‘distinct clinical phenotype’

A new study highlights the clinical differences and outcomes of methamphetamine-associated pulmonary artery hypertension compared with idiopathic PAH, including less favorable hemodynamics and regional variation.

“In a prospective, multicenter, U.S.-based registry of patients with PAH, we found that [methamphetamine-associated PAH] represents a distinct clinical phenotype when compared with idiopathic PAH,” Nicholas A. Kolaitis, MD, assistant professor of medicine at the University of California, San Francisco, School of Medicine, and colleagues wrote in the Annals of the American Thoracic Society.

Researchers evaluated baseline demographics, clinical parameters, repeated health-related quality of life measures, WHO functional class, 6-minute walk distance, therapy and health care use from 541 participants in the Pulmonary Hypertension Association Registry prospective cohort. Participants had diagnosed PAH and were new to care at a pulmonary hypertension care center.

In the cohort, 118 participants had methamphetamine-associated PAH (37% men) and 423 had idiopathic PAH (24% men). Participants with methamphetamine-associated PAH were younger (mean age, 47.5 years vs. 55.5 years), with poorer socioeconomic status and lower cardiac index compared with participants with idiopathic PAH (P < .03 for all). There was no difference in mean pulmonary artery pressure or pulmonary vascular resistance between both groups.

Researchers observed a more advanced WHO functional class (P = .032) and worse PAH-specific health-related quality of life (P < .001) among participants with methamphetamine-associated PAH in longitudinal models. Those with methamphetamine-associated PAH were also less likely to be initiated on triple therapy (OR = 0.43; 95% CI, 0.24-0.77) or parenteral therapy (OR = 0.1; 95% CI, 0.04-0.24). There was no difference in dual combination therapy between the groups.

Participants with methamphetamine-associated PAH were also more likely to seek ED care (incidence rate ratio [IRR] = 2.3; 95% CI, 1.71-3.11; P < .001) and were more likely to be hospitalized (IRR = 1.42; 95% CI, 1.10-1.83; P = .007) compared with participants with idiopathic PAH.

According to the researchers, the diagnosis of pulmonary vascular disease due to methamphetamine use suggests a regional phenomenon, as most diagnoses (83%) occurred in centers located in the western United States. Kolaitis and colleagues noted that “[t]his is the first time that regional variation of [methamphetamine-associated PAH has been shown” and that “[t]his finding parallels the U.S. patterns of drug use,” in particular methamphetamine use.

“Given the increasing use of methamphetamine across the United States and the world, we expect methamphetamine-associated PAH to become an important clinical entity in PAH,” the researchers wrote. “Providers should be aware of this high-risk patient population given the less favorable hemodynamics and the increased health care use.”