Abstract: In patients with pulmonary arterial hypertension (PAH), the use of disease-specific therapies (i.e., endothelin
receptor antagonists, phosphodiesterase type-5 inhibitors, soluble guanylate cyclase stimulators, prostacyclins, and prostanoids)
has been associated with disease improvement and decreased mortality risk. We aimed to quantify the adherence
and discontinuation rates for patients prescribed PAH-specific therapies.
Methods We performed a systematic review via searching MEDLINE, EMBASE, and the Cochrane Library from their inception
to 4 March 2022 for observational studies published in English that reported data on adherence to and persistence with
PAH-targeted therapies. Random-effects meta-analysis was performed to explore average adherence and discontinuation rates.
Results In all, 14 studies involving 14,861 individuals prescribed PAH-targeted therapies were included.
The overall pooled proportion of patients adherent to their PAH-targeted medications was 60.9% (95% confidence interval
[CI] 52.3–69.1%). The pooled proportions of patients adherent in questionnaire-based studies and in studies using prescription/
dispensing data were 52.9% (95% CI 48.9–56.9%) and 62.9% (95% CI 53.1–72.2%), respectively. The pooled proportion
of patients who discontinued their PAH-targeted medications was 42.3% (95% CI 31.6–53.3). Factors reported to impact
adherence included administration frequency, length of time on treatment, co-payment, and occurrence of adverse events.
Conclusions In the real world, a considerable proportion of patients prescribed PAH-specific therapies were non-adherent
or discontinued. As diverse factors may influence treatment adherence, multifaceted interventions are needed to address this
trend in order to improve patient outcomes.