Pulmonary hypertension (PH) is a pathophysiological disorder that may involve multiple clinical conditions and is associated with significant morbidity and mortality. Among PH, pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are rare and life-threatening diseases evolving to right ventricular failure and death in absence of treatment. Development of PAH specific therapies contributed to improve prognosis of patients. Medication adherence (MA) of PH patients is poorly described while it is well recognized that high levels of MA are correlated to better clinical and economical outcomes in cardiovascular diseases.

In this systematic review and meta-analysis, we analyzed the degree of MA to PAH specific therapies in patients with PAH or CTEPH. MA was assessed by medication possession ratio (MPR), proportion of days covered (PDC) and self-reported medication questionnaire. We also analyzed related factors to MA and clinical outcomes according to MA degree.

Twenty studies including 22,673 patients were selected. The median age was 58years and 66% were women. Only one study compared MA between PAH and CTEPH and no study assessed MA for non-specific therapies. Overall pooled mean proportion value of MA to PAH specific therapies was 82% (95% CI: 75%–89%) and values of PDC and MPR were respectively 77% (95% CI: 65%–89%) and 87% (95% CI: 77%–96%) (Fig. 1). Overall pooled proportion of patients with high MA was 66% (95% CI: 56%–75%) with MPR, PDC and Questionary values of 67% (95% CI: 56%–75%), 64% (95% CI: 46%–78%) and 69% (95% CI: 48%–84%), respectively. Most common determinants of non-adherence were combination therapy, sildenafil prescription, increased therapy frequency, increase time since diagnosis, younger age and co-payment/no financial assistance. High degree of MA was also associated with a decrease in hospitalization rate, inpatient hospital stays and outpatient visits. In addition, healthcare costs were higher in patients with low degree of MA.

MA seems to be acceptable in most patients managed for PAH or CTEPH, with around two-thirds of them having high MA to specific PAH therapies. However low MA is associated with poorer outcomes. Identification of related factors to MA could contribute to strengthen therapeutic education in patients at high risk of low MA.