Nonadherence to PAH medications compromises outcomes

Patients with pulmonary arterial hypertension (PAH) who do not adhere to medications appear to have poor clinical outcomes, according to a study.

Researchers used claims data from the Komodo Research Database. They identified patients who initiated therapy with phosphodiesterase type 5 inhibitors (PDE5i), endothelin receptor antagonists (ERA), soluble guanylate cyclase (sGC) stimulators, or prostacyclin pathway agents (PPA).

Treatment adherence was assessed as proportion of days covered (PDC) during the treatment period (ie, 60 days after first therapy until treatment discontinuation/censor), with nonadherence defined as PDC <80 percent. Clinical outcomes were evaluated during the treatment period.

A total of 7,496 patients were included in the analysis. Of these, 56.6 percent used a PDE5i, 25.9 percent used an ERA, 6.6 percent used a PPA injectable, 4.7 used inhaled PPA, 3.3 percent used oral PPA, and 2.9 percent used sGC stimulators.

Mean PDC was more than 90 percent across all treatment groups. Nonadherence was highest in the PDE5i (17 percent) and inhaled PPA (15.3 percent) groups. Factors associated with nonadherence differed by drug class.

In stepwise Cox proportional-hazard models, nonadherence was significantly associated with worse clinical outcomes. Compared with adherence, nonadherence increased the risk of mortality by more than twofold in the PDE5i group (hazard ratio [HR], 2.33, 95 percent confidence interval [CI], 1.79–3.03; p<0.001) and by more than fivefold in the ERA group (HR, 5.43, 95 percent CI, 3.33–8.85; p<0.001).