Adherence to the evidence-based heart failure drug treatment: Are there sex-specific differences among new users?

The evidence-based heart failure (HF) drug treatment is made of a β-blocker and an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, or hydralazine + isosorbide dinitrate. Little is known about sex-based difference in adherence to the evidence-based HF drug treatment. To assess among new users of the evidence-based HF drug treatment, the association between sex and 1) persistence with the treatment 1 year after its initiation, 2) implementation of the treatment among those who persisted, and 3) overall adherence to treatment in the year following its initiation. Methods: A cohort study was conducted among new users of this treatment using Quebec medico-administrative data. Patients still on the evidence-based HF drug treatment one year after initiation were considered persistent. Among persistent users, those with ≥88% of days covered by the treatment were deemed to have adequately implemented it. Persistent patients who have adequately implemented the treatment were considered adherent. To measure the association between, on one hand sex, and on the other persistence, implementation and adherence, adjusted proportion ratios (APR) with their 95% confidence intervals (CI) were calculated. Among 13,453 women, 72.1% were persistent, 72.2% adequately implemented the treatment, and 52.8% were adherent. Among the 14,614 men, these proportions were 73.6%, 67.9% and 50.1%, respectively. Men were less likely than women to be adherent to their treatment (APR: 0.96, 95% CI: 0.94–0.99). Among individuals initiating an evidence-based multi-drug treatment for HF, men are less likely than women to be adherent to this treatment.