Adherence to heart failure treatment in patients with peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is characterized by left ventricular (LV) dysfunction developing towards the end of pregnancy or in the first months postpartum. Although about 60% of women with PPCM (the majority of which are prescribed evidence based heart failure [HF] medications) show LV recovery within 6 to 12 months, others remain with persistently impaired LV function. Poor adherence to medical therapy represents a major cause of avoidable hospitalizations, disability, and death in other cardiovascular conditions. In this study, we aimed to determine drug adherence to HF therapy among women with PPCM and to identify possible associations between drug adherence and LV recovery, functional status and psychological well-being.

In this single-centre, prospective, observational study, we included 36 consecutive women with PPCM. Adherence to HF treatment was assessed by (i) verifying the collection of pharmacy refills and (ii) using liquid chromatography high-resolution mass spectrometry (LC-HRMS). Participants were thereby classified as 'adherent' (i.e. all prescribed HF drugs were detectable by LC-HRMS), 'partially adherent' (i.e. at least one prescribed drug detectable) or 'non-adherent' (i.e. none of the prescribed drugs detectable). Health state index scores were assessed by EQ-5D-5L and HADS-A/D (for anxiety/depression). Patients' median age was 32.4 years (IQR 27.6-36.1). At the adherence visit (which occurred at a median of 16 months [IQR 5-45] after PPCM diagnosis), prescription included beta-blockers (77.8%), angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (75%), mineralocorticoid receptor antagonists (47.2%) and loop diuretics (95.2%). Less than two thirds of patients (63.9%) collected all their pharmacy refills in the 6 months prior to adherence visit. According to LC-HRMS, 23.5% participants were classified as adherent, 53.0% as partially adherent, and 23.5% as non-adherent. Adherence was associated with significantly lower LVEDD at follow-up (47 mm [IQR 46-52), vs. 56 mm [IQR 49-64] with partial adherence, and 62 mm [IQR 55-64] with non-adherence, P = 0.022), and higher LVEF at follow-up (60% [IQR 41-65]), vs. partially adherence (46% [IQR 34-50]) and non-adherence (41.0% [IQR 29-47], P = 014). Adherent patients had a lower overall EQ- 5D score (5.5 [IQR 5-7.5], vs. 6 [IQR 5-7] in partially adherent, and 10 [IQR 8-15] in non-adherent patients, P = 0.032) suggestive of a better self-rated health status.

Adherence to HF therapy was associated with favourable LV reverse remodelling in PPCM and better self-rated health status. Our study highlights the importance of drug adherence for functional recovery. Drug adherence should be an important component of patient communication and specific interventions in PPCM.