Specialist care of heart failure improves appropriate pharmacotherapy at the expense of greater polypharmacy and drug-interactions

Abstract

Background: There is growing concern at the nature and extent of polypharmacy in heart failure (HF), which may be associated with increased drug interactions, adverse drug effects and a poor understanding of and compliance with therapy.

Aims: This study evaluates polypharmacy in a relatively unselected community heart failure population following emergency admission and determines the impact of an in-hospital, specialist heart failure care programme on appropriate pharmacotherapy, polypharmacy and drug interactions.

Methods: We analysed the medication profiles of 91 consecutive patients with an emergency admission for HF to our institution on admission and discharge. The numbers of inappropriate medicines, inappropriate dosages and omitted medicines according to guidelines were recorded. Medication profiles were analysed for potential drug-drug, drug-liver and drug-kidney interactions using standard criteria.

Results: In the study population, average age 71.1+/-10.4 years, 65.9% were male, 68.1% had left ventricular systolic dysfunction and the average ejection fraction on transfer to the specialist HF service was 38+/-13%. A total of 66 inappropriate medicines, 107 omitted medicines and 37 inappropriate dosage regimens were identified in the cohort on admission. These figures had dropped to 31, 33 and 19, respectively, on discharge, with per patient averages decreasing significantly (all P<0.0001). However, polypharmacy and potential drug interactions increased by 33% and 62%, respectively, from admission to discharge (P<0.0001) as did drug-kidney interactions and drug-liver interactions. Only ischemic aetiology and hypercholesterolaemia predicted polypharmacy in this cohort on discharge, whereas age, sex, renal function and heart failure type did not.

Conclusions: Specialist care of heart failure following emergency admission results in more appropriate pharmacotherapy of heart failure. However, increased polypharmacy and drug-interactions are an inevitable consequence independent of age, sex and renal function. We advocate a practice of systematic evaluation of polypharmacy in all heart failure patients to identify potential problems and modify therapy where appropriate.