Polypharmacy definition and prevalence in heart failure: a systematic review

Polypharmacy and heart failure are becoming increasingly common due to an ageing population and the rise of multimorbidity. Treating heart failure necessitates prescribing of multiple medications, in-line with national and international guidelines predisposing patients to polypharmacy. This review aims to identify how polypharmacy has been defined among heart failure patients in the literature, whether a standard definition in relation to heart failure could be identified and to describe the prevalence. The Healthcare Database Advanced Search (HDAS) was used to search EMBASE, MEDLINE, PubMed, Cinahl and PsychInfo from inception until March 2021. Articles were included of any design, in patients >= 18 years old, with a diagnosis of heart failure; that explicitly define and measure polypharmacy. Data were thereafter extracted and described using a narrative synthesis approach. A total of 7522 articles were identified with 22 meeting the inclusion criteria. No standard definition of polypharmacy was identified. The most common definition was that of " >= 5 medications." Polypharmacy prevalence was high in heart failure populations, ranging from 17.2 to 99%. Missing or heterogeneous methods for defining heart failure and poor patient cohort characterisation limited the impact of most studies. Polypharmacy, most commonly defined as >= 5 medications, is highly prevalent in the heart failure population. There is a need for an internationally agreed definition of polypharmacy, allowing accurate review of polypharmacy issues. Whether an arbitrary numerical cut-off is a suitable definition, rather than medication appropriateness, remains unclear. Further studies are necessary to understand the relationship between polypharmacy with specific types of heart failure and related comorbidities.