A systematic review of randomised-controlled trials on deprescribing outcomes in older adults with polypharmacy.

Background: Mixed findings about deprescribing impact have emerged from varied study designs, interventions, outcome measures and targeting sub-categories of medications or morbidities. This systematic review controls for study design by reviewing randomised-controlled trials (RCTs) of deprescribing interventions using comprehensive medication profiles. The goal is to provide a synthesis of interventions and patient outcomes to inform healthcare providers and policy makers about deprescribing effectiveness.

Objectives: This systematic review aims to (1) review RCT deprescribing studies focusing on complete medication reviews of older adults with polypharmacy across all health settings, (2) map patients' clinical and economic outcomes against intervention and implementation strategies and (3) inform research agendas based on observed benefits and best practices.

Methods: The PRISMA framework for systematic reviews was followed. Databases used were EBSCO Medline, PubMed, Cochrane Library, Scopus and Web of Science. Risk of bias was assessed using the Cochrane Risk of Bias tool for randomised trials.

Results: Fourteen articles were included. Interventions varied in setting, preparation, use of interdisciplinary teams, validated guidelines and tools, patient-centredness and implementation strategy. Thirteen studies (92.9%) found deprescribing interventions reduced the number of drugs and/or doses taken. No studies found threats to patient safety in terms of primary outcomes including morbidity, hospitalisations, emergency room use and falls. Four of five studies identifying health quality of life as a primary outcome found significant effects associated with deprescribing. Both studies with cost as their primary outcome found significant effects as did two with cost as a secondary outcome. Studies did not systematically study how intervention components influenced deprescribing impact. To explore this gap, this review mapped studies' primary outcomes to deprescribing intervention components using the Consolidated Framework for Implementation Research. Five studies had significant, positive primary outcomes related to health-related quality of life (HRQOL), cost and/or hospitalisation, with four reporting patient-centred elements in their intervention.

Conclusions: RCT primary outcomes found deprescribing is safe and reduces drug number or dose. Five RCTs found a significant deprescribing impact on HRQOL, cost or hospitalisation. Important future research agendas include analysing (1) understudied outcomes like cost, and (2) intervention and implementation components that enhance effectiveness, such as patient-centred elements.