An external pilot cluster randomised controlled trial of a theory-based intervention to improve appropriate polypharmacy in older people in primary care (PolyPrime): study protocol

Background: The use of multiple medications (polypharmacy) is a concern in older people (≥65 years) and is associated with negative health outcomes. For older populations with multimorbidity, polypharmacy is the reality and the key challenge is ensuring appropriate polypharmacy (as opposed to inappropriate polypharmacy). This external pilot cluster randomised controlled trial (cRCT) aims to further test a theory-based intervention to improve appropriate polypharmacy in older people in primary care in two jurisdictions, Northern Ireland (NI) and the Republic of Ireland (ROI).

Methods: Twelve GP practices across NI (n=6) and the six counties in the ROI that border NI will be randomised to either the intervention or usual care group. Members of the research team have developed an intervention to improve appropriate polypharmacy in older people in primary care using the Theoretical Domains Framework of behaviour change. The intervention consists of two components: (1) an online video which demonstrates how a GP may prescribe appropriate polypharmacy during a consultation with an older patient and (2) a patient recall process, whereby patients are invited to scheduled medication review consultations with GPs. Ten older patients receiving polypharmacy (≥4 medications) will be recruited per GP practice (n=120). GP practices allocated to the intervention arm will be asked to watch the online video and schedule medication reviews with patients on two occasions; an initial and a 6-month follow-up appointment. GP practices allocated to the control arm will continue to provide usual care to patients. The study will assess the feasibility of recruitment, retention and study procedures including collecting data on medication appropriateness (from GP records), quality of life and health service use (i.e. hospitalisations). An embedded process evaluation will assess intervention fidelity (i.e. was the intervention delivered as intended), acceptability of the intervention and potential mechanisms of action.

Discussion: This pilot cRCT will provide evidence of the feasibility of a range of study parameters such as recruitment and retention, data collection procedures and the acceptability of the intervention. Pre-specified progression criteria will also be used to determine whether or not to proceed to a definitive cRCT.

Trial registration: ISRCTN, ISRCTN41009897 . Registered 19 November 2019. ClinicalTrials.gov, NCT04181879 . Registered 02 December 2019.