Improving Medicines use in People with Polypharmacy in Primary Care (IMPPP): Health economic evaluation of a complex intervention to improve prescribing appropriateness in patients with polypharmacy

Conference:

SAPC ASM 2024 - Bristol

Talk Code:

1B.5

Presenter:

Rupert Payne

Co-authors:

Ammar Annaw, Peter S. Blair, Barbara Caddick, Carolyn A. Chew-Graham, Tobias Dreischulte, Lorna J. Duncan, Bruce Guthrie, Nouf Jeynes, Cindy Mann, Deborah McCahon, Roxanne M. Parslow, Chris Salisbury, Katrina M. Turner, Nicholas L. Turner, Jeff Round

Author institutions:

University of Exeter, University of Bristol, Keele University, Ludwig-Maximilians-University (Munich), University of Edinburgh, Institute of Health Economics (Alberta, CA)

Problem

Polypharmacy is common and associated with undesirable consequences. Clinical management of polypharmacy is challenging in primary care because it requires balancing therapeutic benefits and risks, and clinical and patient priorities. It also requires overcoming important barriers to effective medication optimisation, such as suboptimal case-finding, inadequate clinical training, poor informatics solutions, and a failure to incentivise good care. Current strategies for managing polypharmacy are varied, and not supported by high quality evidence. The aim of the Improving Medicines use in People with Polypharmacy in Primary Care (IMPPP) trial was to evaluate the clinical and cost effectiveness of a complex intervention to optimise medication use for patients with polypharmacy in a general practice setting.

Approach

The IMPPP trial was a multicentre, open-label, cluster-randomised trial, with two parallel groups. 37 practices (19 intervention) were recruited from the South-West and West Midlands. Practices were randomised either to usual care, or to a complex intervention comprising a clinical informatics tool (designed to support medication review), case-finding, pharmacist and general practitioner (GP) training (focused on patient-centred care and medication review) and a four-stage structured medication review (pharmacist-led case-note review, inter-professional collaborative discussion between pharmacist and GP, patient-facing review, and follow-up if considered clinically indicated). Up to 50 patients receiving multiple (5+) regular medications and triggering at least one potentially inappropriate prescribing (PIP) indicator were recruited per practice. The primary outcome for the economic evaluation was quality adjusted life years, derived from patient-reported SF-12, and converted to SF-6D scores. The analytical approaches are cost-effectiveness and cost-utility analyses. Results of the primary economic analyses will be reported as net-benefit statistic, with ICERs and cost-effectiveness acceptability curves. The primary analysis is from the perspective of the NHS and personal social services. Cost-effectiveness ratios were based on the cost per incremental change in the primary clinical outcome (PIP). The cost per unit of change in PIP indicators was calculated using change in the count of PIP indicators at 26-weeks follow-up. The association between change in PIP and change in quality adjusted life years (QALY) during the same period will also be reported.

Findings

Study population was 1727 patients, median age 73 years (IRQ 66-79), with 51% male. Medication reviews were conducted between 4 Oct 2022 and 3 Oct 2023. Health economic analysis to evaluate cost-effectiveness is ongoing at present. Principal results will be reported at the SAPC 2024 Annual Scientific Meeting.

Consequences

IMPPP is one of the largest clinical trials of a complex intervention for polypharmacy. The intervention is readily scalable and aligns with current health service systems and processes. The results presented will establish the cost effectiveness of the IMPPP intervention with the potential to inform cost-effective change in the delivery of existing medication optimisation services, and consequent improvements in prescribing in a substantial proportion of patients.

Submitted by:

Rupert Payne

Funding acknowledgement:

This project was funded by the National Institute for Health Research (NIHR) under its Health and Social Care Delivery Research programme (Grant Reference Number 16/118/14). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.