Supporting Prescribing in Older Patients with Complex Multimorbidity and Significant Polypharmacy in Irish Primary Care: a cluster randomised controlled trial (SPPiRE study)

Background: This thesis had two broad aims. The first aim was to modify a complex potentially inappropriate prescribing (PIP) intervention in the context of a rapidly emerging evidence base. The second aim was to assess the effectiveness of the new supporting prescribing in older people in Irish primary care (SPPiRE) intervention in reducing polypharmacy and potentially inappropriate prescribing (PIP) in older people with multimorbidity and significant polypharmacy in Irish primary care.

Methods: Modifications were made to the context and content of the original intervention through an iterative process incorporating feedback from the multidisciplinary trial management team and emerging concepts from the literature. A cluster randomised controlled trial (RCT) that recruited practices who identified eligible patients, aged ≥ 65 years and prescribed ≥ 15 medicines was conducted. Practices were randomised using minimisation once baseline data collection was complete. Intervention GPs received access to the SPPiRE website, which contained professional training videos and the SPPiRE medication review template. Control GPs delivered usual care. It was not possible to blind participants or study personnel but an independent blinded pharmacist assessed primary outcome measures which were the number of repeat medicines and the proportion of patients with any PIP.

Results: Fifty-one general practices and 404 patients were recruited. Recruited participants had significant disease and treatment burden at baseline. Data was outstanding for nine participants at the time of submission of this thesis. All of the remaining 395 participants were included in the intention to treat analysis for primary outcomes. There was a small but significant reduction in the number of medicines at follow up in the intervention group (IRR 0.95, 95% CI; 0.89 – 0.99, p = 0.03). The adjusted odds of having at least one PIP at follow up in the intervention was 0.32 (95% CI; 0.11 – 0.94, p = 0.04), though the usefulness of this measure was limited by the low numbers with no PIP, and a varying effect was demonstrated on secondary PIP measures.

Discussion: The intervention was effective in reducing the number of medicines but the effect on PIP was unclear. Given the challenges in engaging this patient group, future medicines management multimorbidity studies should focus on patients who have moderate but not severe disease and treatment burden.