Recruiting general practitioners and older patients with multimorbidity to randomized trials.

Background: Older patients with multimorbidity are under-represented in experimental research.

Objective: To explore the barriers and facilitators to general practitioner (GP) and older patient recruitment and retention in a cluster randomized controlled trial (RCT).

Method: This descriptive study uses qualitative and quantitative data from a cluster RCT, designed to evaluate the effectiveness of a medicines optimization intervention. The SPPiRE cluster RCT enrolled 51 general practices and 404 patients aged ≥65 years and prescribed ≥15 medicines. Quantitative data were collected from all recruited practices and 32 additional practices who were enrolled, but unable to recruit sufficient participants. Qualitative data were collected from purposive samples of intervention GPs (18/26), patients (27/208), and researcher logs and analysed thematically using inductive coding.

Results: Enrolment rates for practices and patients were 37% and 25%, respectively. Barriers to GP recruitment were lack of resources and to patient recruitment were difficulty understanding trial material and concern about medicines being taken away. GPs' primary motivation was perceived importance of the research question, whereas patients' primary motivation was trust in their GP. All general practices were retained. Thirty-five patients (8.6%) were lost to follow-up for primary outcomes, mainly because they had died and 45% did not return patient-reported outcome measures (PROMs).

Conclusion: Patient retention for the primary outcome was high, as it was collected directly from patient records. Patient completion of PROM data was poor, reflecting difficulty in understanding trial material. Recruiting older patients with multimorbidity to clinical trials is possible but requires significant resource and planning.

Trial registration: ISRCTN Registry ISRCTN12752680.