Supporting GPs and people with hypertension to maximise medication use to control blood pressure: a pilot cluster RCT of the MIAMI intervention

Hypertension, or high blood pressure, is a key modifiable risk factor for heart disease and stroke. International guidelines have highlighted 'poor adherence to treatment' and 'physician inertia' as major barriers to effective blood pressure management. The Maximising Adherence, Minimising Inertia (MIAMI) intervention, a theory-based complex intervention, supports General Practitioners (GPs) and people with hypertension in maximising medication use to manage blood pressure. This pilot cluster randomised control trial (RCT) aimed to collect and analyse feasibility data to refine the MIAMI intervention and assess the feasibility of a definitive RCT. A pilot cluster RCT with a MIAMI intervention arm and usual care control arm was conducted. Quantitative data collection consisting of clinical measures and a self-report questionnaire took place at baseline and twelve week follow up. Semi-structured interviews with GP and patient participants were conducted. Fidelity (as measured by a protocol checklist and through qualitative interviews) and health economics costings were assessed. Six GP practices (intervention arm n = 3, control arm n = 3) and 52 patients (intervention arm n = 25, control arm n = 27) took part. All six GP practices and 92% of patients were retained. Fidelity, as measured by a checklist and through qualitative interviews, was good but three deviations from protocol were identified. Outcomes and measures used were acceptable. The implementation cost of the MIAMI intervention was estimated at €490 per participant. The qualitative data demonstrated that the intervention was considered acceptable and feasible by both GP and patient participants, except for the urine test component, which GPs found difficult to incorporate into practice due to logistical challenges. The MIAMI intervention was considered largely acceptable and feasible. Some changes to both intervention components and trial processes are required but with these in place a definitive RCT could be considered worthwhile. ISRCTN registry, ISRCTN85009436, registered 17/1/23.