Informed shared decision-making programme on the prevention of myocardial infarction in type 2 diabetes: a randomised controlled trial

OBJECTIVE: To evaluate an informed shared decision-making programme (ISDM-P) for people with type 2 diabetes under high fidelity conditions. DESIGN: Randomised, single-blinded trial with sham control intervention and follow-up of 6 months. SETTING: Single-centre diabetes clinic providing care according to the national disease management programme in Germany. PARTICIPANTS: 154 people with type 2 diabetes without diagnosis of ischaemic heart disease or stroke. INTERVENTIONS: The ISDM-P is executed by diabetes educators. Core component is a patient decision aid on the prevention of myocardial infarction supplemented by a 90 min group teaching session. The structurally equivalent control intervention addresses stress issues. MAIN OUTCOME MEASURES: Primary outcome was risk comprehension, including realistic expectations about benefits and harms of interventions. It was assessed by a 12-item questionnaire after the teaching session when patients set and prioritise their treatment goals. Key secondary outcome was adherence to treatment goals, operationalised as achievement of individual goals and medication uptake. ISDM-P teaching sessions were video-taped to monitor intervention fidelity. RESULTS: 72 of 77 ISDM-P and 71 of 77 control patients completed the questionnaire (score 0–12). ISDM-P patients achieved higher levels of risk comprehension, mean score 8.25 vs 2.62, difference 5.63 (95% CI 4.82 to 6.44), and realistic expectations (score 0–6), 4.51 vs 0.85, 3.67 (3.23 to 4.11). More ISDM-P patients wished to take statins, 59.2% vs 30.4%, 28.7% (12.9% to 44.5%); more prioritised blood pressure control, 51.4% vs 25.7%, and fewer intensive glucose control, 33.3% vs 60%, p=0.002. More ISDM-P patients achieved their glycated haemoglobin goals, 95.8% vs 85.7%, 10.1% (0.6% to 19.5%). Achievement of prioritised goals and medication uptake were comparable between groups. CONCLUSIONS: The ISDM-P on preventive measures in type 2 diabetes was effective under high fidelity conditions. Involvement of diabetes educators may facilitate implementation of the informed shared decision-making. TRIAL REGISTRATION NUMBER: ISRCTN84636255.