Diabetes, metformin and glucose lowering therapies after myocardial infarction: Insights from the SWEDEHEART registry

OBJECTIVE: To explore real-life use of glucose lowering drugs and prognosis after acute myocardial infarction (AMI) with a special focus on metformin. METHODS: Patients (n = 70270) admitted for AMI 2012–2017 were stratified by diabetes status and glucose lowering treatment and followed for mortality and MACE+ (AMI, heart failure (HF), stroke, mortality) until end of 2017 (mean follow-up time 3.4 ± 1.4 years) through linkage with national registries and SWEDEHEART. Hazard ratios (HR) were calculated in adjusted Cox proportional hazard regression models. RESULTS: Mean age was 68 ± 11 years and 70% were male. Of patients with diabetes (n = 16356; 23%), a majority had at least one glucose lowering drug (81%) of whom 51% had metformin (24% monotherapy), 43% insulin and a minority any SGLT2i/GLP-1 RA (5%). Adjusted HR for patients with versus without diabetes was 1.31 (95% CI 1.27–1.36) for MACE+ and 1.48 (1.41–1.56) for mortality. Adjusted HR for MACE+ for diabetes patients on metformin was 0.92 (0.85–0.997), p = 0.042 compared to diet treated diabetes. CONCLUSION: Diabetes still implies a high complication risk after AMI. Metformin and insulin were the most common treatment used in almost half of the diabetes population. Furthermore, patients treated with metformin had a lower cardiovascular risk after AMI and needs to be confirmed in prospective controlled trials.