Ischemic and bleeding risk by type 2 diabetes clusters in patients with acute coronary syndrome

The risk of ischemic events carried by different clusters of type 2 diabetes mellitus (DM) in the setting of secondary prevention is not definite and the association between DM and bleeding complications is controversial. We explored these issues in the START-ANTIPLATELET, a multicenter Italian registry including acute coronary syndrome (ACS) patients. Study outcome was 1-year incidence of the net composite endpoint including major adverse cardiovascular events (MACE) or any bleeding and its individual components across different DM strata (no DM, DM with or without insulin). Out of 951 patients, 20.0% had diabetes not on insulin and 2.5% had diabetes on insulin. The rate of the net composite endpoint was highest in patients receiving insulin (39.4 per 100 person-years vs 11.7 in diabetic patients not on insulin vs 14.0 in those without DM; p = 0.007). In DM, the higher risk of MACE was regardless of insulin use (p = 0.36). Conversely, the increase in bleeding complications was limited to patients on insulin (Hazard Ratio 2.31, 95% CI 0.93-5.71 vs no DM; p = 0.0105 across DM strata). On top of aspirin, the rates of the net composite endpoint were similar with ticagrelor/prasugrel or clopidogrel irrespective of DM status (p for interaction 0.63). In conclusion, in ACS patients, type 2 DM enhances the risk of MACE regardless of the DM cluster, whereas the propensity to bleeding related to DM seems confined to insulin-treated patients.