Undiagnosed Diabetes Mellitus is an important risk factor in secondary prevention after an acute coronary syndrome and warrants active screening

Abstract Background/Introduction Previous studies have shown that patients with Diabetes Mellitus (DM) undergoing percutaneous coronary intervention (PCI) for an acute coronary syndrome (ACS) have an increased ischemic risk compared to non-diabetics. This has led to the recommendation to take DM into account when considering extended dual antiplatelet therapy (DAPT) to prevent ischemic events. Although screening for DM can simply be conducted by measuring HbA1c values, the ACS guidelines do not yet recommend to screen for DM de novo. This may lead to undertreatment. Purpose We aimed to determine the ischemic risk of previously diagnosed DM and of DM de novo compared to patients without DM in a real world ACS population. Methods We included patients from the South East (Zuid Oost) Netherlands Heart Registry (ZON-HR) undergoing PCI for ACS without using oral anticoagulants and compared outcomes between DM and non-DM patients. In a subgroup of patients without previously diagnosed DM with available HbA1c measurements at baseline, we compared outcomes between patients with or without DM de novo (HbA1c ≥48 mmol/mol). All analyses were performed using Cox regression analysis. We used multivariate analysis to adjust for known ischemic risk factors. Results Of the 2406 patients included, 426 were previously diagnosed with DM. Additional ischemic risk factors, such as a history of myocardial infarction (MI), multivessel disease and kidney disease, were significantly more often present in patients with DM. Patients with DM showed numerically more major adverse cardiac and cerebral events (MACCE). However, this was not significant (HR: 1.24, 95% CI: 0.92-1.66). All-cause mortality was higher in patients with DM at 30 days (HR: 1.51, 95% CI 1.00-2.29) and 1 year (HR: 1.55, 95% CI 1.10-2.18), which remained significant at 1 year when corrected for additional risk factors. The HbA1c values at baseline were available in 387 patients without previously diagnosed DM. In this subgroup, 69 (18%) patients showed an elevated HbA1c level of ≥48 mmol/mol. Outcomes within this subgroup are presented in table 1. Patients with de novo DM showed significant more ischemic events after one month and one year follow-up compared to patients without DM de novo. Figure 1 depicts the survival from MACCE over time in these subgroups. Conclusion In our real world population of ACS patients undergoing PCI, we found no significant difference in ischemic risk between patients with previously diagnosed DM compared to non-DM. However, all-cause mortality was significant higher in DM patients. Active screening for DM resulted in a large proportion of patients with DM de novo who showed a major increase in ischemic risk. These results demonstrate the importance of screening for DM in ACS patients undergoing PCI.