Undiagnosed (Pre)Diabetes as a Prevalent and Important Risk Factor for Recurrent Ischemic Outcomes in ACS Patients Undergoing PCI: Results of a Prospective Multicentre PCI Registry

Background: Diabetes is a known risk factor of acute coronary syndrome (ACS). However, diabetes de novo and prediabetes are also common in ACS patients. This study explored the prevalence of prediabetes and diabetes de novo in ACS patients, glucose-mediating therapy at discharge, and compared the prevalence of 30-day major adverse cardiac and cerebrovascular events (MACCE) in patients with prediabetes and diabetes de novo with known diabetes. Methods: ACS patients with measured haemoglobin A1c (HbA1c) from the South-East Netherlands Heart Registry, a prospective, multicentre registry of patients undergoing percutaneous coronary intervention (PCI), were analysed. Patients were stratified into two groups: known diabetes, and prediabetes (HbA1c 39–47 mmol/mol) or diabetes de novo (HbA1c ≥ 48 mmol/mol). Outcomes were analysed at 30 days post-PCI. Results: HbA1c was available in 34.1% of ACS patients (n = 1836), of whom 526 (28.7%) had known diabetes, 619 (33.7%) prediabetes, and 180 (9.8%) diabetes de novo. Compared with patients with known diabetes, patients with prediabetes and diabetes de novo had a significantly higher risk of MACCE (HR = 1.81, 95% CI 1.12–2.93, p = 0.016) after multivariable adjustment. At discharge, 59% of patients with diabetes de novo received no insulin, metformin, nor sodium-glucose co-transporter-2 inhibitor, compared with 16% of patients with known diabetes (p < 0.001). Conclusions: Impaired glucose metabolism without known diabetes was observed in nearly 45% of ACS patients and they demonstrated a significantly higher risk of 30-day MACCE compared with patients with known diabetes. Despite clear guideline recommendations, routine screening for hyperglycaemia and the appropriate initiation of glucose-mediating therapy remain underutilised in clinical practice.