Prognostic impact of pre-diabetes on patient outcomes after coronary artery bypass grafting: a single-center cohort study.

BACKGROUND Prediabetes, as a precursor stage, has an important role in development of overt diabetes as well as coronary artery disease (CAD). The aim of this study is to evaluate the association between prediabetes and adverse outcomes (major adverse cardiovascular and cerebrovascular events [MACCE] and all-cause mortality) in patients who underwent coronary artery bypass grafting (CABG). METHODS In this prospective study we included 3754 patients with CAD who underwent elective isolated CABG between January 2016 to January 2020. Patients were categorized based on their glycemic status at the time of CABG as follows: diabetics (n=2707), prediabetics (n=471) and nondiabetics (n=576). Primary endpoints were occurrence of all-cause mortality and MACCE. RESULTS We studied 3754 patients for a median of 32.25 months after CABG. MACCE occurred in 474 (12.6%) patients. After adjusting for potential confounders, diabetic patients had a higher risk of MACCE (Hazard ratio [HR] 1.69,95%CI: 1.24-2.29) and death (HR 2.33, 95%CI: 1.45-3.7) compared with nondiabetic and prediabetic ones. However, patients with pre-diabetes had lower HR of MACCE, but the association was non-significant (HR 1.02,95%CI: 0.67-1.56). CONCLUSION Diabetes is significantly associated with higher risk of mortality and MACCE; however, prediabetes did not show a prognostic impact in terms of overall and MACCE-free survival.