New onset diabetes in patients undergoing CABG: A single center registry analysis

Abstract

Abstract

Background: Diabetes mellitus is prevalent in 40–50% of patients undergoing coronary artery bypass grafting (CABG). While glycosylated hemoglobin (HbA1C) is common in this group, the incidence of new-onset diabetes after CABG remains uncertain.

Objectives: To determine the incidence of new-onset diabetes following CABG and its impact on intensive care unit (ICU) and hospital stay in a Pakistani cohort.

Methods: We analyzed retrospective data from hospital registry for consecutive adult patients undergoing CABG at a single tertiary care center from January 2025 to August 2025. Patients with known diabetes were excluded. Descriptive and comparative analyses were performed.

Results: Of 1,559 patients (1,355 men, 204 women), 933 without pre-existing diabetes  were included in the analysis. During hospitalization, 57 patients (6.1%) developed persistently elevated glucose levels at discharge, yielding an incidence of 61 ± 5 per 1,000. Compared with those who remained non-diabetic, patients with new-onset diabetes had similar age and body mass index but a higher prevalence of preoperative impaired HbA1C (44.6% vs. 13.7%). They also had longer ICU stay (102.0 ± 75 vs. 80.2 ± 29 hours) and hospital stay (11.7 ± 5.7 vs. 9.6 ± 2.4 days) (p < 0.001).

Conclusion: New-onset diabetes is unmasked in a notable proportion of non-diabetic patients following CABG, particularly among those with preoperative impaired HbA1C levels. Its occurrence is associated with prolonged ICU and hospital stay, highlighting the need for closer perioperative glucose surveillance in this high-risk population.

Keywords: CABG surgery, Diabetes, Impaired HbA1C, Intensive care unit