The impact of preoperative HbA1c levels on predicting postoperative complications following abdominal surgery: The retrospective study

Diabetes mellitus (DM) is a factor for the development of postoperative complications. There is currently no consensus on a glycated hemoglobin (HbA1c) level that warrants delaying surgical intervention in patients undergoing abdominal surgery. In this study, preoperative HbA1c levels were assessed in patients undergoing different types of elective and urgent abdominal surgeries 2000 to 2023. Patients were categorized into groups based on their HbA1c levels: low (<8%) and high (≥8%). Postoperative complications and comorbidity data were analyzed using multivariable models. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Inclusion criteria included adult aged ≥18 years old undergoing abdominal surgery with available preoperative HbA1c data. Exclusion criteria were incomplete clinical records or missing HbA1c values. Patients with HbA1c ≥8% were included in the high group, following institutional convention. A total of 6,875 patients met the study criteria, with 6,082 patients (88.5%) having an HbA1c level <8% and 793 patients (11.5%) having an HbA1c level ≥8%, based on institutional convention and alignment with certain clinical guidelines that flag ≥8% as indicative of suboptimal glycemic control. Statistical analysis patients with an HbA1c level ≥8% had a significantly higher risk of complications, including surgical site infections (SSIs), urinary tract infections (UTIs) (p<0.001), and venous thromboembolism (VTE) (p=0.036). Emergency room (ER) readmissions within the 7- and 30-days post-surgery were more frequent in the high HbA1c group (p<0.001). Multivariable logistic regression identified a correlation between patient age and increased risk of SSIs (OR 1.01; 95% CI 1.00-1.02), UTIs (OR 1.04; 95% CI 1.03-1.05), VTE (OR 1.06; 95% CI 1.03-1.08), and ER readmissions (OR 1.01; 95% CI 1.00-1.01). Sensitivity analysis was performed using multivariable logistic regression models across HbA1c categories (<7%, 7–9%, and ≥9%), demonstrating a dose-response increase in complication risk with worsening glycemic control. Patients undergoing elective and urgent abdominal surgery with an HbA1c level ≥8% are at a higher risk of SSIs, VTE, and UTIs. These findings suggest that preoperative optimization of glycemic control may be beneficial when clinically feasible, particularly in elective cases.