Association between Preoperative Hemoglobin A1c Levels and Surgical Site Infection in Diabetic Patients

Abstract

Background: Surgical site infections (SSIs) are among the most common postoperative complications and are associated with increased morbidity, prolonged hospitalization, and higher healthcare costs. Diabetes mellitus is a well-recognized risk factor for postoperative infections, and poor long-term glycemic control may further increase this risk. Hemoglobin A1c (HbA1c) is widely used as a reliable marker of chronic glycemic control; however, the relationship between preoperative HbA1c levels and postoperative SSI remains an important area of investigation. This study aims to evaluate the association between preoperative HbA1c levels and the incidence of SSIs within 30 days following elective surgery in diabetic patients.

Methods: This retrospective observational cohort study was conducted at Basrah Teaching Hospital, Basrah, Iraq, between June 2024 and June 2025. A total of 140 adult diabetic patients who underwent elective surgical procedures and had documented HbA1c measurements within three months prior to surgery were included. Patients were categorized into three groups based on HbA1c levels: good glycemic control (<7%), moderate control (7 - 8.9%), and poor control (≥9%). The primary outcome was the occurrence of SSIs within 30 days postoperatively according to Centers for Disease Control and Prevention criteria.

Results: The overall incidence of SSIs was 17.1% (24/140). SSI rates increased progressively with worsening glycemic control: 7.1% in patients with HbA1c <7%, 13.3% in patients with HbA1c 7 - 8.9%, and 34.2% in patients with HbA1c ≥9%. Multivariate logistic regression analysis demonstrated that poor glycemic control (HbA1c ≥9%) was an independent predictor of SSI after adjusting for age, body mass index (BMI), smoking status, and type of surgery.

Conclusion: Elevated preoperative HbA1c levels are significantly associated with an increased risk of SSIs following elective surgery. Routine assessment and optimization of glycemic control prior to surgery may help reduce postoperative complications in diabetic patients.