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

^*Sundus Mohammed Hasan Abbas
Medicine, FICMS, Family Medicine, Basrah Health Directorate, Iraq
Safa Hasan Hadi
Medicine, MBChB, F.I.B.M.S (General Surgery), Basrah Health Directorate, Iraq
Rabeea Hamad Qasim
Medicine, MBChB, C.B.M.S (General Surgery), Basrah Health Directorate, Iraq

^*Corresponding Author:

Sundus Mohammed Hasan Abbas
Medicine, FICMS, Family Medicine, Basrah Health Directorate, Iraq

Published on: 2026-04-24

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.

Keywords

Glycemic control, Hemoglobin A1c, Surgical site infection, Postoperative complications

Introduction

SSIs are among the most frequent healthcare-associated infections and represent a significant cause of postoperative morbidity, prolonged hospitalization, readmission, and increased healthcare expenditure worldwide [1]. Despite advances in surgical techniques and infection prevention strategies, SSIs continue to occur in approximately 2 - 5% of patients undergoing inpatient surgical procedures, with higher rates observed in high-risk populations [2]. Diabetes mellitus is a globally prevalent chronic metabolic disorder affecting hundreds of millions of individuals and is increasingly encountered in patients presenting for elective and emergency surgery [3].

Diabetes has consistently been identified as an independent risk factor for postoperative complications, particularly SSI [4]. Hyperglycemia impairs innate immune function by reducing neutrophil chemotaxis, adherence, phagocytosis, and intracellular killing of pathogens, thereby increasing susceptibility to infection [5]. In addition, chronic hyperglycemia disrupts collagen synthesis, angiogenesis, and fibroblast proliferation, all of which are essential components of normal wound healing [6].

Observational studies have demonstrated that patients with diabetes experience significantly higher rates of postoperative wound infection (WI) compared with non-diabetic individuals [7]. Furthermore, poor long-term glycemic control, as measured by elevated HbA1c, has been associated with increased postoperative infectious complications across multiple surgical specialties, including general surgery, orthopedics, and cardiac surgery [8-10]. HbA1c reflects average plasma glucose levels over the preceding two to three months and is widely accepted as a reliable indicator of chronic glycemic control [11].

Several studies suggest that elevated preoperative HbA1c levels are predictive of adverse surgical outcomes, including WI, delayed healing, prolonged hospital stay, and remission [8-10]. Current clinical guidelines emphasize the importance of perioperative glycemic optimization in reducing postoperative complications, recommending careful assessment and management of blood glucose in patients undergoing surgery [1]. However, the optimal HbA1c threshold that significantly increases the risk of SSIs remains controversial, with different studies proposing cutoff values ranging from 7% to 9% [9, 10]. Moreover, many patients with diabetes are primarily managed in family medicine or primary care settings, making preoperative glycemic optimization a shared responsibility between primary care physicians and surgeons. Understanding the relationship between preoperative HbA1c levels and postoperative SSIs is therefore essential to improving multidisciplinary perioperative care and reducing preventable complications. The present study aims to evaluate the association between preoperative HbA1c levels and the incidence of SSIs within 30 days following elective surgery.