Background Surgical site infections (SSIs) are one of the most frequent and costly postoperative complications, specifically in open abdominal procedures. Even transient hyperglycemia following surgery, commonly caused by the body's stress response, can compromise immune function and impair wound healing. While the association between diabetes and SSIs is established, the impact of postoperative hyperglycemia, particularly in non-diabetic patients, remains less clearly defined. This study evaluates whether postoperative hyperglycemia increases the risk of SSIs after open abdominal surgery. Methods A retrospective cohort analysis was conducted utilizing the TriNetX research platform, which compiles de-identified electronic health records from more than 180 healthcare organizations. Adult patients (≥18 years) who underwent open abdominal surgeries such as exploratory laparotomy, appendectomy, and colectomy were identified. Patients were categorized into two cohorts based on serum glucose levels measured within seven days postoperatively. The two groups were hyperglycemia (glucose ≥180 mg/dL) and normoglycemia (glucose <180 mg/dL). Propensity score matching balanced the cohorts on key demographics (age, sex, race, ethnicity), comorbidities including diabetes mellitus (ICD-10: E08–E13), hypertension (ICD-10: I10–I1A), ischemic heart disease (ICD-10: I20–I25), chronic kidney disease (ICD-10: N18), heart failure (ICD-10: I50), chronic obstructive pulmonary disease (ICD-10: J44), cerebrovascular disease (ICD-10: I60–I69), and baseline laboratory values (BMI, hemoglobin, creatinine, prothrombin time, albumin). The outcome was the incidence of SSIs within 30 days of surgery, identified using ICD-10 code T81.4. Results After matching, 78,147 patients were included in each cohort. The average age was 59 years, and the prevalence of diabetes (41.3%) and hypertension (59.8%) was similar. SSIs occurred in 6.0% of patients with postoperative hyperglycemia compared to 5.3% of those with normoglycemia, yielding a risk difference of 0.7% (95% CI: 0.5–1.0%, p < 0.001). Postoperative hyperglycemia was associated with a 13.7% increased risk of SSIs (risk ratio 1.137, 95% CI: 1.092, 1.184, p < 0.001). Additionally, the odds ratio for developing SSIs in the hyperglycemia group was 1.146 (95% CI: 1.098, 1.196, p < 0.001).

Conclusion Postoperative hyperglycemia significantly increases the risk of surgical site infections following open abdominal surgery. These findings suggest that postoperative glucose monitoring and glycemic management may reduce infection risk and improve surgical outcomes. Further prospective studies are needed to determine optimal glucose thresholds and intervention approaches that minimize complications without introducing additional risks.