Improvement in Hyperglycemia Prevents Surgical Site Infection Irrespective of Insulin Therapy in Non-diabetic Patients Undergoing Gastrointestinal Surgery

Intensive glycemic control is recommended to prevent surgical site infections (SSI). Our aim was to evaluate retrospectively the effect of improvement in hyperglycemia irrespective of insulin use on the incidence of SSI in non-diabetic patients. The highest blood glucose (BG) concentration within 12 h (early peak BG) and the final BG from 12 to 24 h after surgery were evaluated in patients who underwent gastrointestinal surgery. Patients with an early peak BG of ≥150 mg/dL were divided into those with persistent (final BG of ≥150 mg/dL) and improved hyperglycemia (final BG of <150 mg/dL). Patients without hyperglycemia and those with late-onset hyperglycemia were also assessed for SSI risk. Overall, 1612 patients were studied (diabetes, n = 293). Although hyperglycemia increased the SSI rates in non-diabetic patients, no correlation was demonstrated in patients with diabetes at any cutoff final BG defining htperglycemia except for 180 mg/dL. Hyperglycemia improved without insulin therapy in 283 of 512 non-diabetic patients who had early hyperglycemia. The adjusted standardized residual for those with SSI and persistent hyperglycemia was 5.2 (P < 0.05). In contrast, the absence of hyperglycemia was a significant preventive factor for SSI. In the multivariate analyses, persistent hyperglycemia was an independent risk factor for SSI (odds ratio 1.54; 95% confidence interval 1.03–2.31). Remission of hyperglycemia within 24 h after surgery prevented SSI in non-diabetic patients. Considering that hyperglycemia improved in approximately half of patients without insulin therapy, commencement of insulin dosing after two consecutive BGs of ≥150 mg/dL might be reasonable, especially in general wards.