Optimal perioperative care extends beyond surgical technique and anesthesia, with metabolic control emerging as a key determinant of patient outcomes. Among metabolic parameters, blood glucose levels play a particularly critical role. Perioperative dysglycemia—encompassing both hyperglycemia and hypoglycemia—is frequently observed in patients undergoing surgery, regardless of pre-existing diabetes status. This phenomenon is largely driven by the physiological stress response to surgery, characterized by increased secretion of counter-regulatory hormones such as cortisol, catecholamines, glucagon, and growth hormone, leading to enhanced gluconeogenesis, insulin resistance, and impaired peripheral glucose utilization (1,2). Hyperglycemia in the perioperative setting has been consistently associated with adverse clinical outcomes. Elevated blood glucose levels impair neutrophil function, reduce chemotaxis and phagocytosis, and promote a pro-inflammatory state. Additionally, hyperglycemia interferes with collagen synthesis and angiogenesis, thereby delaying wound healing. These mechanisms contribute to an increased risk of surgical site infections (SSI), prolonged hospital stay, and higher postoperative morbidity and mortality (3,4). Importantly, stress-induced hyperglycemia in non-diabetic individuals has also been shown to carry prognostic significance comparable to, or even exceeding, that in patients with known diabetes (1). Pharmacological modulation of perioperative glycemia, primarily through insulin therapy, has become a cornerstone of perioperative management. Insulin not only lowers blood glucose levels but also exerts pleiotropic effects, including anti-inflammatory actions, improved endothelial function, and modulation of lipid metabolism (2). Various insulin delivery strategies, such as continuous intravenous infusion and subcutaneous basal-bolus regimens, are employed depending on patient status and surgical complexity. Early studies advocated for intensive glycemic control (80–110 mg/dL), particularly in critically ill patients, demonstrating reduced mortality and complications (5). However, subsequent trials identified an increased risk of hypoglycemia without consistent survival benefit, prompting a shift toward more moderate targets. Current recommendations from the American Diabetes Association and the Society of Critical Care Medicine suggest maintaining perioperative blood glucose levels between 140 and 180 mg/dL in most patients to balance efficacy and safety (6,7). In addition to insulin, newer pharmacological agents such as glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors have gained attention in outpatient diabetes management. However, their perioperative use remains limited due to concerns regarding gastrointestinal intolerance, dehydration, and risk of ketoacidosis (1). Consequently, insulin continues to be the primary agent for perioperative glycemic control. Despite growing evidence and evolving guidelines, variability in clinical practice persists, particularly in resource-constrained settings. There is also a need for further studies evaluating the real-world impact of pharmacological glycemic modulation on surgical outcomes across diverse patient populations. Therefore, the present study aims to assess the effectiveness of pharmacological modulation of perioperative glycemic control and its impact on postoperative outcomes, including infection rates, wound healing, and duration of hospital stay in patients undergoing major surgery

Study Design and Setting A prospective, observational study was conducted jointly by the Departments of General Surgery and Pharmacology at a tertiary care teaching hospital over a period of 6 months. The study was designed to evaluate the impact of pharmacological modulation of perioperative glycemic control on surgical outcomes. Study Population A total of 180 patients scheduled for elective major surgical procedures were enrolled. Inclusion Criteria • Patients aged 18–75 years • Patients undergoing elective major surgeries (e.g., abdominal, gastrointestinal, hepatobiliary, and soft tissue surgeries) • Both diabetic and non-diabetic patients • Patients who provided written informed consent Exclusion Criteria • Emergency surgical procedures • Patients with severe hepatic, renal, or cardiac failure • Patients with active infection or sepsis preoperatively • Pregnant or lactating women • Patients on chronic steroid therapy or immunosuppressants Sample Size Calculation The sample size was estimated based on previous studies showing a reduction in postoperative complications with improved glycemic control. Assuming a difference of 15% in complication rates between groups, with 80% power and 5% level of significance, the required sample size was calculated to be 164 patients. To account for dropouts, a total of 180 patients were included. Grouping and Glycemic Targets Patients were categorized based on perioperative glycemic control: • Group A (Optimized Glycemic Control): Blood glucose maintained between 140–180 mg/dL • Group B (Suboptimal Glycemic Control): Blood glucose levels >180 mg/dL at any point during the perioperative period Grouping was done based on the mean perioperative blood glucose values recorded from preoperative period up to 48–72 hours postoperatively. Perioperative Glycemic Management Protocol Preoperative Management • Fasting blood glucose levels were recorded on the day of surgery • Oral hypoglycemic agents were withheld on the morning of surgery • Long-acting insulin doses were adjusted (50–80% of usual dose) Intraoperative Management • Blood glucose monitored every 1–2 hours • Intravenous insulin infusion initiated for glucose levels >180 mg/dL • Insulin titrated using a standardized sliding scale protocol Postoperative Management • Blood glucose monitored every 4–6 hours • Transition to subcutaneous basal-bolus insulin regimen once oral intake resumed • Target glucose range maintained between 140–180 mg/dL Statistical Analysis Data were entered into Microsoft Excel and analyzed using SPSS version 20.0. Continuous variables expressed as mean ± standard deviation (SD). Categorical variables expressed as percentages (%). Independent t-test used for comparison of continuous variables and Chi-square test used for categorical variables. Multivariate logistic regression analysis performed to identify independent predictors of postoperative complications. A p-value <0.05 was considered statistically significant Ethical Considerations The study was approved by the Institutional Ethics Committee (IEC) prior to initiation. Written informed consent was obtained from all participants

A total of 180 patients were included, with 92 in the optimized glycemic control group (Group A) and 88 in the suboptimal control group (Group B). Both groups were comparable in terms of demographic and clinical characteristics, with no statistically significant differences (p > 0.05), indicating good baseline homogeneity. Table 1: Baseline Characteristics Variable Group A (n=92) Group B (n=88) p-value Age (years) 51.8 ± 10.9 53.4 ± 11.8 0.38 Male (%) 56.5% 59.1% 0.72 Female (%) 43.5% 40.9% — BMI (kg/m²) 25.6 ± 3.2 26.1 ± 3.5 0.41 Diabetic patients (%) 45.6% 46.5% 0.89 Duration of surgery (hours) 2.8 ± 0.9 2.9 ± 1.1 0.65 Mean perioperative blood glucose levels were significantly lower in Group A compared to Group B (p < 0.001), confirming effective pharmacological glycemic control in the optimized group. Table 2: Perioperative Glycemic Profile Parameter Group A Group B p-value Mean glucose (mg/dL) 152 ± 18 228 ± 36 <0.001 Preoperative glucose 148 ± 20 210 ± 34 <0.001 Postoperative glucose 156 ± 16 235 ± 38 <0.001 Patients in the optimized glycemic control group experienced significantly fewer postoperative complications compared to the suboptimal group (14.1% vs 32.9%, p < 0.01), indicating a strong association between glycemic control and improved outcomes. Table 3: Postoperative Complications Complication Group A (n=92) Group B (n=88) p-value Any complication (%) 14.1% 32.9% <0.01 Surgical site infection (%) 8.7% 21.6% <0.01 Delayed wound healing (%) 10.8% 25.0% <0.01 Sepsis (%) 3.2% 9.1% 0.08 The mean duration of hospital stay was significantly shorter in Group A compared to Group B (7.2 ± 2.1 vs 10.5 ± 3.4 days, p < 0.001), suggesting faster recovery in patients with optimized glycemic control. Table 4: Length of Hospital Stay Parameter Group A Group B p-value Hospital stay (days) 7.2 ± 2.1 10.5 ± 3.4 <0.001 The incidence of hypoglycemia was low and comparable between both groups, with no statistically significant difference (p = 0.76), indicating that pharmacological glycemic control was achieved safely. Table 5: Incidence of Hypoglycemia Parameter Group A Group B p-value Hypoglycemia (%) 4.3% 3.4% 0.76 Multivariate logistic regression analysis was performed to identify independent predictors of postoperative complications after adjusting for confounding variables. Suboptimal glycemic control (>180 mg/dL) was found to be a significant independent predictor of adverse outcomes. Table 6: Multivariate Logistic Regression Analysis Variable Adjusted Odds Ratio (AOR) 95% Confidence Interval p-value Suboptimal glycemic control (>180 mg/dL) 2.94 1.52 – 5.68 <0.01 Age (>60 years) 1.41 0.78 – 2.54 0.24 BMI (>25 kg/m²) 1.36 0.75 – 2.47 0.30 Diabetes mellitus 1.58 0.88 – 2.82 0.12 Duration of surgery (>3 hours) 2.12 1.15 – 3.89 0.01

The present study evaluated the impact of pharmacological modulation of perioperative glycemic control on surgical outcomes and demonstrated that maintaining blood glucose levels within a target range of 140–180 mg/dL is associated with significantly improved postoperative outcomes. Patients with optimized glycemic control had lower rates of surgical site infections, reduced overall complications, and shorter hospital stays, without an increase in hypoglycemic events. These findings reinforce the growing body of evidence supporting controlled perioperative glycemia as a critical determinant of surgical prognosis. Perioperative hyperglycemia is a well-recognized consequence of the surgical stress response, mediated by increased secretion of counter-regulatory hormones and inflammatory cytokines. This metabolic disturbance leads to insulin resistance and elevated circulating glucose levels even in non-diabetic individuals. Previous studies have demonstrated that hyperglycemia adversely affects immune function by impairing neutrophil activity, reducing phagocytosis, and promoting a pro-inflammatory environment, thereby increasing susceptibility to infections (8,9,10). The significantly higher rate of surgical site infections observed in the suboptimal glycemic group in the present study is consistent with these mechanisms. Our findings are consistent with earlier clinical studies that have established perioperative hyperglycemia as an independent predictor of postoperative morbidity. Ata et al. demonstrated a strong association between postoperative hyperglycemia and surgical site infections (3). Similarly, a meta-analysis by Sathya et al. confirmed that improved glycemic control reduces postoperative complications across different surgical populations (4). More recent analyses have further emphasized that even mild elevations in perioperative glucose levels can adversely affect outcomes, highlighting the need for early intervention (10,11). Insulin remains the cornerstone of pharmacological glycemic control in the perioperative period. Beyond its glucose-lowering effects, insulin exerts anti-inflammatory and endothelial-protective actions that may contribute to improved tissue perfusion and wound healing. In the present study, insulin-based protocols were effective in maintaining glycemic targets and improving outcomes. These findings are in line with the observations of Duggan et al., who highlighted the benefits of structured insulin therapy in perioperative care (2), and with subsequent clinical recommendations supporting protocol-driven insulin administration (11). The results of this study also align with current guideline recommendations. The American Diabetes Association recommends maintaining perioperative blood glucose levels between 140 and 180 mg/dL in most hospitalized patients (6). Likewise, the Society of Critical Care Medicine advocates moderate glycemic control to minimize the risk of hypoglycemia while ensuring adequate metabolic control (7). Emerging perioperative care guidelines also emphasize individualized glycemic targets based on patient risk profiles and surgical complexity (11,12). The multivariate logistic regression analysis in this study identified suboptimal glycemic control as an independent predictor of postoperative complications, with nearly threefold increased odds. This finding is supported by previous studies demonstrating that perioperative hyperglycemia independently contributes to adverse outcomes, irrespective of underlying comorbidities (10,12). Additionally, prolonged duration of surgery was found to be a significant predictor, which may reflect increased physiological stress and exposure to infection risk. An important observation in this study is the impact of stress-induced hyperglycemia in non-diabetic patients. This has been increasingly recognized as a clinically significant phenomenon. Umpierrez and Pasquel reported that inpatient hyperglycemia, even in patients without known diabetes, is associated with worse outcomes and should be actively managed (1). This underscores the need for universal glucose monitoring in surgical patients. The incidence of hypoglycemia in the present study was low and comparable between groups, indicating that pharmacological glycemic control can be implemented safely with appropriate monitoring. This is consistent with recent evidence suggesting that moderate glycemic targets reduce the risk of hypoglycemia without compromising clinical benefits (11).

The findings of this study emphasize that pharmacological modulation of perioperative glycemic control plays a pivotal role in improving surgical outcomes. Maintaining blood glucose within a moderate target range significantly reduces postoperative complications and enhances recovery, supporting current guideline recommendations.

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