Diabetes mellitus, glycemic control, and risk of postoperative infectious complications in gastric and colorectal cancer surgery

Abstract

The rising global prevalence of diabetes mellitus increasingly affects outcomes in gastrointestinal surgery. Patients undergoing gastric or colorectal cancer surgery often present with metabolic comorbidities that may compromise postoperative recovery. The study from Peng et al on the issue of World Journal of Gastrointestinal Surgery, highlights that a history of diabetes and poor glycemic control, reflected by elevated glycated hemoglobin levels, are significant predictors of postoperative infectious complications, including surgical site infections and systemic infections. Hypoalbuminemia was also identified as an independent risk factor, emphasizing the interplay between metabolic status and nutritional reserves. Chronic hyperglycemia impairs immune function, collagen synthesis, and tissue perfusion, directly compromising anastomotic integrity and increasing the risk of surgical site infections, while surgical stress further exacerbates perioperative metabolic imbalance. These findings underscore the importance of comprehensive preoperative metabolic assessment, strict perioperative glycemic management, and nutritional optimization to reduce postoperative morbidity in diabetic patients undergoing gastrointestinal cancer surgery.

Key Words: Diabetes mellitus; Gastric cancer; Colorectal cancer; Postoperative complications; Surgical site infection; Glycemic control; Anastomotic leak

Core Tip: Diabetes mellitus and perioperative hyperglycemia significantly increase the risk of infectious complications and anastomotic failure in gastrointestinal surgery. The recent findings by Peng et al underscore that preoperative glycated hemoglobin levels and albumin status are essential biomarkers for risk stratification. Beyond systemic infections, metabolic dysfunction directly impairs collagen synthesis, linking hyperglycemia to surgical site infections and micro-leaks. Surgeons must adopt a multidisciplinary approach focused on glycemic control and nutritional optimization to mitigate these risks in the growing population of diabetic oncologic patients.

This editorial refers to “Impact of diabetes mellitus history on postoperative infectious complications in gastric or colorectal cancer patients” by Peng et al, 2026; https://doi.org/10.4240/wjgs.117631

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INTRODUCTION

The growing global prevalence of diabetes mellitus, a metabolic disorder characterized by impaired insulin secretion and/or reduced tissue sensitivity to insulin, is increasingly influencing outcomes in gastrointestinal (GI) surgery. Patients undergoing surgery for gastric and colorectal malignancies frequently present with metabolic comorbidities that may negatively affect postoperative recovery. In this editorial, we comment on the article by Peng et al[1] published in World Journal of Gastrointestinal Surgery, evaluating the impact of diabetes history on postoperative infectious complications in patients with gastric or colorectal cancer provides important insights into the interaction between metabolic disease and surgical outcomes. In a cohort of 200 patients, postoperative infectious complications occurred in 24.0% of cases, with a markedly higher prevalence of diabetes among affected individuals (52.1% vs 24.3%, P < 0.001). Multivariate analysis further confirmed diabetes as an independent risk factor [odds ratio (OR) = 3.335, 95% confidence interval: 1.532-7.258], while poor glycemic control [glycated hemoglobin (HbA1c) ≥ 7.0%] showed an even stronger association (OR = 6.524). Hypoalbuminemia (albumin < 35 g/L) also emerged as an independent predictor (OR = 2.678), highlighting the interplay between metabolic and nutritional status[1]. These findings add to the growing evidence that perioperative metabolic status is a critical determinant of postoperative morbidity in abdominal surgery[1-4].

CONTEXT OF THE STUDY

Postoperative infections remain among the most frequent complications following major GI surgery. Surgical site infection, pneumonia, urinary tract infection, and intraabdominal abscesses significantly contribute to prolonged hospitalization, increased healthcare costs, and worse oncologic outcomes[2,5]. Diabetes mellitus is widely recognized as a risk factor for postoperative complications due to its impact on immune response, tissue perfusion, and wound healing. Chronic hyperglycemia impairs neutrophil function, reduces collagen synthesis, and promotes microvascular damage, ultimately compromising tissue repair processes[3,6]. In the study analyzed, Peng et al[1] identified diabetes history and poor glycemic control as significant predictors of postoperative infectious complications. The authors observed a postoperative infection rate consistent with previously reported rates in colorectal and gastric oncologic surgery[1,7,8]. Importantly, the study also identified hypoalbuminemia as an independent predictor of postoperative infection. Hypoalbuminemia has been consistently associated with adverse surgical outcomes, particularly in GI cancer surgery, as albumin levels reflect both nutritional reserves and systemic inflammatory response two factors crucial for tissue repair and immune competence[9-11]. Malnutrition, sarcopenia, and metabolic disease frequently coexist in GI oncology patients, and when combined with diabetes, these conditions substantially increase the risk of infectious complications after major abdominal surgery. These findings underscore the complex interplay between metabolic control, nutritional status, and surgical outcomes in this high-risk population further emphasizing the need for integrated metabolic and nutritional assessment.

MECHANISMS LINKING DIABETES AND POSTOPERATIVE INFECTIONS

From a pathophysiological perspective, diabetes mellitus is characterized by chronic hyperglycemia, insulin resistance, and a persistent low-grade inflammatory state, all of which predispose patients to postoperative infectious complications. Chronic hyperglycemia alters neutrophil chemotaxis and phagocytosis, impairs complement activation, and promotes a pro-inflammatory cytokine imbalance, thereby weakening host immune defenses[6,10,11]. Surgical stress further exacerbates metabolic disturbances by inducing insulin resistance and hyperglycemia through catecholamine, cortisol, and inflammatory mediator release, effects that are amplified in diabetic patients[12]. Additionally, diabetes causes microvascular damage, reducing tissue oxygenation and perfusion, which are critical for collagen synthesis, bacterial clearance, wound and anastomotic healing. Importantly, hyperglycemia also directly affects tissue repair and anastomotic integrity. Elevated perioperative glucose levels impair fibroblast proliferation, collagen deposition, and alter extracellular matrix remodeling, ultimately decreasing the mechanical strength and weakening anastomotic integrity. This may increase susceptibility to subclinical or clinical leaks, which in turn predispose to subsequent infectious complications, including deep surgical site infections, intra-abdominal abscesses and peritonitis[12-15]. These mechanisms collectively establish a strong biological link between metabolic dysregulation and one of the most severe postoperative complications, reinforcing the clinical relevance of glycemic control in surgical patients as observed by Peng et al[1].

CLINICAL IMPLICATIONS FOR GI SURGERY

The findings of Peng et al[1] have important implications for surgeons managing GI malignancies. Preoperative assessment should include evaluation of glycemic control through measurement of HbA1c. Long-term glycemic control provides valuable information regarding metabolic stability and may help identify high-risk patients before surgery. In this context, HbA1c may serve not only as a diagnostic marker but also as a practical tool for perioperative risk stratification, helping to guide the intensity of glycemic optimization strategies[4]. Second, perioperative glycemic control protocols should be implemented in patients undergoing major abdominal surgery, as maintaining blood glucose within controlled ranges significantly reduces the incidence of postoperative infections[9-11]. Third, nutritional optimization should be considered a key component of perioperative management. Prehabilitation strategies including nutritional supplementation, correction of hypoalbuminemia, and metabolic optimization may reduce postoperative complications in GI oncology surgery[9,16,17]. Among the various nutritional screening tools, the nutrition risk screening 2002 and the malnutrition universal screening tool are the most widely used and validated in clinical and perioperative settings, due to their simplicity, reproducibility, and good predictive performance[18]. In addition, poor glycemic control and insulin resistance have been associated with sarcopenia and reduced muscle mass, even in patients with normal or elevated body mass index. This highlights the close relationship between metabolic dysregulation and nutritional status, suggesting that HbA1c assessment, when combined with nutritional screening tools, may help identify patients at higher risk of adverse postoperative outcomes. Furthermore, in colorectal surgery, particularly in left-sided and rectal procedures, the combined use of mechanical bowel preparation and oral antibiotics has been associated with a reduction in surgical site infections, supporting a multimodal approach to infection prevention[19-22]. Finally, multidisciplinary collaboration involving surgeons, anesthesiologists, endocrinologists, and nutrition specialists is essential for optimal perioperative management of diabetic patients. Integration of glycemic control and metabolic optimization within enhanced recovery after surgery (ERAS) pathways, including preoperative carbohydrate loading, avoidance of prolonged fasting, early postoperative feeding, defined glucose targets, structured perioperative glucose monitoring, and standardized insulin protocols, may further improve postoperative outcomes in high-risk patients by attenuating insulin resistance and reducing surgical stress responses[17,23,24].

In addition, nutritional parameters such as serum albumin levels should be monitored and corrected as part of ERAS-based metabolic optimization, given the independent association between hypoalbuminemia and infectious complications (OR = 2.678 in Peng et al[1]). Diabetes mellitus is increasingly prevalent and is associated with higher need for surgery and an increased risk of postoperative complications. Current guidelines focus on preoperative optimization, perioperative management of hypoglycemic therapy, intraoperative glycemic control, and postoperative care[25-27].

LIMITATIONS OF THE STUDY

Despite its relevance, the study presents several limitations. The retrospective design limits the ability to establish causal relationships and introduces potential selection bias. Additionally, the relatively small sample size and single-center design may reduce the generalizability of the results. Another limitation concerns the lack of detailed information regarding perioperative glucose management protocols. Differences in insulin therapy, intraoperative glucose monitoring, and postoperative glycemic control may significantly influence surgical outcomes. Furthermore, gastric and colorectal procedures were analyzed together despite differences in surgical complexity and complication profiles. Future studies should evaluate these populations separately to better identify procedure-specific risk factors.

FUTURE PERSPECTIVES

Further prospective studies are required to clarify the optimal strategies for metabolic optimization in GI cancer surgery. Large multicenter studies may help identify clinically meaningful HbA1c thresholds associated with increased postoperative risk. Randomized trials evaluating preoperative glycemic optimization programs could provide stronger evidence supporting targeted interventions before elective GI surgery. Technological advances such as continuous glucose monitoring systems and individualized insulin therapy protocols may also improve perioperative metabolic control. In addition, innovations in anastomotic protection, including advanced sealants, and technologies such as indocyanine green fluorescence imaging to assess tissue perfusion, may help reduce the risk of clinical or subclinical anastomotic leaks. Greater adherence to current perioperative management guidelines, focusing on preoperative metabolic optimization, appropriate management of hypoglycemic therapy, intraoperative glycemic control, and attentive postoperative care, represents a promising strategy to reduce postoperative morbidity in diabetic patients undergoing abdominal surgery[23,26-28].

CONCLUSION

The study by Peng et al[1] reinforces the growing evidence that diabetes mellitus represents an important risk factor for postoperative infectious complications in gastric and colorectal cancer surgery. Poor glycemic control and hypoalbuminemia appear to significantly increase this risk. This observation suggests that glycemic burden, rather than the diagnosis of diabetes alone, may represent a key determinant of postoperative infectious risk[1,29,30]. For GI surgeons, these findings highlight the importance of comprehensive metabolic evaluation, nutritional optimization, and strict perioperative glycemic management. As the prevalence of diabetes continues to rise globally, integrating metabolic optimization strategies into surgical pathways will become increasingly essential to improve outcomes in patients undergoing GI oncologic surgery.

ACKNOWLEDGEMENTS

The author gratefully acknowledges Prof. Cappellani A for his valuable mentorship, for inspiring the development of this topic, and for his careful review of the manuscript.