Title : BMI-dependent surgical approach selection and risk of postoperative complications in elderly patients undergoing pancreaticoduodenectomy: Insights into the gut microbiota link
Abstract:
Objective: This study aimed to identify the risk factors associated with postoperative complications in elderly patients (≥65 years) undergoing pancreaticoduodenectomy, determine the key moderating factor influencing the choice of surgical approach (open vs. minimally invasive), and preliminarily explore the potential influence of gut microbiota alterations between patients with different BMI levels on the development of postoperative complications. The ultimate goal was to provide evidence-based guidance for individualized surgical decision-making and complication prevention in the elderly population.
Methods: A retrospective cohort study was conducted including 158 elderly patients (aged ≥65 years) who underwent pancreaticoduodenectomy at the First Affiliated Hospital of Harbin Medical University between January 1, 2020, and September 30, 2025. Postoperative complications were defined as the occurrence of postoperative hemorrhage, delayed gastric emptying, pneumonia, or pleural effusion within 30 days after surgery. Data preprocessing involved BMI stratification and binary classification of complication status. Multivariate logistic regression analyses were performed to identify independent risk factors, with a particular focus on the interaction between surgical approach and BMI, age, number of chronic comorbidities, preoperative hemoglobin (Hb), and albumin levels. Model stability was evaluated using the variance inflation factor (VIF), and interaction risk analysis with visualization was applied to determine the BMI threshold for optimal surgical approach selection. Additionally, preliminary analyses of 16S rRNA sequencing data were conducted to compare gut microbiota profiles between high- and low-BMI groups and to examine their associations with postoperative complications.
Results: Multivariate logistic regression revealed that the interaction between BMI and surgical approach was an independent moderator of postoperative complications (interaction term: OR = 1.370, 95% CI: 1.088–1.765, P = 0.0101). The calculated BMI intersection point was 20.7 kg/m², indicating that minimally invasive surgery was associated with a lower complication risk when BMI < 20.7 kg/m², whereas open surgery appeared preferable when BMI > 20.7 kg/m². No significant interactions were identified between surgical approach and age, comorbidity count, preoperative Hb, or albumin levels (all P > 0.05). VIF values for all variables were < 6, confirming the absence of severe multicollinearity. Preliminary microbiota analyses demonstrated distinct compositional differences between high- and low-BMI groups, and these variations were potentially associated with the incidence of postoperative hemorrhage, delayed gastric emptying, pneumonia, and pleural effusion.
Conclusion: BMI serves as a crucial moderating factor in determining the optimal surgical approach for elderly patients undergoing pancreaticoduodenectomy. A BMI threshold of 20.7 kg/m² may serve as a reference point for individualized decision-making in this population. Moreover, BMI-related alterations in gut microbiota composition may contribute to the development of major postoperative complications, offering novel insights and potential targets for precision prevention and management strategies in elderly patients receiving pancreaticoduodenectomy.
