Objective To investigate the influencing factors for biliary leakage after pancrea-ticoduodenectomy (PD) and the prognosis.

Methods The retrospective case‑control study was conducted. The clinicopathological data of 1 521 patients who underwent PD between January 2022 and December 2023 were collected, including 336 cases in BenQ Pancreatic Disease Hospital Affiliated to Nanjing Medical University and 1 185 cases in The First Affiliated Hospital of Nanjing Medical University. There were 912 males and 609 females, aged 65(56,71) years. Observation indicators: (1) incidence of biliary leakage after PD; (2) comparison of clinical outcomes among patients with different grades of biliary leakage; (3) analysis of influencing factors for biliary leakage after PD. For measurement data with skewed distribution, the Mann‑Whitney U test was used for comparison between groups and Kruskal‑Wallis test was used for multi group comparison. Comparison of count data between groups was analyzed using the the chi‑square test or Fisher exact probability. The post‑hoc pairwise comparison was performed using the Bonferroni-Dunn method after the overall difference was statistically significant. Univariate analysis was performed using the corresponding statistical methods based on data types. Multivariate analysis was performed using the Logistic regression model.

Results (1) Incidence of biliary leakage after PD: among the 1 521 patients, 46 cases developed biliary leakage postoperatively, including 19 cases of grade A, 24 cases of grade B, and 3 cases of grade C. (2) Comparison of clinical outcomes among patients with different grades of biliary leakage: there were significant differences among patients without biliary leakage, those with grade A biliary leakage, and those with grade B+C biliary leakage in terms of postoperative pancreatic fistula, hemorrhage, gastroplegia, intra‑abdominal infection, sepsis, pulmonary complications, wound complications, severe complications, comprehensive complication index (CCI), postoperative invasive interventions, intensive care unit (ICU) treatment, duration of postoperative hospital stay, in‑hospital mortality, postoperative 90‑day mortality, and hospitalization costs (χ²=42.24, 20.28, 7.14, 58.72, 37.11, 36.56, 7.21, 49.99, H=69.13, χ²=23.46, 7.10, H=35.67, χ²=13.74, 13.77, H=24.20, P<0.05). Further post‑hoc pairwise analysis showed that there were significant differences in postoperative pancreatic fistula, hemorrhage, CCI, postoperative invasive interventions, duration of postoperative hospital stay, and hospitalization costs between patients without biliary leakage and patients with grade A biliary leakage (P<0.017). There were significant differences in postoperative pancreatic fistula, hemorrhage, gastroplegia, intra‑abdominal infection, sepsis, pulmonary complications, severe complications, CCI, postoperative invasive interventions, duration of postoperative hospital stay, in‑hospital mortality, postoperative 90‑day mortality, and hospitalization costs between patients without biliary leakage and patients with grade B+C biliary leakage (P<0.017). (3) Analysis of influencing factors for biliary leakage after PD. Results of multivariate analysis showed that preoperative biliary drainage, preoperative neutrophil-to-lymphocyte ratio >5, bile duct diameter ≤4 mm, and volume of intraoperative blood loss >400 mL were independent risk factors for biliary leakage after PD (odds ratio=2.30, 2.65, 15.47, 2.09, 95% confidence interval as 1.08-4.88, 1.34-5.23, 7.42-32.28, 1.05-4.16, P<0.05).

Conclusions Preoperative biliary drainage, preoperative neutrophil-to-lymphocyte ratio >5, bile duct diameter ≤4 mm, and volume of intraoperative blood loss >400 mL are independent risk factors for biliary leakage after PD. The occurrence and severity of biliary leakage can affect the postoperative poor outcomes of patients.