Anastomotic leakage (AL) is a serious complication following intestinal surgery, despite advancements in surgical techniques. Defined as a defect in the intestinal wall at the anastomotic site, AL leads to communication between intra- and extraluminal compartments.(1) The variability in definitions and diagnostic criteria across studies complicates the assessment of AL incidence, with up to 24% reported in distal rectal surgeries, whereas the overall rates for intestinal surgeries range from 6%-7%. (2) Anastomotic leaks results in increased morbidity, mortality, and prolonged hospital stays. In colorectal cancer patients, AL has been linked to decreased long-term survival and higher local recurrence rates.(3) The clinical presentation of AL can vary widely, from subtle signs, such as low-grade fever and abdominal pain to severe conditions, such as sepsis and peritonitis. Early diagnosis is critical because delayed detection can lead to severe complications, including the need for reoperation and intensive care. Traditional diagnostic methods often fall short, necessitating imaging studies such as CT scans, which are more effective than contrast enemas in identifying leaks. Multiple risk factors contribute to the occurrence of AL, including surgical technique, local sepsis, ischemia at the anastomosis site, and patient-related factors such as age, obesity, and pre-existing health conditions.(4) Studies have shown that timely intervention can significantly reduce the mortality rates associated with AL, emphasizing the need for effective diagnostic tools. (5) C-reactive protein (CRP), a commonly used inflammatory marker, is frequently elevated in cases of AL. However, while CRP can indicate inflammation, it is often delayed in its rise and may not be as timely for the early detection of leaks compared to other diagnostic tools like the DULK score. The DULK Score a postoperative scoring system developed for the early detection of AL, has shown promise in previous studies, demonstrating early diagnosis and lower postoperative mortality.(7) This study aimed to evaluate the effectiveness and accuracy of the DULK Score in detecting AL following elective open intestinal anastomosis. Table 1: Various clinical parameters used to assess DULK score (4) Variables Threshold Scores Fever > 38o C 1 Respiratory rate > 30/min 1 Heart rate > 100/min 1 Oliguria <30 ml/h or 700 ml/d 1 Mental Status Agitation or lethargic 2 Clinical condition Deterioration 2 Ileus/Bowel obstruction Present 2 Gastric retention Present 2 Surgical wound dehiscence Present 2 Abdominal pain other than wound pain Present 2 Signs of infection Leucocytosis or elevated CRP 1 Renal function Creatinine elevation or urea by 5% 1 Nutrition Parenteral nutrition 2 CRP- C-Reactive Protein

Study population This was a prospective monocenter observational study that addressed patients undergoing elective intestinal anastomosis. Procedures involved benign (resection of polyps, ischemic colitis, diverticular disease, stoma reversal, crohn's or ulcerative colitis) as well as malignant disease (colonic or rectal malignancy). Inclusion criteria were patients ≥ 18 years old, undergoing elective intestinal anastomosis. Non-inclusion criteria were emergency operations. Post-operative protocol Post-operative clinical and laboratory parameters, were recorded on Day 3, 5, 7 and 12. These parameters were summed to determine the “Dulk-score”. Cut off value of Dulk score on day of leak was calculated and recorded. Outcome criteria The main endpoint of this study was the diagnosis of leak and calculation of efficacy of the score for early detection of AL in patients who had undergone intestinal anastomosis. The efficacy was evaluated by its sensitivity, specificity, positive and negative predictive values and the area under the ROC curve (AUC). Statistical analysis After multivariable analysis, ROC curves were established and the AUC were compared. Lastly, a predictive threshold for AL was determined according to the ROC curve (highlighting a strong sensitivity). The cut-off point and the AUC, sensitivity, specificity, positive and negative predictive values were calculated. Aim and objectives Aim was to assess the validity of the DULK Score as a tool for the early diagnosis of anastomotic leakage in the immediate post-operative period following intestinal anastomosis through an observational study. The objectives were: 1. To analyze the association between cut off value of DULK Score results and the occurrence of anastomotic leakage. 2. To evaluate the accuracy of the DULK Score cut off value in detecting anastomotic leakage.

Timing of leak and DULK Score cut off value The majority of leaks were identified on postoperative day 5 (56.2%), with only 2 leaks occurring beyond postoperative day 7. Table 1: Post op Day when leak is identified Post Op Day (POD) No of patients Percentage POD-3 4 12.5 % POD-5 18 56.25 % POD-7 8 25 % POD-12 2 6.25 % Total 32 Out of 32 patients who had leak 27 patients had DULK score of 8 while only 5 patients had score of less than 8. Table 2: DULK Score cut-off and Anastomotic leak DULK Score Leak No leak 8 or more 27 11 <8 5 43 Total 32 54 Descriptive results 32 patients developed anastomotic leak, the clinical manifestations were variable: systemic signs (66%), localized or generalized peritonitis, obstruction, fecal matter via drains or in feculent discharge from wound. Diagnosis was clinical in all cases and confirmed by CT scan. Diagnostic performance of Dulk score Dulk score was calculated for each patient starting from post-operative day 1 and then post-operative day 3, 5, 7 and 12. The value of Dulk score on the day of leak was calculated for each patient who developed leak. Table 3: Performance Metrics of Dulk Score (at cut-off score of 8) in our study Statistical data Values PPV 71.05 NPV 89.58 SENSITIVITY 84.37 SPECIFICITY 79.62 AUC (Area Under Curve) 81.99 % Comparison with CRP Table 4: Comparison of CRP and DULK Score for Early Detection of Anastomotic Leak Diagnostic parameter Leak No leak Sensitivity Specificity PPV NPV AUC No of Patients with CRP Rise Above 10 mg/L 18 (56.25%) 22 (40.74%) 56.25% 40.74% 45.00% 50.00% 0.53 No Rise in CRP Above 10 mg/L 14 (43.75%) 32 (59.26%) DULK Score ≥ 8 27 (84.37%) 11 (20.37%) 84.37% 79.62% 71.05% 89.58% 0.81 DULK Score < 8 5 (15.63%) 43 (79.63%)

The DULK score, established to reduce diagnostic delays and associated mortality rates, demonstrated good performance in our cohort, with a cut-off score of 8 yielding a sensitivity of 84.37% and specificity of 79.62%. These metrics highlight the score's utility in early detection, allowing for timely interventions that can significantly alter patient outcomes. DULK score outperforms CRP in the detection of anastomotic leaks, with higher sensitivity, specificity, and area under the curve (AUC). The CRP level, while helpful, can sometimes provide false negatives or be delayed in rising during the early postoperative days. Conversely, the DULK score appears to provide a more robust predictive tool, particularly with a cut-off score of 8. In our analysis of 86 patients, majority of leaks occurred on postoperative day 5 (56.2% of leaks), mirroring previous study done by Das et al (2013) that report a peak detection window between postoperative days 5 and 8.(6) These findings emphasize the need for vigilance in monitoring patients. Incorporating the DULK score into clinical practice or may enable healthcare providers to stratify risk more effectively and implement proactive management strategies, ultimately improving postoperative outcomes for patients undergoing anastomosis. The study's limitations include a single-centre design, potential subjectivity in DULK Score assessments, exclusion of certain patient groups (emergency surgeries), limited follow-up duration, unaccounted confounding variables, and variability in surgical techniques, affecting the generalizability of results.

The DULK score is a reliable and effective tool for the early detection of anastomotic leaks following intestinal surgery. With a sensitivity of 84.37% and specificity of 79.62%, it outperforms CRP in identifying leaks, particularly in the early postoperative period. Our study highlights the importance of using the DULK score to enable timely interventions, which can significantly improve patient outcomes. The DULK score shows promise in enhancing postoperative management and reducing complications associated with anastomotic leaks.

1. Hyman N, Manchester TL, Osler T, Burns B, Cataldo PA. Anastomotic leaks after intestinal anastomosis: it’s later than you think. *Ann Surg*. 2007 Feb 1;245(2):254–8. 2. Bruce J, Krukowski ZH, Al-Khairy G, Russell EM, Park KGM. Systematic review of the definition and measurement of anastomotic leak after gastrointestinal surgery. *Br J Surg*. 2001;88(9):1157–68. 3. Gray M, Marland JRK, Murray AF, Argyle DJ, Potter MA. Predictive and diagnostic biomarkers of anastomotic leakage: A precision medicine approach for colorectal cancer patients. *J Pers Med*. 2021;11(6):471. 4. Jina A, Singh UC. Factors influencing intestinal anastomotic leak and their predictive value. *Int Surg J*. 2019;6:4495-501. 5. Tsai YY, Chen WT. Management of anastomotic leakage after rectal surgery: a review article. *J Gastrointest Oncol*. 2019 Dec;10(6):1229-1237. doi: 10.21037/jgo.2019.07.07. 6. Smith RA, Jones R, Williams M. C-reactive protein as a marker for anastomotic leakage following colorectal surgery: A review of the literature. *Surg Infect*. 2020;21(5):450-455. doi: 10.1089/sur.2020.0205. 7. Daams F. Colorectal anastomotic leakage: Aspects of prevention, detection and treatment. *World J Gastroenterol*. 2013;19(15):2293.