EP344 - Reevaluating Obesity and Risk of Anastomotic Leak after Elective Colectomy for Diverticulitis

Purpose/Background: Obesity (BMI ≥30 kg/m2) has been identified as an independent risk factor for anastomotic leak after left sided colon resection. However, obesity is a heterogeneous condition characterized by varying types and degrees of adiposity and metabolic health, so this simple categorization may not fully capture differences in surgical risk. The incremental effect of increasing BMI on anastomotic leak has not been well quantified. This study aimed to assess whether higher BMI was associated with greater risk of anastomotic leak after elective colectomy for diverticulitis.

Methods/Interventions: This 2-year retrospective cohort study utilized the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) Procedure Targeted Colectomy database from 2022-2023. Patients ≥18 who underwent elective colectomy with primary anastomosis without proximal diversion for diverticulitis were included. Patients were categorized by weight per World Health Organization definitions: overweight (25-29.9 kg/m²), class I obesity (30-34.9), class II obesity (35-39.9), and class III obesity (≥40). The primary outcome was any anastomotic leak; secondary outcomes included medical and surgical complications. A multivariable analysis was performed for the primary outcome to adjust for confounders and relevant clinical factors.

Results/Outcomes: Of 8687 patients (median age 59, 56% female, 91% white, 13% Hispanic) who underwent elective surgery for diverticulitis, 1817 (20%) of patients were non-obese, 2955 (34%) were overweight, 2195 (25%) were class I obese, 1128 (13%) were class II obese and 705 (8%) were class III obese. Obese patients were significantly younger overall (50 years for class III obesity vs. 65 years for non-obese, p< 0.001). A greater number of the obese patients had diabetes, chronic obstructive pulmonary disease (COPD), and and hypertension (p < 0.001 for all). The operative approach did not significantly differ based on BMI (p=0.124). Forty three percent of the cohort underwent robotic surgery (n=3660), 39% underwent hand assisted laparoscopic surgery (n=3323), 16% underwent laparoscopic surgery (n=1406), and 2% (n=208) underwent open surgery. The rate of anastomotic leak overall was 2.2% (n=183) and there were no significant differences by BMI category (0.562) (table 1). Operative time increased as BMI increased, though the differences were small (p < 0.001). A significantly greater number of obese patients had a superficial surgical site infection (p < 0.001). After adjusting for clinically significant variables, higher class of obesity did not increase incidence of anastomotic leak (Table 2).

Conclusion/Discussion: In this national sample of diverticulitis patients who underwent elective colectomy with primary anastomosis, the anastomotic leak rate was low overall and the risk of leak did not change as BMI increased. These findings from recent practice indicate that primary anastomosis without diversion may be a safe option in appropriately selected high BMI patients. This information can be useful to clinicians in planning operative approach and counseling patients.

Table 1. Primary and Secondary Outcomes by BMI Category
Table 2. Predictors of Anastomotic Leak, multivariable analysis