Patients with Class III Obesity are at Elevated Risk of Postoperative Morbidity Following Surgery for Left-Sided Diverticular Disease: A Retrospective Population Level Study.

Abstract

Background: While obesity is a well-established risk factor for the development of diverticular disease, studies focusing on the impact of body mass index (BMI) on postoperative outcomes require updating. We designed this population-level retrospective cohort study to evaluate the impact of BMI on postoperative outcomes following operative intervention for left-sided diverticular disease.

Methods: This was a population-based retrospective cohort study using the Healthcare Cost and Utilization Project National Inpatient Sample (NIS) (September 1, 2015-December 31, 2019). ICD-10-CM codes were utilized to identify a cohort of adult patients with a primary admission diagnosis of diverticulitis. Patients were stratified according to obesity status (i.e., not obese: BMI under 30kg/m²; class I obesity: BMI 30-34.9kg/m²; class II obesity: BMI 35-39.9kg/m²; class III obesity: BMI greater than 40kg/m²). The primary outcome was overall in-hospital postoperative morbidity. Multivariable regression models were fit.

Results: There were 33,029 patients identified in the NIS who underwent left-sided colonic resection for diverticular disease. There were 27,212 patients who were not obese, 2,209 patients with class I obesity, 1,710 patients with class II obesity, and 1,898 patients with class III obesity. Patients with class III obesity (i.e., BMI greater than 40), had 72.7% higher odds (95% CI 1.54-1.94) of experiencing in-hospital postoperative morbidity as compared to patients with BMI less than 30. Patients in with class III obesity had 26.9% higher odds (95%CI 0.98-1.65) of experiencing in-hospital postoperative infection, 54.6% higher odds (95%CI 1.35-1.77) of experiencing in-hospital postoperative gastrointestinal complications, and 70.9% higher odds (95%CI 1.48-1.97) of experiencing in-hospital postoperative genitourinary complications as compared to patients with BMI less than 30.

Conclusion: Patients with class III obesity undergoing operative intervention for colonic diverticular disease are at increased risk of short-term postoperative morbidity as compared to patients with BMIs under 30.