PM1067: Postoperative Antibiotics for Complicated Appendicitis in Children: Piperacillin/tazobactam versus Ceftriaxone with Metronidazole

Background: Recent studies are discordant regarding postoperative use of piperacillin/tazobactam (PT) versus ceftriaxone plus metronidazole (CM) for complicated appendicitis. Some argue that the broader spectrum antibiotic PT decreases intraabdominal abscess formation and percutaneous drainage rates; however, antibiotic stewardship, and once-a-day dosing favor CM. We aim to compare outcomes of postoperative antibiotic utilization using a large administrative database.

Methods: We queried the Pediatric Health Information System for patients 2-18 years old who underwent laparoscopic appendectomy between 2016-2021. Patients with ICD10 codes of complicated appendicitis who received at least 2 days of inpatient IV antibiotics postoperatively were included. Patients were then grouped into whether they received PT, CM, or other during the first two postoperative days. The trend of antibiotic usage over the years, 30-day post operative imaging use, cost, and adverse outcomes defined as the rates of ED revisits, readmissions, and abscess drainage were evaluated.

Results: A total of 31,539 children from 46 tertiary pediatric hospitals were included. Median age was 10 years [IQR 7-13]. 29.2% received PT, 54.5% received CM, and 16.3% received a different antibiotic other than CM or PT with wide variation among the included hospitals (Figure). The use of PT demonstrated a decreasing trend over the years from 37.4% in 2016 to 26.8% in 2021 with a reciprocal increase in CM. Table1 demonstrated the unadjusted outcomes for each of the groups. In multivariable logistic regression analysis with clustering to account for inter-hospital variation, PT was associated with higher odds of hospital and ED revisits (OR1.34 [95%CI 1.14-1.56]), hospital readmissions (OR1.55 [95%CI 1.27-1.89]), intraabdominal abscess formation (OR1.49 [95%CI 1.22-1.82]), and percutaneous abscess drainage (OR1.33 [95%CI 1.02-1.72]) compared to the CM group. The other antibiotics group was associated with lower postoperative imaging use (OR 0.67 [95%CI 0.54-0.83]) but did not demonstrate a statistically significant difference compared to the CM group in any of the other reported outcomes. The cost of the index hospitalization was not statistically significant between the groups.

Conclusion: In this nationwide sample, postoperative use of the antipseudomonal antibiotic piperacillin/tazobactam for complicated appendicitis is associated with higher rates of revisits, readmissions, and intraabdominal abscess when compared to combination ceftriaxone with metronidazole. Practice patterns appear to vary widely, suggesting that large analyses such as this are needed for generalizable results. These findings add to the growing contemporary literature directly comparing these two regimens.