Potential Impact of Extended Postoperative Antibiotics on the Incidence of Surgical Site Infections after Diverticulitis Surgery: A Pilot Study

Abstract Background: Patients who undergo surgery for diverticulitis have high rates of postoperative surgical site infections (SSI). The Prediction and Enaction of Prevention Treatment Trigger (PREVENTT) Scale (Ann Surg) is used to identify patients at a high risk for SSI. Objectives: We hypothesized that patients with PREVENTT score ≥ 4 who receive antibiotics may have a lower SSI rate when compared to their predicted PREVENTT score rates. Design: Pilot study using prospectively collected institutional NSQIP data. Setting: Five hospitals including two academic ones that are part of a Colorectal Surgery Collaborative. Patients and Methods: Patients who underwent colectomy for diverticulitis between January 2016 and March 2020 were included in the study. Those with PREVENTT score ≥ 4 were considered for a 4-day course of postoperative antibiotics. Main Outcome Measure: The incidence of SSI in patients with PREVENTT score ≥ 4. Sample Size: A total of 572 patients underwent surgery for diverticulitis. Results: In all, 87 patients had PREVENTT score ≥ 4, and 34 of them (39.1%) were administered a 4-day course of postoperative antibiotics, with some surgeons also prescribing antibiotics to 70 of the remaining 485 patients (14.4%), who had lower PREVENTT scores. Patients who received antibiotics had overall more baseline comorbidities, including functional dependence (1.9% vs. 0, P = 0.003), ascites (0.96% vs. 0, P = 0.034), and renal failure (1.9% vs. 0.2%, P = 0.029). In addition, they were selected via PREVENTT to have had higher rates of open surgery, intra-operative abscesses, and longer surgeries ( P < 0.05). Only 4 of the 87 patients with PREVENTT ≥ 4 (4.6%) developed SSI. This rate was significantly lower than the predicted rate of PREVENTT score (4.6% vs. 35%, P < 0.001). Conclusion: The administration of preemptive postoperative antibiotics for 4 days after surgery significantly reduced the number of SSIs. Further research is needed to confidently argue in favor of a prolonged course of antibiotics; however, our results are encouraging and can help power future studies appropriately. Limitations: No randomization and lack of long-term follow-up data. Conflict of Interest: None to report.