[S073]-The impact of interval appendectomy timing on follow-up adverse outcomes

Objective: This study aims to compare the timing of interval appendectomy (IA) and its impact on post-operative outcomes. Methods: A retrospective analysis was performed for adult patients diagnosed with appendicitis between 2006 and 2017. IA was defined as a follow-up appendectomy > 1 week and < 2 years after the initial presentation. Time intervals were divided into 4 groups based on patient quartiles: 1–6 weeks, 7–9 weeks, 10–15 weeks, and > 15 weeks. The primary outcome measure was length of stay (LOS). Secondary outcomes included 30-day readmission and IA post-operative complications. Tertiary outcomes included 30-day mortality and colonoscopy suggesting neoplasm or Inflammatory Bowel Disease. Results: A total of 5069 patients’ records whose interval appendectomy fell > 1 week and < 2 years after initial presentation were analyzed. Among them, 1006 (19.85%) underwent an initial percutaneous abscess drainage at diagnosis. The median timing for IA was 9.2 weeks. Patients with IA at 1–6 weeks were more likely to have longer LOS when compared to 7–9 weeks (ratio 1.33, 95% CI 1.2–1.48) and 10–15 weeks (ratio 1.38, 95% CI 1.25–1.52). IA between 7 and 9 weeks (ratio 0.81, 95% CI 0.73–0.89) and 10–15 weeks (ratio 0.78, 95% CI 0.71–0.86) was associated with significantly shorter LOS compared to those receiving the operation after 15 weeks. Further, patients requiring abscess drainage (ratio 1.2, 95% CI 1.13–1.34) or those with comorbidities (ratio 1.51, 95% CI 1.39–1.63) were more likely to have longer LOS at IA. Socioeconomic and demographic differences including Black, Hispanic, and those with Medicare and Medicaid insurance had a greater LOS after their IA. Conclusion: LOS remains lowest among patients undergoing IA between 7–9 weeks and 10–15 weeks after initial appendicitis presentation. Patients with lower socioeconomic status or from racial minorities had a longer LOS after IA. Graphical abstract: [Figure not available: see fulltext.].