Clinical outcomes in patients with complicated appendicitis

Complicated appendicitis (appendicitis with abscess, perforation, or generalized peritonitis) poses a significant burden on healthcare systems, with incidence up to 28-29%. Current management options include antibiotic therapy and up-front surgery, antibiotic therapy and percutaneous drainage, or antibiotic therapy alone. There is no consensus on treatment guidelines in current literature. This study aims to better define treatment algorithms for patients presenting with acute complicated appendicitis by evaluating clinical outcomes in those treated with or without surgery.

We performed a single-institution, retrospective review of 220 adult patients (≥ 18 years old) treated for acute complicated appendicitis from January 2017 to June 2022. Demographic and clinicopathologic variables were collected and analyzed. We compared patients who were managed non-operatively versus operatively. Regression modeling was used to determine factors associated with non-operative management (NOM) and those predictive of failure of NOM.

Our analysis showed 26.3% patients with acute complicated appendicitis underwent NOM (n = 58), versus 73.6% underwent operative management at index admission (n = 162). Within the NOM group, 55.1% patients were treated with antibiotics alone (n = 32) versus 44.8% with percutaneous drainage (n = 26). Within the operative cohort, 88.7% of patients underwent appendectomy (n = 142). Age, body mass index, comorbidities, vital signs and laboratory values on admission were similar between both groups. Clinical factors predictive of initial NOM were perforation (OR 7.9, 95% CI 3.7-16.5) and phlegmon (OR 6.3, 95% CI 2.8-14.1) at presentation. Clinical factors predictive of failure of NOM requiring surgery on index admission or within 30 days was larger abscess and/or phlegmon size (OR 1.76, 95% CI 1.0-3.0).

There may be a role in identifying clinical factors in patients with complicated appendicitis that favor non operative versus operative management. Larger abscess and/or phlegmon size could be a predictor of failure of NOM.