Unexpected complicated appendicitis in the elderly diagnosed with acute appendicitis.

Background: This study determined the prevalence of complicated appendicitis in elderly patients diagnosed preoperatively with uncomplicated appendicitis.

Methods: Patients with a preoperative diagnosis of uncomplicated appendicitis at an academic hospital from 11/2013 to 05/2017 were reviewed. Patients ≥65 years were compared to those younger. Pathology reports were categorized as either uncomplicated or complicated (COMP). The primary outcome was the prevalence of COMP appendicitis.

Results: The prevalence of COMP appendicitis increased with age after 20 years with an abrupt increase after 65 years. Patients ≥65 years were more likely to have COMP appendicitis (48.1% vs. 15.5%; OR: 5.1; p < 0.01) and prolonged stays (3.8 vs. 2.3 days; p < 0.01).

Conclusion: Nearly half of elderly patients had pathologic confirmation of complicated appendicitis despite no preoperative clinical or radiographic suspicion for complicated appendicitis. Nonoperative management of acute appendicitis in the elderly may not be appropriate due to the high rate of unexpected complicated appendicitis.