Acute appendicitis before, during, and after the COVID-19 pandemic: a population-based cohort study

Background Acute appendicitis remains a common surgical emergency. The COVID-19 pandemic severely impacted all the health systems globally including surgical emergencies management. This study aimed to assess changes in diagnosis and treatment of acute appendicitis in a tertiary emergency hospital serving an urban population before, during, and after the COVID-19 years. Methods This was a population-based cohort study including consecutive ≥ 18-year-old residents of a metropolitan area presenting with acute appendicitis at the tertiary emergency hospital. The study period between January 2018 and December 2023 was divided into: 2018-2019 (pre-COVID-19); 2020-2021 (COVID-19); 2022-2023 (post-COVID-19). Comparisons among the three periods were performed using one-way ANOVA and the Chi-square or Fisher's exact test as appropriate. Results The breakdown of 1,721 patients included was: 662 in 2018-2019, 422 in 2020-2021, and 637 in 2022-2023. Although the catchment area population (1,817 vs. 1,799 vs. 1,781 MM; p  = 0.2), 27 surgeons (27 vs. 27 vs. 27), and 107,202 CT scans (32,048 vs. 38,806 vs. 36,348; p  = 0.716) were stable, colonoscopies significantly decreased in 2020-2021 (4,588 vs. 2,457 vs. 4,204; p  = 0.012). The number of patients presenting with acute appendicitis decreased during the pandemic, with a relative increase in complicated cases. However, complication and mortality rates did not differ. The postoperative length of stay did not change significantly, despite the increased laparoscopic access rates. The appendiceal neoplasm rates were 2.4% in the COVID-19 and 1.9% in the post-COVID-19 year groups. Conclusions This six-year population-based study found a decreased number of patients presenting with acute appendicitis during the pandemic years, with a relative increase in complicated cases but no difference in mortality rates. The rates of appendiceal neoplasms raise concerns regarding the offering of conservative treatment.