Robustness of Randomized Trials Comparing Operative and Non-Operative Management of Acute Uncomplicated Appendicitis: A Fragility Analysis

Background The fragility index (FI) is a statistical evaluation of the robustness of randomized controlled trials (RCTs) and quantifies how many patient outcomes would need to change to alter statistical significance. A FI of ≤3 is considered a fragile study. This study assessed the fragility of RCTs comparing non-operative management (NOM) and operative management (OM) of acute uncomplicated appendicitis (AUA). Methods A systematic search of PubMed and Google Scholar was conducted to identify RCTs published between January 2000 and September 2025 that reported a statistically significant dichotomous primary outcome ( P < 0.05) and featured 2 parallel arms (NOM vs OM). The FI, reverse FI (RFI), fragility quotient (FQ), and reverse FQ (RFQ) were calculated. Results Five RCTs met criteria for inclusion: 4 negative non-inferiority (NI) RCTs and 1 positive superiority RCT. The superiority RCT assessed treatment success at 6 months and found OM to be superior (FI = 10, FQ = 0.056). For negative NI RCTs, median (range) RFI scores were 30 (4-55); none of these trials confirmed NI. The median RFQ scores were 0.050 (0.017-0.189). The NI RCT with the highest RFI (RFI = 55, RFQ = 0.065) analyzed treatment at 12 months, and the absolute difference in failure rates was 26.7% (90% CI: 22.4-30.9), failing to demonstrate non-inferiority of antibiotic management. Discussion All examined RCTs were robust, favoring OM as the standard of care for AUA. Fragility calculations can help interpret the quality of RCTs, supplementing traditional statistical calculations and providing an additional metric for readers to assess study robustness.