Background: Association between time-to-appendectomy and clinical outcomes is controversial with conflicting data regarding risk of perforation. The purpose of this study was to explore the associations between in-hospital delay in treatment of simple appendicitis with the incidence of complicated appendicitis discovered at appendectomy. Methods: The Eastern Association for the Surgery of Trauma (EAST) Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous (MUSTANG) database was queried and patients with acute appendicitis diagnosed on imaging were included. Upgrade was defined as gangrenous or perforated finding at appendectomy. Time intervals from emergency department (ED) triage to appendectomy were recorded in six-hour groups. Upgrade percentage for each group was presented and rates of a composite end point (30-day incidence of surgical site infection, abscess, wound complication, Clavien-Dindo complication, secondary intervention, ED visit, hospital re-admission, and mortality) were compared with Bonferroni correction to determine statistical significance (p = 0.05/9 = 0.005). Results: Of 3,004 included subjects, 484 (16%) experienced upgrade at appendectomy. Upgrade rates (%, 95% confidence interval [CI]) were: group 0-6 hours, 17% (95% CI, 14-19); group 6-11 hours, 15% (95% CI, 13-17%); group 12-17 hours, 16% (95% CI, 13-19); group 18-23 hours, 17% (95% CI, 12-23); group 24-29 hours, 30% (95% CI, 20-43); and group 30+ hours, 24% (95% CI, 14-37) (p = 0.014, NS by Bonferroni). Of 484 subjects with upgrade, 200 (41%; 95% CI, 37-46) had a worse composite outcome compared with 518 (21%; CI, 19-22) of 2,520 subjects with no upgrade (p < 0.001). The upgrade group was older (49 ± 17 years vs 39 ± 16 years), had a higher Charlson comorbidity index (CCI; 1.6 ± 1.9 vs 0.7 ± 1.4) and was more likely to have positive smoking history (20% vs 14%), and prior surgery (30% vs 22%; p < 0.001). Conclusions: We propose that ≥24-hour delay from ED triage to appendectomy is not associated with increased rate of severity upgrade from simple to complicated appendicitis. When upgrade occurs, it is correlated with older age, higher CCI, smoking history, and prior surgery and is associated with worse clinical outcomes.

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