Validation of the American Association for the Surgery of Trauma emergency general surgery score for acute appendicitis - An EAST multicenter study

BACKGROUND The American Association for the Surgery of Trauma (AAST) has proposed a grading system for anatomic severity of 16 Emergency General Surgery conditions, including appendicitis. This is the first prospective, multicenter clinical study evaluating the AAST Appendicitis grading scale. METHODS The EAST Appendicitis study utilized data collected prospectively from 27 centers, between January 2017 to June 2018. An overall grade was assigned as the highest grade of the subscales: clinical, radiographic, operative, and pathologic. Grade 1-3 of the clinical subscale was assigned as Grade 1. Patients with a final diagnosis other than appendicitis were excluded. The cohort was divided into two groups: simple appendicitis (Grades 1 and 2), and complicated appendicitis (Grades 3, 4, and 5). Fisher's exact and Kruskal-Wallis tests were used to determine association between the overall AAST grade and the following outcomes: infectious complications, Clavien-Dindo complications, hospital length of stay (LOS), 30-day emergency department visits, readmissions, and secondary interventions. RESULTS A total of 2,909 cases were analyzed: 1,656 (57%) were Grade 1; 181 (6%), Grade 2; 399 (14%) Grade 4; and 549 (19%) Grade 5; 94% of patients underwent appendectomy. Index hospitalization LOS increased significantly with increasing grade: 1, [1,1], 1 [1,2], 1 [1,2], 2 [1,3], and 32,5 (p < 0.001). Infectious complications, Clavien-Dindo complications, hospital LOS, and secondary interventions were significantly associated with increasing AAST severity grade during index hospitalization. For 30-day outcomes, similar trends were noted for readmission, 30-day infections complications, 30-day cumulative infectious complications, 30-day Clavien-Dindo complications, 30-day cumulative Clavien-Dindo complications, 30-day secondary interventions, and 30-day cumulative secondary interventions. CONCLUSION The AAST emergency general surgery grade for appendicitis is a valid predictor of clinical outcomes such as infectious complications, overall complications, and the need for secondary intervention. LEVEL OF EVIDENCE Prognostic, level III.