This is a retrospective observational study with its main aim of evaluating possible factors associated with complicated appendicitis. Current literature supports time from symptom onset until registration as the main and maybe only determinant of the outcome if patients are operated on within 24 hours. We wish to evaluate whether this is true in all patients, or there are subgroups in which time from registration to operation is associated with complicated appendicitis.

The data to be analyzed is that of patients operated on acutely for suspected appendicitis within 10 years in one medical center. Patients undergoing interval or incidental appendectomies will not be included. The endpoint to be evaluated is complicated appendicitis (gangrenous, abscess, perforated). The independent variables will include mainly sex, age, patient time (time from symptom onset to registration), hospital time (time from registration to operation), and missed diagnosis.

Inclusion Criteria:

• male and female patients of all ages who underwent appendectomy of acute appendicitis in a single medical center between December 1, 2006, and December 31, 2016

Exclusion Criteria:

• interval appendectomy,
• incidental appendectomy,
• appendectomy after failed antibiotic treatment for either acute appendicitis or peri-appendicular abscess
• patients with a non-inflamed appendix
• those in whom symptom onset before hospitalization was not noted.

Patients operated in one medical center during one decade.

De-identified data will be made available upon reasonable request