The goal of this study was to establish a universal core outcome set (COS) for the measurement and reporting of outcomes associated with the treatment of pediatric acute uncomplicated appendicitis in randomized controlled trials. A previous systematic evaluation suggested the necessity for a COS that found 115 outcomes across 60 trials and systematic reviews of therapies for pediatric appendicitis. A total of 4 stages were involved in the development process: a systematic review to identify all previously reported outcomes; a 2-stage international Delphi study in which parents with their children and surgeons rated these outcomes for inclusion in the COS; focus groups with young people to identify missing outcomes; and international expert meetings to ratify the final COS. 

Using the results of the systematic review, researchers were able to map 129 outcomes into 43 distinct outcome words for the Delphi survey. By the 2nd round, there was agreement on 10 outcomes among the original 137 parents from 8 countries and 245 surgeons from 10 countries (61% and 85%, respectively). Death, bowel obstruction, intraabdominal abscess, recurrent appendicitis, complicated appendicitis, return to baseline health, readmission, reoperation, unplanned appendectomy, adverse events related to treatment, major and minor complications, and focus groups with 2 young people all contributed to the final COS (12). 

Patient and parent input was integral to the development of this evidence-based COS. To minimize inconsistencies in study results, aid in data synthesis, and make more well-informed decisions, this COS is recommended for all future studies assessing pediatric uncomplicated appendicitis treatment.