Baseline characteristics subgroup 1
| Variable | Preweighting sample | P value | Postweighting sample | P value | ||
| Laparoscopic appendectomy, n | Open appendectomy, n | Laparoscopic appendectomy, n | Open appendectomy, n | |||
| Age, n (%) | ||||||
| 0–5 | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| 6–11 | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| 12–17 | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Sex, n (%) | ||||||
| Female | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Male | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| BMI | Mean (SD) | Mean (SD) | p=0.XX | Mean (SD) | Mean (SD) | p=0.XX |
| Comorbidities, n (%) | ||||||
| Abdominal surgery | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Abdominal (non-surgical) | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Cardiopulmonary | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Neurological | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Metabolical | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Nefro/urological | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Endocrinological | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Musculoskeletal | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Other | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| ASA score, n (%) | ||||||
| ASA I | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| ASA II | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| ASA III | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| ASA IV | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| ASA V | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Preoperative SIRS, n (%) | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Complex appendicitis prediction score | Mean (SD) | Mean (SD) | p=0.XX | Mean (SD) | Mean (SD) | p=0.XX |
| Preference for treatment strategy | ||||||
| Surgeon | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Parent(s) | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Patient | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Preoperative imaging, n (%) | ||||||
| US | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| US+MRI | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| US+CT | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Hospital, n (%) | ||||||
| Academic | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Teaching | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Non-teaching | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Daytime presentation, n (%) | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Weekend presentation, n (%) | N (% of total) | N (% of total) | p=0.XX | N (% of total) | N (% of total) | p=0.XX |
| Duration of abdominal pain | Median (IQR) | Median (IQR) | p=0.XX | Median (IQR) | Median (IQR) | p=0.XX |
ASA, American Society of Anesthesiologists; BMI, Body Mass Index; SIRS, Systemic Inflammatory Response Syndrome.