LAUSR

N 122 62 Age in years (range) 21⋅9 (2-69) 27⋅1 (4 – 66) 0⋅0066 Number<16 years (%) 55 (45) 21 (34) 0⋅0572 Number≥16 years (%) 67 (55) 41 (66) Female (%) 67 (54⋅9) 37 (51⋅3) 0⋅7473 Abdominal imaging (%) 81 (66⋅4) 54 (87⋅1) 0⋅0067 US (%) 62 (50⋅8) 26 (41⋅9) 0⋅0447 CT (%) 21 (17⋅2) 34 (54⋅8) 0⋅0001 US confirmed appendicitis (%) 7/62 (11⋅3) 9/26 (34⋅6) 0⋅0143 Secondary findings on US (%) 30/62 (48⋅4) 14/26 (50) 0⋅8156 CT-confirmed appendicitis (%) 19/21 (90⋅5) 27/34 (79⋅4) 0⋅4568 Complicated appendicitis on CT (%) 3/21 (14⋅3) 11/34 (32⋅4) 0⋅2046 SARS-CoV-2 swab* (%) 1 (0⋅8) 23 (37⋅1) Positive result (%) 0 1/23 (4⋅4) Operative intervention (%) 107 (87⋅7) 34 (54⋅8) 0⋅0001 Laparoscopic (%) 88/107 (82⋅2) 7/34 (20⋅6) 0⋅0001 Open (%) 19/107 (17⋅8) 27/34 (79⋅4) <16 years (%) 17/53 (32⋅1) 16/18 (88⋅9) 0⋅0001 >16 years (%) 2/54 (3⋅7) 11/16 (68⋅8) 0⋅0001 Non-operative management (%) 15/122 (12⋅29%) 28/62 (45⋅16%) 0⋅0001 Imaging performed 14/15 (93⋅33%) 21/22 (95⋅45%) US performed 13/15 (86⋅67%) 9/22 (40⋅91%) CT performed 1/15 (6⋅67%) 16/22 (72⋅73%) Imaging confirmed 0/15 (0%) 18/22 (81⋅67%) Complicated on imaging 0/15 (0%) 3/22 (13⋅67%) Alternative diagnosis at discharge** (%) 15/15 (100%) 6/28 (9⋅67%) UTI 5 0 Gynecological 1 3 Non-specific abdominal pain 9 3 Length of stay (median) 3 days 4 days 0⋅0001 Negative appendicectomy rate (%) 36/107 (33⋅64%) 0/34 (0%) 0⋅0001 Complicated appendicitis on histopathology 11/107 (10⋅28%) 13/34 (38⋅23%) 0⋅0004 Re-admission rate 2/122 (1⋅64%) 9/62 (14⋅52%) 0⋅0004 Post-operative 1/107 (0⋅93%) 2/34 (5⋅88%) 0⋅1443 Non-operative 1/15 (6⋅67%) 7/28 (25%) 0⋅2261 Conservatively managed appendicitis on discharge 6/22 (27⋅27%) Median time to readmission 7 days 9 days