Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Intra-abdominal abscess in adults
Systematic review	4468 adults having an appendicectomy with either simple appendicitis or complicated appendicitis 10 RCTs in this analysis	Proportion of people with intra-abdominal abscess post surgery 16/2211 (1%) with surgery plus perioperative systemic antibiotics 39/2257 (2%) with surgery alone	OR 0.35 95% CI 0.13 to 0.91	Moderate effect size	surgery plus antibiotics
Systematic review	2968 adults having an appendicectomy with simple appendicitis 8 RCTs in this analysis Subgroup analysis	Proportion of people with intra-abdominal abscess post surgery 9/1433 (0.6%) with surgery plus perioperative systemic antibiotics 22/1535 (1.4%) with surgery alone	OR 0.46 95% CI 0.23 to 0.94	Moderate effect size	surgery plus antibiotics
Systematic review	476 adults having an appendicectomy with complicated appendicitis 3 RCTs in this analysis Subgroup analysis	Proportion of people with intra-abdominal abscess post surgery 3/262 (1%) with surgery plus perioperative systemic antibiotics 4/205 (2%) with surgery alone	OR 0.54 95% CI 0.12 to 2.43		Not significant