Siddique 2015.

Methods	RCT Methods to control for contributory patient factors: none
Participants	Age: Group 1 (mean): 36 Group 2 (mean): 36 Gender: not reported Types of incisions: all participants had a midline incision Types of surgery: both elective and emergent (proportions not reported) Contamination classification of included participants: not described Preoperative antibiotic use: "all patients received antibiotics against gram negative and anaerobic organisms" Prognostic patient factors: not reported in detail Inclusion criteria: patients undergoing a midline laparotomy, age > 15, ASA 1 & 2 Exclusion criteria: patients who developed a wound infection
Interventions	Comparisons reported: Group 1: Sutures: PDS (monofilament, slowly absorbable) Suture technique: continuous Closure method: mass Group 2: Sutures: polypropylene (monofilament, non‐absorbable) Suture technique: continuous Closure method: mass Characteristics of surgeons: not reported
Outcomes	Dehiscence: not defined, diagnosed within 7 days of surgery
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants accounted for, no losses to follow‐up
Selective reporting (reporting bias)	Low risk	There was no evidence of selective reporting
Other bias	High risk	Participants were excluded if they developed a wound infection