Hsiao 2000.

Methods	RCT Methods to control for contributory patient factors: none
Participants	Age: Group 1 (mean): 60.9 years Group 2 (mean): 58.5 years Gender: Group 1: 44% female Group 2: 48% female Type of incision: Group 1: midline 50.5%, paramedian 4.3%, subcostal 26.1%, subcostal plus midline 4.9%, bilateral subcostal plus midline 14.1% Group 2: midline 45.5%, paramedian 5.1%, subcostal 26.3%, subcostal plus midline 5.1%, bilateral subcostal plus midline 17.9% Type of surgery: all surgeries were elective Group 1: upper GI 17.4%, hepato‐pancreaticobiliary 63.6%, lower GI 15.2%, vascular 3.3%, other 0.5% Group 2: upper GI 15.4%, hepato‐pancreaticobiliary 65.4%, lower GI 13.5%, vascular 1.2%, other 4.5% Contamination classification of included participants: not described Pre‐operative antibiotic use: all participants received cefmetazole and metronidazole Prognostic patient factors: Group 1: mean BMI 23.0, malignancy 58.1% Group 2: mean BMI 22.8, malignancy 54.4% Inclusion criteria: patients undergoing elective laparotomy Exclusion criteria: emergency laparotomies, history of laparotomy within 3 months, previous incisional hernia
Interventions	Comparisons reported: Group 1 Suture: polyglactin‐910 (multifilament, fast absorbable) Suturing technique: continuous Closure method: mass Group 2: Suture: PDS (monofilament, slowly absorbable) Suturing technique: continuous Closure method: mass Surgeon characteristics: same surgeon for all procedures
Outcomes	Incisional hernia: visible and palpable defect in the fascia or a protrusion in the wound when the participant was carefully examined in both horizontal and vertical positions Follow‐up duration: 24 months Wound infection: purulent discharge from the wound, confirmed by standard signs including fever and an elevated leukocyte count Dehiscence: no definition provided Sinus or fistula: no definition provided
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Randomised based on last digit of hospital patient number
Allocation concealment (selection bias)	High risk	Randomised based on last digit of hospital patient number
Blinding (performance bias and detection bias) All outcomes	Low risk	Outcome assessor blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants accounted for and analysed
Selective reporting (reporting bias)	Low risk	Hernia (at least 1 year); dehiscence and wound infection outcomes all reported
Other bias	Low risk	The study appears to be free of other sources of bias