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. 2023 Feb 7;2023(2):CD014909. doi: 10.1002/14651858.CD014909.pub2

Risk of bias for analysis 2.1 SSI.

Study Bias
Randomisation process Deviations from intended interventions Missing outcome data Measurement of the outcome Selection of the reported results Overall
Authors' judgement Support for judgement Authors' judgement Support for judgement Authors' judgement Support for judgement Authors' judgement Support for judgement Authors' judgement Support for judgement Authors' judgement Support for judgement
Zmora 2003 Low risk of bias The generation of the randomisation sequence and the allocation concealment were appropriate. There was no baseline imbalance that would indicate a problem with randomisation. Low risk of bias Both participants and those delivering the intervention were aware of intervention received. There were no deviations from intervention. Low risk of bias 92% of the 415 randomised patients were analysed.
Twenty‐nine patients were excluded after randomization due to the intraoperative exclusion criteria (18 had abdominoperineal resection and
11 had a proximal stoma). Six patients withdrew their consent before surgery, leaving 380 patients for the data analysis. Low risk of bias The assessors were not blinded, but it is unlikely that knowledge of the intervention would have influenced the assessment, as the diagnosis was made using well‐defined criteria. Some concerns No pre‐registered method (registry or protocol) available. Some concerns Some concerns due to the lack of information about a predefined analysis plan.
Ram 2005 Low risk of bias The generation of the randomisation sequence and the allocation concealment were appropriate. There was no baseline imbalance that would indicate a problem with randomisation. Low risk of bias Both participants and those delivering the intervention were aware of intervention received. There were no deviations from intervention. Low risk of bias All participants were included in the analysis. Low risk of bias The assessors were not blinded, but it is unlikely that knowledge of the intervention would have influenced the rating, as the diagnosis was made using well‐defined criteria. Some concerns No pre‐registered method (registry or protocol) available. Some concerns Some concerns due to the lack of information about a predefined analysis plan.
Suzuki 2020 Low risk of bias The generation of the randomisation sequence and the allocation concealment were appropriate. There was no baseline imbalance that would indicate a problem with randomisation. Low risk of bias Both participants and those delivering the intervention were aware of intervention received. There were no deviations from intervention. Low risk of bias >95% of randomised patients were analysed. Low risk of bias The assessors were not blinded, but it is unlikely that knowledge of the intervention would have influenced the assessment, as SSIs are clearly defined clinically. Some concerns No pre‐registered method (registry or protocol) available. Some concerns Some concerns due to the lack of information about a predefined analysis plan.