Potential bias	Authors' judgement
Random sequence generation (selection bias)	High – not randomized or quasi‐randomized Unclear – randomized stated, but method not reported Low – described method of randomization
Allocation concealment (selection bias)	High – not concealed, open‐label trial for individually randomized or method of concealment not adequate Unclear – details of method not reported or insufficient details Low – central allocation, sequentially numbered opaque sealed envelopes
Blinding (performance bias and detection bias)	High – personnel, participants, or outcome assessors not blinded Unclear – no details or insufficient details reported Low – personnel, participants, and outcome assessors blinded
Incomplete outcome data (attrition bias)	High – losses to follow‐up not evenly distributed across intervention and control group, high attrition rate (≥ 20% for the main outcome) Unclear – no details reported, insufficient details reported Low – no losses to follow‐up, losses < 20% and evenly distributed across groups, intention‐to‐treat analysis used Note: for cluster randomized controlled trials, the loss relates to the clusters
Selective reporting (reporting bias)	High – did not fully report measured or relevant outcomes Unclear – insufficient information reported to judge Low – all expected outcomes were reported
Other bias	Low – no obvious other source of bias of concern to review authors High – major source of bias such as unexplained differences in baseline characteristics