Hillman 2002.

Methods	Multi‐centre study Random allocation (sequence generation not specified) with sealed envelopes (not specified if opaque or not) No blind treatment Not strictly ITT: 91 participants excluded after randomisation because no aneurysm was found
Participants	People suffering from CT‐verified SAH within 48 hours prior to hospital admission Male:female ratio: 1.89 in both groups Age distribution similar in both groups Excluded: SAH > 48 hours, age < 15 years, pregnancy, and history of thromboembolic disease. People in whom no aneurysm was demonstrated on angiographic studies were excluded after randomisation
Interventions	Tranexamic acid (1 g iv immediately before transport, 1 g iv after 2 hours, and then 1 g every 6th hour until aneurysm occlusion up to 72 hours after SAH) versus control treatment
Outcomes	Outcome: Glasgow Outcome Scale at 6 months Events: rebleeding confirmed on CT or during operation until 72 hours after admission; clinically established delayed ischaemic neurological deficit at 6 months, not confirmed by imaging
Notes	Poor description of delayed ischaemic neurological deficit and how this was scored No mention of follow‐up for rebleeding after 72 hours
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Sequence generation was not described in the text
Allocation concealment (selection bias)	Unclear risk	Sealed envelopes were used that contained a randomisation document; however, it was not reported how these were ordered and if they were opaque or not
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel were not blinded (open study)
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described in the text
Incomplete outcome data (attrition bias) All outcomes	High risk	15% of included participants not evaluated in final analysis, which might have resulted in an overestimation of the effect estimate
Selective reporting (reporting bias)	Unclear risk	Previously published protocol was not mentioned, clinical outcome reported although not described in introduction or methods
Other bias	Low risk	None suspected based on study design and outcome