A high-dose 24-hour tranexamic acid infusion for the treatment of significant gastrointestinal bleeding: HALT-IT RCT
Authors: Roberts Ian , Shakur-Still Haleema , Afolabi Adefemi , Akere Adegboyega , Arribas Monica , Austin Emma , Bal Kiran , Bazeer Nuha , Beaumont Danielle , Brenner Amy , Carrington Laura , Chaudhri Rizwana , Coats Timothy , Gilmore Ian , Halligan Kenneth , Hussain Irshad , Jairath Vipul , Javaid Kiran , Kayani Aasia , Lisman Ton , Mansukhani Raoul , Miners Alec , Mutti Muttiullah , Nadeem Muhammad Arif , Pollok Richard , Prowse Danielle , Simmons Jonathan , Stanworth Simon , Veitch Andrew , Williams Jack 
Published: October 2021

Background
Tranexamic acid reduces blood loss in surgery and the risk of death in trauma patients. Meta-analyses of small trials suggest that tranexamic acid decreases the number of deaths from gastrointestinal bleeding, but these meta-analyses are prone to selection bias.

Objective
The trial provides reliable evidence of the effect of tranexamic acid on mortality, rebleeding and complications in significant acute gastrointestinal bleeding.

Design
A multicentre, randomised, placebo-controlled trial and economic analysis. Patients were assigned by selecting one treatment pack from a box of eight, which were identical apart from the pack number. Patients, caregivers and outcome assessors were masked to allocation. The main analyses were by intention to treat.

Setting
The setting was 164 hospitals in 15 countries, co-ordinated from the London School of Hygiene & Tropical Medicine.

Participants
Adults with significant upper or lower gastrointestinal bleeding (n = 12,009) were eligible if the responsible clinician was substantially uncertain about whether or not to use tranexamic acid. The clinical diagnosis of significant bleeding implied a risk of bleeding to death, including hypotension, tachycardia or signs of shock, or urgent transfusion, endoscopy or surgery.

Intervention
Tranexamic acid (a 1-g loading dose over 10 minutes, then a 3-g maintenance dose over 24 hours) or matching placebo.

Main outcome measures
The primary outcome was death due to bleeding within 5 days of randomisation. Secondary outcomes were all-cause and cause-specific mortality; rebleeding; need for endoscopy, surgery or radiological intervention; blood product transfusion; complications; disability; and days spent in intensive care or a high-dependency unit.

Results
A total of 12,009 patients were allocated to receive tranexamic acid (n = 5994, 49.9%) or the matching placebo (n = 6015, 50.1%), of whom 11,952 (99.5%) received the first dose. Death due to bleeding within 5 days of randomisation occurred in 222 (3.7%) patients in the tranexamic acid group and in 226 (3.8%) patients in the placebo group (risk ratio 0.99, 95% confidence interval 0.82 to 1.18). Thromboembolic events occurred in 86 (1.4%) patients in the tranexamic acid group and 72 (1.2%) patients in the placebo group (risk ratio 1.20, 95% confidence interval 0.88 to 1.64). The risk of arterial thromboembolic events (myocardial infarction or stroke) was similar in both groups (0.7% in the tranexamic acid group vs. 0.8% in the placebo group; risk ratio 0.92, 95% confidence interval 0.60 to 1.39), but the risk of venous thromboembolic events (deep-vein thrombosis or pulmonary embolism) was higher in tranexamic acid-treated patients than in placebo-treated patients (0.8% vs. 0.4%; risk ratio 1.85, 95% confidence interval 1.15 to 2.98). Seizures occurred in 38 patients who received tranexamic acid and in 22 patients who received placebo (0.6% vs. 0.4%, respectively; risk ratio 1.73, 95% confidence interval 1.03 to 2.93). In the base-case economic analysis, tranexamic acid was not cost-effective and resulted in slightly poorer health outcomes than no tranexamic acid.

Conclusions
Tranexamic acid did not reduce death from gastrointestinal bleeding and, although inexpensive, it is not cost-effective in adults with acute gastrointestinal bleeding.

Future work
These results caution against a uniform approach to the management of patients with major haemorrhage and highlight the need for randomised trials targeted at specific pathophysiological processes.

Limitations
Although this is one of the largest randomised trials in gastrointestinal bleeding, we cannot rule out a modest increase or decrease in death due to bleeding with tranexamic acid.

Trial registration
Current Controlled Trials ISRCTN11225767, ClinicalTrials.gov NCT01658124 and EudraCT 2012-003192-19.

Funding
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 58. See the NIHR Journals Library website for further project information.