The TRIGGER trial
thromboembolic, bleeding, Gastrointestinal Bleeding
BLEEDING, HAND INFECTION, GASTROINTESTINAL BLEEDING, EVENTS, ACUTE UPPER GASTROINTESTINAL BLEEDING, TRANSFUSION REACTIONS
Transfusion in Gastrointestinal Bleeding Trial (TRIGGER) was a CRT that compared two different thresholds for red blood cell transfusion (restrictive threshold versus liberal threshold) in patients with acute upper gastrointestinal bleeding.We re-analysed clinical outcome and adherence measures to compare to what extent estimates for the participant- and cluster-average effects differed. If estimates for the two effects differ, this may imply the presence of informative cluster size, which means that choosing an inappropriate estimator (i.e. one that targets the wrong estimand, or that relies on the assumption of no informative cluster size) could lead to bias.We analysed 17 outcomes in total. Binary outcomes were further bleeding, thromboembolic or ischaemic events, and infection (each measured both in-hospital and up to day 28), as well as mortality, acute transfusion reactions, surgery/radiology, therapeutic endoscopy, whether the patient received at least one red blood cell transfusion, and full adherence to protocol (each measured in-hospital only). Continuous outcomes were the number of days spent in hospital, the number of red blood cell transfusions, average adherence (the percentage of Hb readings where the protocol was correctly followed), the EQ-5D score and the EuroQol-5D Visual Analogue Scale (EQ-5D VAS) score.We initially planned to analyse mortality both in-hospital and at day 28, but found that results were identical between the two, and so only report in-hospital results.