Randomised controlled trials (RCTs) that compared proton pump inhibitors (PPI) and histamine-2 receptor antagonists (H2RA) in critically ill adult patients with either of two risk factors (mechanical ventilation for more than 48 hours or coagulopathy) were eligible for inclusion. The primary outcome was clinically important bleeding. The secondary outcome was nosocomial pneumonia. Studies were excluded if there was a history of aspirin or non-steroidal anti-inflammatory drug (NSAID) use, active gastrointestinal bleeding or post-endoscopic treatment, or if there was no relevant outcome. Follow up was until discharge or death in all the included studies.
The intervention in all of the included RCTs was 40mg omeprazole per day given orally, intravenously or via a nasogastric tube. For one study the dose was doubled on the first day. The drugs used for comparison were ranitidine, famotidine or cimetidine. Details of the dosage and frequency of the specific drugs used were given in the review. All of the included patients were intensive care unit patients, most of whom required mechanical ventilation for 48 or more hours. No details were provided of the age or sex of the patients in the included studies. Details of the underlying diseases in all the included patients were provided. The incidence of clinically important bleeding and nosocomial pneumonia were measured in all the included RCTs.
The authors stated neither how papers were selected for the review nor how many reviewers performed the selection.