Restrictive vs liberal red blood cell transfusion strategies in patients with acute myocardial infarction and anemia: Rationale and design of the REALITY trial

Background Anemia is common in patients with acute myocardial infarction (AMI), and is an independent predictor of mortality. The optimal transfusion strategy in these patients is unclear. Hypothesis We hypothesized that a "restrictive" transfusion strategy (triggered by hemoglobin ≤8 g/dL) is clinically noninferior to a "liberal" transfusion strategy (triggered by hemoglobin ≤10 g/dL), but is less costly. Methods REALITY is an international, randomized, multicenter, open-label trial comparing a restrictive vs a liberal transfusion strategy in patients with AMI and anemia. The primary outcome is the incremental cost-effectiveness ratio (ICER) at 30 days, using the primary composite clinical outcome of major adverse cardiovascular events (MACE; comprising all-cause death, nonfatal stroke, nonfatal recurrent myocardial infarction, or emergency revascularization prompted by ischemia) as the effectiveness criterion. Secondary outcomes include the ICER at 1 year, and MACE (and its components) at 30 days and at 1 year. Results The trial aimed to enroll 630 patients. Based on estimated event rates of 11% in the restrictive group and 15% in the liberal group, this number will provide 80% power to demonstrate clinical noninferiority of the restrictive group, with a noninferiority margin corresponding to a relative risk equal to 1.25. The sample size will also provide 80% power to show the cost-effectiveness of the restrictive strategy at a threshold of €50 000 per quality-adjusted life year. Conclusions REALITY will provide important guidance on the management of patients with AMI and anemia.