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

Abstract

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.