Leopold SJ, Watson JA, Jeeyapant A, et al. – Using records from 9,040 hospitalized children (aged 0-12 years) and adults (aged 12-87 years), researchers developed a structural model causal interference approach to determine causal relationships between epidemiological, laboratory, and clinical variables in patients with severe falciparum malaria enrolled in clinical trials and their in-hospital mortality. Participants had severe falciparum malaria and were from 15 countries in Africa and Asia; they were prospectively studied over the past 35 years. They found that patients with lower hematocrits were at a lower risk of death and that there was no strong evidence for a beneficial effect of transfusion in moderately anemic children (15 to 25% hematocrit). Thus, in the context of severe falciparum malaria, moderate anemia may exert protective effects against mortality, and a conservative approach to blood transfusion might be warranted. The current hemoglobin threshold used to define severe malarial anemia (5 g/dL) may be too high and should be reconsidered, according to the investigators. They cautioned, however that further randomized studies are necessary to evaluate optimal transfusion thresholds.