Link to the paper: https://www.nejm.org/doi/full/10.1056/NEJMoa1900105
The World Health Organization, WHO, has specific guidelines for transfusion in African countries due to the scarcity of blood products. Patients with extreme anemia do not necessarily receive transfusion unless fitting specific guidelines. The WHO guideline cutoff values are substantially less than values used in other areas of the world. This study suspected that patients coming in with extreme anemia should be transfused immediately which would lead to decreased mortality as opposed to the current guidelines where transfusion is held off unless symptoms of distress occur. The study was performed in Africa and the primary outcome they were looking for was mortality. The study found there were no differences in mortality between patients with extreme anemia who were transfused immediately and patients with extreme anemia who were only transfused with symptoms. However, those who were not immediately transfused had a longer hospital stay.