 This study investigated the relationship between blood urea nitrogen, BUN, levels and clinical outcomes in patients with sepsis from two separate cohorts in the Czech Republic and the United States. The results showed that higher BUN levels were associated with increased risk of death within 28 days of hospitalization. Additionally, this association remained significant even when adjusted for potential confounding factors such as age, acute physiology and chronic health evaluation, Apache, SCORE, sequential organ failure assessment, SOFA, SCORE, estimated glomerular filtration rate, EGFR, and several other variables. These findings suggest that BUN levels may be useful in identifying patients who are at high risk of dying within 28 days of hospitalization due to sepsis. This article was authored by Martin Harism, Kaikwan Tan, Merrick Nallos, and others.