BUN as a risk factor for mortality after coronary artery bypass grafting. Commentary

Background. Although information on blood urea nitrogen (BUN) is universally available for patients who undergo coronary artery bypass grafting, BUN has not often been considered as a risk factor for mortality. This study assessed BUN as a risk factor for CABG patients. Methods. Four data sets were evaluated that differed with respect to the types of patients and available patient information. In each of these data sets logistic regression analysis was used to examine the relationship between BUN and mortality after adjusting for other risk factors. Results. Blood urea nitrogen level was strongly associated with mortality in each of the data sets. After adjustment for the available risk factors other than creatinine level, patients with BUN levels greater than 30 mg/dL had a relative odds of mortality ranging between 1.86 and 2.49 (p < 0.0001 in three of the data sets). Even after adjustment for creatinine level as well as the other variables, BUN was statistically significant at the p less than 0.01 level for three of the data sets. Conclusions. The results suggest that BUN provides additional information on cardiac function that supplements the information provided by other risk factors.