Due to the high mortality and spread rates of coronavirus disease 2019 (COVID-19), there are currently serious challenges in emergency department management. As such, we investigated whether the blood urea nitrogen (BUN)/albumin ratio (BAR) predicts mortality in the COVID-19 patients in the emergency department.

A total of 602 COVID-19 patients who were brought to the emergency department within the period from March to September 2020 were included in the study. The BUN level, albumin level, BAR, age, gender, and in-hospital mortality status of the patients were recorded. The patients were grouped by in-hospital mortality. Statistical comparison was conducted between the groups.

Of the patients who were included in the study, 312(51.8%) were male, and their median age was 63 years (49–73). There was in-hospital mortality in 96(15.9%) patients. The median BUN and BAR values of the patients in the non-survivor group were significantly higher than those in the survivor group (BUN: 24.76 [17.38–38.31] and 14.43 [10.84–20.42], respectively [p < 0.001]; BAR: 6.7 [4.7–10.1] and 3.4 [2.5–5.2], respectively [p < 0.001]). The mean albumin value in the non-survivor group was significantly lower than that in the survivor group (3.60 ± 0.58 and 4.13 ± 0.51, respectively; p < 0.001). The area-under-the-curve (AUC) and odds ratio values obtained by BAR to predict in-hospital COVID-19 mortality were higher than the values obtained by BUN and albumin (AUC of BAR, BUN, and albumin: 0.809, 0.771, and 0.765, respectively; odds ratio of BAR>3.9, BUN>16.05, and albumin<4.01: 10.448, 7.048, and 6.482, respectively).

The BUN, albumin, and BAR levels were found to be reliable predictors of in-hospital mortality in COVID-19 patients, but BAR was found to be a more reliable predictor than the BUN and albumin levels.