Predictive Value of Blood Urea Nitrogen to Albumin Ratio in Long-Term Mortality in Intensive Care Unit Patients with Acute Myocardial Infarction: A Propensity Score Matching Analysis

Diming Zhao,1 Yilin Liu,2 Shanghao Chen,1 Zhenqiang Xu,3,4 Xiaomei Yang,5 Hechen Shen,1 Shijie Zhang,1 Yi Li,1 Haizhou Zhang,3,4 Chengwei Zou,3,4 Xiaochun Ma3,4 1Department of Cardiovascular Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250021, People’s Republic of China; 2Department of Ophthalmology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250021, People’s Republic of China; 3Department of Cardiovascular Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, 250021, People’s Republic of China; 4Department of Cardiovascular Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, People’s Republic of China; 5Department of Anesthesiology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, 250021, People’s Republic of ChinaCorrespondence: Xiaochun Ma, Tel +8615169196737, Email mxcmxc2008@163.comBackground: Blood urea nitrogen to albumin ratio (BAR) has been implicated in predicting outcomes of various inflammatory-related diseases. However, the predictive value of BAR in long-term mortality in patients with acute myocardial infarction (AMI) has not yet been evaluated.Methods: In this retrospective cohort study, the patients were recruited from the Medical Information Mart for Intensive Care III (MIMIC III) database and categorized into two groups by a cutoff value of BAR. Kaplan–Meier (K-M) analysis and Cox proportional hazard model were performed to determine the predictive value of BAR in long-term mortality following AMI. In order to adjust the baseline differences, a 1:1 propensity score matching (PSM) was carried out and the results were further validated.Results: A total of 1827 eligible patients were enrolled. The optimal cutoff value of BAR for four-year mortality was 7.83 mg/g. Patients in the high BAR group tended to have a longer intensive care unit (ICU) stay and a higher rate of one-, two-, three- and four-year mortality (all p< 0.001) compared with those in the low BAR group. K-M curves indicated a significant difference in four-year survival (p< 0.001) between low and high BAR groups. The Cox proportional hazards model showed that higher BAR (> 7.83) was independently associated with increased four-year mortality in the entire cohort, with a hazard ratio (HR) of 1.478 [95% CI (1.254– 1.740), p< 0.001]. After PSM, the baseline characteristics of 312 pairs of patients in the high and low BAR groups were well balanced, and similar results were observed in K-M curve (p=0.003).Conclusion: A higher BAR (> 7.83) was associated with four-year mortality in patients with AMI. As an easily available biomarker, BAR can predict the long-term mortality in AMI patients independently.Keywords: acute myocardial infarction, blood urea nitrogen, albumin, long-term mortality, MIMIC III database