# Association between Blood Urea Nitrogen Level and In-Hospital Mortality in Patients with Acute Myocardial Infarction and Subsequent Gastrointestinal Bleeding

## TL;DR

Higher blood urea nitrogen levels are linked to increased risk of death in patients with heart attacks and later stomach bleeding.

## Contribution

This study identifies a BUN threshold (8.45 mmol/L) as a predictor of mortality in AMI patients with GIB.

## Key findings

- Non-survivors had significantly higher BUN levels than survivors (11.17 vs 8.09 mmol/L).
- A BUN cut-off of 8.45 mmol/L predicted mortality with an AUC of 0.678.
- Elevated BUN levels were associated with 4.01 times higher odds of in-hospital mortality.

## Abstract

Limited studies have explored the association between blood
urea nitrogen (BUN) levels and in-hospital mortality in patients with acute
myocardial infarction (AMI) and subsequent gastrointestinal bleeding (GIB). Our
objective was to explore this correlation.

276 individuals with
AMI and subsequent GIB were retrospectively included between January 2012 and
April 2023. The predictive value of BUN for in-hospital mortality was assessed
through receiver operating characteristic (ROC) curve. Logistic regression models
were constructed to assess the relationship between BUN and in-hospital
mortality. Propensity score weighting (PSW), sensitivity and subgroup analyses
were used to further explore the association.

Fifty-three
(19.2%) patients died in the hospital. BUN levels were higher in non-survivors
compared with the survivors [(11.17 ± 6.17) vs (8.09 ± 4.24),
p = 0.001]. The ROC curve suggested that the optimal cut-off for BUN
levels to predict in-hospital mortality was 8.45 mmol/L (AUC [area under the ROC
curve] 0.678, 95% confidence interval [CI] 0.595–0.761, p
< 0.001).
Multivariable logistic regression showed that elevated BUN levels (≥8.45
mmol/L) were positively association with in-hospital mortality (odds ratio [OR]
4.01, 95% CI 1.55–10.42, p = 0.004). After PSW,
sensitivity and subgroup analyses, the association remained
significant.

Elevated BUN levels were associated with
in-hospital mortality in patients with AMI and subsequent GIB.