Asessment of blood urea nitrogen to creatinine ratio as a predictor of mortality in ST-elevation myocardial infarction patients undergoing thrombolytic therapy: a cross-sectional study

Abstract

Objectives: Given the increasing number of ST-elevation myocardial infarction (STEMI) and the related healthcare expenses and medical outcomes, as well as the frequent occurrence of kidney problems in this patient population, the current research aims to explore the effect of blood urea nitrogen to creatinine (BUN/Cr) ratio on the in-hospital mortality (IHM) of STEMI patients undergoing thrombolytic therapy. Methods: This study is a cross-sectional analytical study conducted in 2021 at Shahid Madani Hospital, affiliated with Tabriz University of Medical Science, which investigated the relationship between the BUN/Cr ratio and IHM in patients with STEMI who received thrombolytic treatment between 2017 and 2019. Patients with other causes of ST elevation, those undergoing dialysis, or those with incomplete medical records were excluded. Data were collected from patient medical records. The primary outcome was in-hospital mortality, with secondary outcomes including the occurrence of heart failure and the need for blood transfusion—chi-square tests for categorical and t-tests for continuous variables. A p-value of less than 0.05 was considered statistically significant. Results: A total of 398 patients were diagnosed with STEMI and treated with thrombolytic 330 (82.9%) patients were men. High BUN and Cr had a significant correlation with high mortality rates (P <0.01). However, BUN/Cr didn’t have a substantial relationship with IHM and one-year mortality (P-value = 0.46). The most common in-hospital complication was heart failure (HF), and a higher need for blood transfusion was significantly related to high rates of BUN/Cr (P <0.01). Conclusions: While high BUN and Cr levels were significantly associated with increased mortality rates, the BUN/Cr ratio was not significantly related to IHM. These results suggest that although elevated BUN and creatinine indicate poor prognosis, the BUN/Cr ratio may not be a standalone predictor of in-hospital mortality. Further research is needed to validate these findings and identify other factors affecting patient outcomes.