Association between blood urea nitrogen-to-potassium ratio and 30-day all-cause mortality in patients with non-traumatic subarachnoid hemorrhage

Background: The mortality risk is exceptionally high in non-traumatic subarachnoid hemorrhage (SAH). Elevated blood urea nitrogen (BUN) levels and hypokalemia are prevalent issues in patients with non-traumatic SAH. To explore the correlation between the blood urea nitrogen-to-potassium ratio (BPR) and 30-day all-cause mortality in non-traumatic SAH patients. Methods: We systematically extracted specific clinical data from the Medical Information Mart for Intensive IV (MIMIC-IV) database. To assess the prognostic relevance of the BPR, we categorized patients into those experiencing in-hospital mortality within 30 days and those surviving, subjecting them to both univariate and multivariate Cox regression analyses. The optimal BPR cut-off value was identified using Receiver Operating Characteristic (ROC) curve analysis, employing the maximum Youden index to predict survival status. Furthermore, we employed Kaplan-Meier (K-M) analysis to illustrate survival curves. Results: A cohort comprising 608 patients with non-traumatic SAH was enrolled in the investigation. Multivariate Cox regression analysis identified the BPR as an independent predictor of all-cause mortality within 30 days of admission for patients with non-traumatic SAH (Hazard Ratio [HR], 1.13; 95 % Confidence Interval [CI], 1.04---1.23; P<0.05). Further refinement resulted in the establishment of an optimized prediction model (AUC=83.61 %, 95 % CI: 79.73 %- 87.49%) for forecasting all-cause mortality at 30 days post-hospital admission in patients with non-traumatic SAH. Conclusion: The BPR emerges as an independent prognostic indicator for all-cause mortality within the initial 30 days of admission among non-traumatic SAH patients.