The influence of International Normalized Ratio on the prognosis of acute coronary syndrome patients in intensive care units: A retrospective analysis based on MIMIC-IV database

Objective: To investigate the infulence of the International Normalized Ratio (INR) on the prognosis of patients with acute coronary syndrome (ACS) admitted to intensive care units (ICUs). Methods: A retrospective analysis was conducted on ACS patients from the MIMIC-IV 2.0 database, who were admitted to ICUs for the first time between 2008 and 2019 and met the study criteria. The association between the initial INR upon admission and the prognosis of ACS patients was assessed using a restricted cubic spline model at a continuous level. Based on the restricted cubic spline (RCS) curve, patients were stratified into three groups, and a multivariate Cox regression model was applied to analyze the effect of INR on the prognosis of ACS patients. Results: When INR was ⩽1.0, the mortality risk gradually decreased with increasing INR levels; when INR ranged between 1.0 and 1.5, the mortality risk rose significantly with further elevation of INR; when INR exceeded 1.5, the mortality risk stabilized at a persistently high level, with minimal fluctuations observed despite substantial changes in INR values. Multivariate Cox regression analysis also demonstrated that patients in the medium (1.0-1.5) and high (>1.5) INR groups exhibited significantly higher mortality risks compared to those in the low (⩽1.0) INR group. Conclusions: Fluctuations in the INR among patients with ACS admitted to the ICU are associated with an increased risk of mortality and adversely affect patient prognosis.