Post-cardiac surgery mortality in ICU patients with serum glucose–potassium ratio: A retrospective cohort analysis of the MIMIC-IV database

The serum glucose–potassium ratio (GPR) has emerged as a potential marker for various clinical outcomes. However, its association with post-cardiac surgery mortality in intensive care unit (ICU) patients remains unclear. To evaluate the association between GPR and in-hospital mortality in patients following cardiac surgery admitted to the ICU. This retrospective cohort study analyzed data from the Medical Information Mart for Intensive Care, version IV database (2008–2019). We included 590 patients aged 71.4 years on average, with a majority being male (66.4%) and non-White (69.8%). The primary exposure was GPR, defined as the ratio of serum glucose to potassium levels within 24 hours of ICU admission. Cox proportional hazards models were used to assess the relationship between GPR and in-hospital mortality, with adjustments for confounding variables. The univariate Cox regression analysis showed a significant association between GPR and in-hospital mortality (hazard ratio: 1.06; 95% confidence interval: 1.03–1.08, P  < .001). This relationship persisted in multivariate models (Model 3: hazard ratio: 1.07; 95% confidence interval: 1.04–1.11, P  < .001). Quartile analysis indicated that patients in the highest quartile of GPR (Q4 > 33) had a significantly higher risk of mortality compared to those in the lowest quartile (Q1 < 26). Subgroup analyses revealed significant interactions between GPR and age, with a trend towards higher mortality risk in older patients. In this cohort of post-cardiac surgery ICU patients, higher GPR was associated with increased in-hospital mortality. Further research is needed to explore the clinical implications of GPR as a potential prognostic marker in this patient population.