Linear association between serum potassium levels and 28-day mortality among ICU patients with diabetes and sepsis: a multicenter study

Abstract

Background: Dysregulation of serum potassium is a common electrolyte disturbance in critically ill patients, and both hypokalemia and hyperkalemia have been linked to adverse outcomes in sepsis. However, the relationship between serum potassium levels and mortality in ICU patients with diabetes and sepsis remains poorly understood. Methods: A retrospective cohort study was conducted using data from the eICU Collaborative Research Database (2014–2015). The study included 5,104 adult ICU patients with diabetes and sepsis from 208 hospitals in the U.S. Serum potassium levels measured within 24 h of ICU admission were categorized into hypokalemia (<3.5 mmol/L), normokalemia (3.5–5.0 mmol/L), and hyperkalemia (>5.0 mmol/L). Multivariable logistic regression models were used to assess the association between serum potassium levels and 28-day ICU mortality. Results: Of the 5,104 patients (mean age, 66.8 years; 49.1% male), 1,046 (20.5%) had hypokalemia, 3,377 (66.2%) had normokalemia, and 681 (13.3%) had hyperkalemia. After adjusting for demographic factors, comorbidities, and treatment measures, each 1 mmol/L increase in serum potassium was associated with a 25% higher risk of 28-day mortality (adjusted OR, 1.25; 95% CI, 1.07–1.47). Compared to hypokalemia, hyperkalemia was associated with significantly higher mortality risk (adjusted OR, 1.86; 95% CI, 1.17–2.96). A linear relationship was observed between serum potassium levels and mortality (P = 0.006), differing from the previously reported U-shaped relationship in general ICU populations. Conclusions and relevance: Elevated serum potassium levels were independently associated with increased 28-day mortality in ICU patients with diabetes and sepsis. These findings suggest that potassium management strategies should be specifically tailored for this high-risk patient population.