Abstract 16642: Hyperkalemia is Associated With Increased Short and Long-Term Mortality Among Unselected Cardiac Intensive Care Unit Patients

Abstract

Introduction: Studies have demonstrated an association between hyperkalemia and increased mortality in patients with myocardial infarction, but limited data exist regarding hyperkalemia and associated death among unselected cardiac intensive care unit (CICU) patients. Hypothesis: Hyperkalemia is associated with mortality in CICU patients. Methods: Historical cohort of 9,681 CICU patients admitted from January 2007 to December 2015 with serum potassium measured on admission. Hyperkalemia was defined as admission potassium >=5.0 mEq/L, normokalemia as admission potassium 3.5-4.9 mEq/L, and hypokalemia as admission potassium <3.5 mEq/L. Multivariate logistic regression was used to determine predictors of hospital mortality. Post-discharge survival was assessed using Kaplan-Meier analysis and Cox proportional hazards models. Results: Mean age was 67±15 years with 3,629 (36%) females and hospital mortality of 9%. Hyperkalemia occurred in 1,187 (12.3%), and hypokalemia occurred in 719 (7.4%). Compared to normokalemic patients, both hyperkalemic patients (unadjusted OR 2.85, 95% CI 2.40-3.39; P<.001) and hypokalemic patients (unadjusted OR 2.31, 95% CI 1.85-2.88; P<.001) were at increased risk of hospital mortality. After adjustment for illness severity and renal function, only hyperkalemic patients were at increased risk of hospital death (adjusted OR 1.35, 95% CI 1.07-1.69; p = 0.01), while hypokalemic patients were not (P = NS). Among hospital survivors, hyperkalemic patients had lower post-discharge survival by Kaplan-Meier analysis (P <0.001), while hypokalemic patients had similar survival compared to normokalemic patients (p = NS). After adjustment for illness severity and renal function, hospital survivors with hyperkalemia were at increased risk for post-discharge mortality compared with normokalemic patients (adjusted HR 1.16, 95% CI 1.05-1.28; p=.003). Conclusions: Hyperkalemia on CICU admission is associated with higher hospital and post-discharge mortality, independent of renal function and illness severity. This emphasizes the importance of potassium abnormalities as a risk predictor in patients admitted to the CICU.