Schulman‐Marcus, Joshua

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.

Background Hyperkalemia has been associated with increased mortality in patients with myocardial infarction, but few data exist regarding hyperkalemia in cardiac intensive care unit ( CICU ) patients. We hypothesize that hyperkalemia is associated with increased mortality in unselected CICU patients. Methods and Results We retrospectively reviewed a historical cohort of 9681 CICU patients admitted from January 2007 to December 2015. Hyperkalemia was defined as admission potassium ≥5.0 mEq/L and hypokalemia as admission potassium <3.5 mEq/L. Multivariate logistic regression was used to determine predictors of in‐hospital mortality. Postdischarge survival was assessed using Kaplan–Meier analysis and Cox proportional hazards models. The mean age of included patients was 67±15 years, with 36% females, and in‐hospital mortality was 9%. Hyperkalemia occurred in 1187 (12.3%) and hypokalemia occurred in 719 (7.4%) patients. Both patients with hyperkalemia (unadjusted odds ratio, 2.85; 95% CI, 2.40–3.39; P <0.001) and patients with hypokalemia (unadjusted odds ratio, 2.31; 95% CI, 1.85–2.88; P <0.001) were at increased risk of unadjusted in‐hospital mortality. After adjustment for illness severity and renal function, only patients with hyperkalemia demonstrated increased risk of in‐hospital death (adjusted odds ratio, 1.44; 95% CI, 1.11–1.87; P =0.006). Among hospital survivors, only patients with hyperkalemia had lower postdischarge survival by Kaplan–Meier analysis ( P <0.001). After adjustment for illness severity and renal function, hospital survivors with admission hyperkalemia remained at increased risk for postdischarge mortality (adjusted hazard ratio, 1.20; 95% CI, 1.08–1.34; P <0.001). Conclusions Hyperkalemia on CICU admission is associated with higher in‐hospital and postdischarge mortality, independent of renal function and illness severity. These findings emphasize the importance of potassium abnormalities as a risk predictor in patients admitted to the CICU .