Mild hyperkalemia and outcomes in chronic heart failure: a propensity matched study.

Pubmed ID: 19500863

Pubmed Central ID: PMC2888731

Journal: International journal of cardiology

Publication Date: Oct. 29, 2010

Affiliation: University of Alabama at Birmingham, Birmingham, Alabama 35294-2041, USA.

MeSH Terms: Humans, Male, Female, Aged, Case-Control Studies, Cohort Studies, Algorithms, Middle Aged, Chronic Disease, Heart Failure, Prognosis, Statistics, Nonparametric, Follow-Up Studies, Alabama, Hyperkalemia, Potassium, Predictive Value of Tests, Biomarkers

Grants: R01 HL085561, P50-HL077100, R01 HL085561-03, K23 DK064649, R01 HL085561-02, R01 HL085561-04, 5-R01-HL085561-02, K23 DK064649-05, P50 HL077100

Authors: Ahmed MI, Ekundayo OJ, Love TE, Aban I, Aronow WS, Ahmed A, Perry GJ, Mujib M, Bakris G, Campbell RC, Pitt B, Sanders PW

Cite As: Ahmed MI, Ekundayo OJ, Mujib M, Campbell RC, Sanders PW, Pitt B, Perry GJ, Bakris G, Aban I, Love TE, Aronow WS, Ahmed A. Mild hyperkalemia and outcomes in chronic heart failure: a propensity matched study. Int J Cardiol 2010 Oct 29;144(3):383-8. Epub 2009 Jun 5.



BACKGROUND: Compared with serum potassium levels 4-5.5 mEq/L, those <4 mEq/L have been shown to increase mortality in chronic heart failure (HF). Expert opinions suggest that serum potassium levels >5.5 mEq/L may be harmful in HF. However, little is known about the safety of serum potassium 5-5.5 mEq/L. METHODS: Of the 7788 chronic HF patients in the Digitalis Investigation Group trial, 5656 had serum potassium 4-5.5 mEq/L. Of these, 567 had mild hyperkalemia (5-5.5 mEq/L) and 5089 had normokalemia (4-4.9 mEq/L). Propensity scores for mild hyperkalemia were used to assemble a balanced cohort of 548 patients with mild hyperkalemia and 1629 patients with normokalemia. Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for association between mild hyperkalemia and mortality during a median follow-up of 38 months. RESULTS: All-cause mortality occurred in 36% and 38% of matched patients with normokalemia and mild hyperkalemia respectively (HR, 1.07; 95% CI, 0.90-1.26; P=0.458). Unadjusted, multivariable-adjusted, and propensity-adjusted HRs for mortality associated with mild hyperkalemia were 1.33 (95% CI, 1.15-1.52; P<0.0001), 1.16 (95% CI, 1.01-1.34; P=0.040) and 1.13 (95% CI, 0.98-1.31; P=0.091) respectively. Mild hyperkalemia had no association with cardiovascular or HF mortality or all-cause or cardiovascular hospitalization. CONCLUSION: Serum potassium 4-4.9 mEq/L is optimal and 5-5.5 mEq/L appears relatively safe in HF. Despite lack of an intrinsic association , the bivariate association of mild-hyperkalemia with mortality suggests that it may be useful as a biomarker of poor prognosis in HF.