Serum potassium levels linked to long-term mortality post-MI

(HealthDay)—For patients with acute myocardial infarction (AMI), serum potassium levels are associated with long-term mortality risk, according to a study published in the April 15 issue of The American Journal of Cardiology.

Joon Seok Choi, M.D., from the Chonnam National University Medical School in Gwangju, South Korea, and colleagues examined the impact of serum potassium levels on long-term mortality in a cohort of 1,924 patients diagnosed with AMI. The average serum potassium levels were measured throughout hospitalization; patients were classified into five groups according to mean serum potassium: <3.5, 3.5 to <4.0, 4.0 to <4.5, 4.5 to <5.0, and ≥5 mEq/L.

The researchers found that patients with potassium levels of 3.5 to <4.0 mEq/L had lowest long-term mortality. Higher mortality was seen for patients with potassium levels <3.5 or ≥4.5 mEq/L. In a multivariate analysis, compared to patients with potassium levels of 3.5 to <4.0 mEg/L, mortality risk was significantly increased for serum potassium levels of 4.5 to <5.0 mEq/L and ≥5.0 mEq/L (hazard ratio, 1.71 [95 percent confidence interval, 1.04 to 2.81] and 4.78 [95 percent confidence interval, 2.14 to 10.69], respectively). An increased risk was also seen for patients with potassium levels of <3.5 mEq/L (hazard ratio, 1.55; 95 percent confidence interval, 0.94 to 2.56). No correlation was seen between serum potassium levels and the occurrence of ventricular arrhythmias.

"The results of the current analysis suggest that there is a need for change in our current concepts of the ideal serum potassium levels in patients with AMI," the authors write.

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