Basnet S, et al. – This study assessed the association of changes in serum potassium levels with mortality risk among hospitalized patients with congestive heart failure (CHF) in the US, using the National Inpatient Sample database. Findings demonstrated that hypokalemia increases mortality and hyperkalemia is associated with mortality benefit in this patient population, irrespective of the etiology or subtype of heart failure. Hypokalemia increased the risk of cardiac arrhythmias. Overall, a beneficial effect of normokalemia and hyperkalemia was observed in patients admitted with CHF and, this can be achieved by use of potassium supplements, ACE inhibitors and K–sparing diuretics.

Methods

• Researchers utilized the National Inpatient Sample database and selected patients (≥18 years and non-pregnant) admitted with CHF in US hospitals from 2009 to 2011.
• They substituted code for CHF (428) based on International Classification of disease-9 (ICD-9) with Clinical Classification Software-Diagnoses of 108.
• They added ICD-9 codes 404.03, 404.11, 404.13, 404.91, 404.93 and 402.11 to include all etiologies of heart failure.
• The ICD-9 codes for hypokalemia is 276.8 and hyperkalemia is 267.7.
• For analysis, they used STATA version 13.0 (College Station, TX).
• They performed multivariate analysis of mortality among CHF patients while controlling for age, sex, race, smoking, obesity, dyslipidemia, diabetes, hypertension and Charlson comorbidity index.

Results

• The total study population was based on 2,660,609 discharge records.
• Researchers found that hypokalemia was associated with increased mortality risk (OR: 2.025) and hyperkalemia was associated with decreased mortality risk (OR: 0.935) in comparison to normokalemia.
• They noted similar association with etiologies (Acute coronary syndrome, Ischemic heart disease, valvular heart disease, hypertensive heart disease, cardiomyopathy, atrial fibrillation) and subtypes (systolic, diastolic and combined) of CHF with serum potassium levels.