Risk calculation for hyperkalaemia in heart failure patients.

BACKGROUND We aimed to develop a model to estimate the risk of hyperkalaemia in patients treated for heart failure in a tertiary reference hospital and to identify precipitating factors. METHODS 125 congestive heart failure (CHF) patients were studied retrospectively. Thirty of these patients developed episodes of hyperkalaemia (K>or=5.5 mmol/l). Both groups were compared for possible risk factors for hyperkalaemia (age, glomerular filtration rate (GFR), New York Heart Association (NYHA) class, diabetes mellitus (DM), ejection fraction and medication use (ACE inhibitors, angiotensin receptor blockers, aldosterone antagonists). RESULTS On multivariate logistic regression analysis DM (OR 2.9, 95% CI=1.05 to 8.3, p=0.041), GFR<45 ml/min (OR 4.1, 95% CI=1.6 to 10.5. p=0.004) and NYHA class III-IV (OR 2.4, 95% CI=0.9 to 6.3, p=0.086) were independently associated with hyperkalaemia, whereas age, ejection fraction and medication sort and dose were not. Of the episodes of hyperkalaemia, 38% were precipitated by periods of dehydration (diarrhoea, fever) or change of medication. CONCLUSION We identified kidney function, diabetes mellitus and heart failure class as independent risk factors of hyperkalaemia. The majority of the hyperkalaemic episodes develop without a precipitating factor. This implies that heart failure patients in a tertiary reference hospital should be very closely monitored to minimize the risk for hyperkalaemia.