Poor kidney function ups death risk in heart failure

Impaired kidney function raises the risk of death and hospital admission in patients with chronic heart failure, even among those patients with fairly well preserved heart-pumping action, study findings suggest.

So-called "renal insufficiency" has been shown to increase the risk of death in chronic heart failure patients, but most studies have involved patients with markedly reduced left ventricular ejection fraction (LVEF) - a measure of the heart's blood-pumping strength.

Less is known about the impact of kidney function on heart failure in the presence of preserved heart-pumping power.

To investigate, Dr. Hans L. Hillege, from the University of Groningen in the Netherlands and associates studied 2,680 heart patients - 1087 of whom had an LVEF greater than 40 percent indicating preserved heart-pumping action.

At baseline, 36 percent of patients had poorly functioning kidneys. During a median follow-up of 34.4 months, 950 patients died of cardiovascular causes or were admitted to the hospital for heart failure, and there were 625 deaths from all causes.

The authors report that both poorly functioning kidneys and lower LVEF were significant independent predictors of worse outcomes.

"The strong independent effect of renal function in our analysis after adjustment for numerous cardiac risk factors shows that renal function is a valuable predictive variable in evaluating outcomes," the authors maintain, "even if it probably represents partly underlying atherosclerotic or hypertensive vascular disease."

SOURCE: Circulation, February 6, 2006.