Trial of a Drug to Decrease the Risk for Heart Disease in Patients with Mild Kidney Failure

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The summary below is from the full report titled "Renal Insufficiency as a Predictor of Cardiovascular Outcomes and the Impact of Ramipril: The HOPE Randomized Trial." It is in the 17 April 2001 issue of Annals of Internal Medicine (volume 134, pages 629-636). The authors are JFE Mann, HC Gerstein, J Pogue, J Bosch, and S Yusuf, for the HOPE Investigators.

What is the problem and what is known about it so far?

Severe kidney disease is known to increase the risk for heart (cardiac) disease, but it is not known whether mildly abnormal kidney function increases heart disease risk. The Heart Outcomes and Prevention Evaluation (HOPE) study evaluated people at high risk for heart disease from many causes and the effects of ramipril (a special class of drug that lowers blood pressure) on that risk. This study included many people with mild kidney disease.

Why did the researchers do this particular study?

The researchers reanalyzed the data from the HOPE study to find out whether mild kidney disease itself increased the risk for cardiac disease and whether ramipril could be protective in this particular group of patients.

Who was studied?

9297 patients in the HOPE study who were at high risk for cardiac disease for a variety of reasons.

How was the study done?

Tests of kidney function were performed at the beginning of the study. The participants were then randomly assigned to treatment with either ramipril or an inactive placebo pill and were followed for 3.5 to 5.5 years. Because high blood pressure and diabetes can cause heart disease by themselves, patients with those disorders were analyzed separately. The primary outcomes studied were cardiac death, heart attack, or stroke. Outcomes of secondary interest were the total number of deaths, hospitalizations for heart failure, and performance of surgical procedures to increase blood flow to the heart.

What did the researchers find?

980 participants fulfilled the criteria for mild kidney disease. These people were older; were more likely to be men; had higher blood pressure, more coronary artery disease, and lower levels of "good cholesterol" (high-density lipoprotein cholesterol); and used more medicines to prevent heart attacks and high blood pressure than those with normal kidney function. Even taking those factors into account, mildly abnormal kidney function itself was an important predictor of heart disease. The more abnormal the kidney function, the higher the risks for heart disease and death from any cause. Ramipril substantially reduced the risk for bad outcomes in the patients with reduced kidney function. Ramipril produced no more adverse side effects than did placebo.

What were the limitations of the study?

Reanalysis of data collected for another purpose is not the best way to answer a particular medical question. Also, the data may not apply to the general population since the people studied had preexisting blood vessel disease or had diabetes with at least one other risk factor for heart disease.

What are the implications of the study?

Mild kidney disease should be considered a risk factor for heart disease; drugs such as ramipril may help reduce this risk.