Renal disease and the heart

Associate Editor-In-Chief:

Overview
An estimated 10 to 20 million people have chronic kidney disease (CKD). While many will never develop kidney failure, others will, joining more than 400,000 people annually treated with dialysis or a kidney transplant. Cardiovascular disorders accounts for half of all deaths among people with kidney failure.


 * Cardiovascular disease accounts for more than half of all deaths among people with renal failure.
 * Even early or mild kidney disease places a person at higher risk of acute coronary syndromes and heart failure, as well as cardiovascular disease related death.
 * Hypertension (high blood pressure) and diabetes are major risk factors for chronic kidney disease and heart disease. The development of chronic kidney disease in persons with diabetes or hypertension further increases the risk of developing cardiovascular disease.
 * Hypertension increases the risk of cardiovascular disease, and severe hypertension can cause extensive and rapidly progressive kidney damage. Newer medications that better control blood pressure, however, can slow the rate of kidney damage only by about 50 percent.
 * In comparison, death from cardiovascular disease is 10 to 30 times more likely in dialysis patients.
 * Kidney disease by itself increases the risk of cardiovascular disease, even with concurrent diabetes, hypertension and high cholesterol.
 * Numerous studies reported that kidney disease accelerates heart disease, even before the kidneys are damaged to the point of needing dialysis or transplantation.

Clinical Trials
A pair of epidemiology studies confirmed that chronic kidney disease independently increases the risk of developing cardiovascular disease, even among people with early kidney disease and after considering other risk factors such as diabetes, hypertension and high cholesterol.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) funded study followed more than 1.1 million adults from the Kaiser Permanente Renal Registry in San Francisco for nearly 3 years; average age was 52 years. The investigators found that when kidney function (GFR) dropped, the risk of death, cardiovascular events such as heart disease and stroke, and hospitalization increased. Compared to patients whose GFR was at least 60 (ml per min. per 1.73 m2):


 * The increased risk of death ranged from 17 percent in those whose GFR was between 45 and 59 to about 600 percent in those whose GFR was less than 15
 * The increased risk of CVD events ranged from 43 percent in those whose GFR was between 45 and 59 to 343 percent in those whose GFR was less than 15,
 * The increased risk of hospitalization ranged from 14 percent in those whose GFR was between 45 and 59 to 315 percent in those whose GFR was less than 15.

The industry-funded VALIANT study related CKD to deaths from CVD in a 2-year drug-treatment trial of more than 14,500 heart-attack patients. The researchers found death rates ranging from 14.1 percent in patients whose GFR was at least 75 to 45.5 percent in those whose GFR was less than 45.

The investigators attribute the increased risk of death from CVD in part to complications of kidney disease, including anemia, oxidative stress, changes in calcium and phosphate regulation, inflammation, and conditions promoting clotting. The researchers also suggest that other kidney-related factors such as protein in the urine and elevated blood levels of both homocysteine and uric acid may increase the risk of CVD and death. Furthermore, they found that common CVD therapies such as aspirin and beta-blockers were “curiously underused” in CKD patients with lower kidney function, perhaps inspired by a fatalist mind-set that may be a self-fulfilling prophecy.

Renal Cell Carcinoma and Heart
Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology

Source

 * National Institute of Health