Heart disease and kidney disease interactions

6/12/2007

A study led by Peter McCullough, M.D. of Beaumont Hospital, Royal Oak, published in the June 11 issue of Archives of Internal Medicine, found three markers of chronic kidney disease related to the risk of heart disease. Furthermore, findings from another study, also part of the Kidney Early Evaluation Program, demonstrated heart disease is associated with subsequent kidney function decline and development of kidney disease.

"Many doctors are not aware that chronic kidney disease promotes and accelerates heart disease at a rapid rate," says Dr. McCullough, one of the authors of the national studies and chief, division of Preventive Medicine, Beaumont, Royal Oak. "And because kidney disease often is silent until dialysis is needed, those at risk need to have their blood sugar, blood pressure and cholesterol monitored on a monthly basis."

Chronic kidney disease is becoming increasingly prevalent in the United States and worldwide. It is associated with a wide variety of complications, including anemia (low red blood cell count, or red blood cells that are deficient in oxygen-transporting hemoglobin), nerve pain, bone disease, death and cardiovascular disease. Most patients with chronic kidney disease die of complications from heart disease rather than of kidney failure.

Dr. McCullough and his colleagues assessed a group of 37,153 individuals who were screened for kidney disease through a community-based program between 2000 and 2003. The participants (average age of 52.9 years) all reported a personal or family history of diabetes, hypertension or kidney disease on a screening survey. Patients had their blood pressure measured and provided blood and urine samples, which were processed to assess three markers of chronic kidney disease:

  • the rate at which kidneys filter blood, calculated based on levels of the waste product creatinine in the blood, also known as eGFR
  • anemia, determined by blood hemoglobin levels
  • slightly high levels of the protein albumin in the urine or microalbuminuria

Of the participants who were followed for a maximum of 47.5 months, 5,504 (14.8 percent) had eGFRs considered abnormal and signs of declining kidney function. In addition, 4,588 (13.1 percent) had anemia; and 15,959 (49.5 percent) had microalbuminuria. A total of 1,835 (4.9 percent) had a history of heart attack, 1,336 (3.6 percent) had a history of stroke and 2,897 (7.8 percent) had a self-reported history of heart attack or stroke.

Each of the three markers was associated with cardiovascular disease. More than one-fourth of the patients who had all three kidney disease measures had cardiovascular disease, and their survival rates over the course of the study were lower by approximately 93 percent than those of any other group.

The data suggest that screening for cardiovascular disease would be beneficial among patients with these risk markers but who do not report any history of cardiovascular disease symptoms.

"Because these patients are mainly under the care of primary care physicians and cardiologists, it is important to draw attention to the increased risk of kidney disease in this population, with goals of preventing further progression, managing kidney disease as they arise and adequately preparing individuals for kidney failure with timely nephrology referrals," say the authors. "Only with recognition of risk factors for kidney disease can this happen."