Misguided Kidney Tests for Heart Risk

Researchers doubt usefulness of measuring blood levels of phosphorus, parathyroid hormone, and calcium

(RxWiki News) To evaluate the risk of heart disease in patients with chronic kidney disease, doctors run tests that measure certain biomarkers, specifically blood levels of phosphorus, parathyroid hormone, and calcium. Kidney disease patients are regularly tested to gauge their risk of heart disease, but new research casts doubt on the usefulness of these tests.

Dr. Giovanni F.M. Strippoli, renal research coordinator at the Mario Negri Sud Consortium in Italy and senior author of the study, and colleagues reviewed nearly 50 studies from the past 60 years in order to see if the these biomarkers were actually good indicators of heart disease risk in patients with chronic kidney disease.

dailyRx Insight: Kidney patients, Ask your doctor if your next blood test is necessary.

After reviewing numerous past studies, researchers saw little evidence of a connection between higher levels parathyroid hormone and calcium and having heart disease. However, they did find that higher levels of phosphorus were associated with an increased risk of death in people with kidney disease. The authors write that only one study provided good information on the association between heart-related death and the biomarkers.

Chronic kidney disease affects over 26 million people in the United States, with many millions more being affected by instances of acute kidney disease. Chronic kidney disease results when the kidneys gradually lose their ability to filter out waste products from the blood and maintain the proper balance of water, salts and proteins in the blood. Chronic kidney failure can be caused by a multitude of reasons, but is commonly seen in patients with high blood pressure and diabetes, as well as patients with autoimmune diseases. Acute kidney failure is similar to chronic kidney failure in that the kidneys fail to do their job, but acute kidney failure happens at a more rapid pace, usually due to loss of blood flow, toxic drugs, or obstruction of urine flow. Symptoms of kidney failure are variable, but people will often feel tired, have muscle cramps, trouble sleeping, swollen feet and puffy eyes, and an increased need to urinate. Treatment includes medications such as ACE inhibitors and ARBs, although they are not curative. Eventually many patients need replacement of the hormones erythropoietin and calcitriol, and eventually dialysis and kidney transplantation. Diagnosis is made by measuring substances in the blood and urine.

The study is published in the Journal of the American Medical Association.

Review Date: 
March 16, 2011