Rochester, Minn. -- Rheumatoid arthritis patients are likelier than the average person to develop chronic kidney disease, and more severe inflammation in the first year of rheumatoid arthritis, corticosteroid use, high blood pressure and obesity are among the risk factors, new Mayo Clinic research shows. Physicians should test rheumatoid arthritis patients periodically for signs of kidney problems, and patients should work to keep blood pressure under control, avoid a high-salt diet, and eliminate or scale back medications damaging to the kidneys, says senior author Eric Matteson, M.D., Mayo rheumatology chair. The study is published in the American Journal of Kidney Diseases, the National Kidney Foundation journal .
Researchers studied 813 Mayo Clinic patients with rheumatoid arthritis and 813 without it. They found that over a 20-year period, people with rheumatoid arthritis have a 1 in 4 chance of developing chronic kidney disease, compared with the general population's 1-in-5 risk.
"That might not seem like a lot, but in fact that's quite a big difference, and it has important implications for the course of rheumatoid arthritis and for the management of the disease," Dr. Matteson says.
In addition, heart disease is more common in rheumatoid arthritis patients who have chronic kidney disease, he adds.
Factors contributing to a higher kidney disease risk for rheumatoid arthritis patients include use of corticosteroids such as prednisone and cortisone; a higher "sed rate" -- a blood test that measures inflammation -- in the first year of rheumatoid arthritis; obesity; hypertension; and dyslipidemia, abnormally high cholesterol in the blood, according to the study.
There are currently no medical guidelines specifically for the management of chronic kidney disease in rheumatoid arthritis, says Dr. Matteson, adding that he hopes the research will make physicians more alert to the risk of kidney disease in rheumatoid arthritis and lead to guidelines.
Dr. Matteson recommends that physicians be careful about the medications they give people with rheumatoid arthritis, to reduce the risk of medication-induced kidney disease. Rheumatoid arthritis patients should have blood tests and urine analysis once a year or more often to detect kidney problems, depending on the medications they are taking and on other conditions such as diabetes and high blood pressure they may have, he says.
"Kidney disease in patients with rheumatoid arthritis can be detected very simply, and the techniques are the same as are used in the general population," Dr. Matteson says.
To reduce their risk of developing kidney disease, patients should be attentive to their blood pressure and keep it under control, maintain a diet that isn't high in salt; avoid or reduce use of medications that are directly toxic to the kidneys; including nonsteroidal anti-inflammatory drugs; and get their rheumatoid arthritis and inflammation under as good of control as possible, he adds.
More research is planned to understand contributors to kidney disease in rheumatoid arthritis and how to intervene to reduce the risk, Dr. Matteson says.
The study was supported by National Institute of Arthritis and Musculoskeletal and Skin Diseases grant R01 AR46849 and by National Institute on Aging grant R01AG034676.
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