PHILADELPHIA (EGMN) C The use of potentially nephrotoxic dietary supplements is common in the U.S. general population and in patients with chronic kidney disease, according to a study reported Nov. 10 at the annual meeting of the American Society of Nephrology. Dr. Vanessa Grubbs of the University of California reported that 1 in 10 adults in the United States, regardless of kidney disease, use dietary supplements that are potentially harmful to the kidneys, but ironically, when these populations are warned, they instead believe that these supplements are beneficial to their health. The National Kidney Foundation (NKF) has identified 39 herbs as potentially harmful, especially in the context of chronic kidney disease, but it is very difficult to have physicians supervise their use by patients “because dietary supplements containing the aforementioned herbs are subject to food-like rather than drug-like regulation.” Among the dietary supplements identified by the NKF as potentially harmful to the kidney, the more common are those used as diuretics (including buchu leaf and juniper berries) and those that can interact with prescribed medications, such as onychomycetes, echinacea, ginkgo, garlic, ginger, and blue asclepias. To determine the rate of use of dietary supplements containing the above herbs in the general U.S. population and in the chronic kidney disease population, Dr. Grubbs and colleagues used data from the National Health and Nutrition Examination Survey from 1999 to 2008 on the use of dietary supplements in the last 30 d among 21,169 nonpregnant adults aged 20 years and older in the United States. For analysis, chronic kidney disease was defined as a urinary albumin/creatinine ratio ³ 30 mg/g and an estimated glomerular filtration rate (eGFR) ³ 60 ml/(min・1.73 m2) (stage I/II) or an eGFR of 15 to 59 ml/(min・1.73 m2) (stage III/IV). To assess the use and risk of potentially harmful supplements among patients with chronic kidney disease, the investigators used multivariate logistic regression analysis with US population weights. Results showed that more than half of the respondents reported using dietary supplements, with 15.3% reporting using supplements containing at least 1 potentially harmful herb. Although crude estimates of dietary supplement use increased with increasing severity of chronic kidney disease (51.4% for those with no kidney disease, 49.1% for those with stage I/II kidney disease, and 65.8% for those with stage III/IV kidney disease were reported), the use of potentially harmful supplements decreased with increasing severity of chronic kidney disease, with 16.1%, 13.0%, and 13.0% reported in the above populations, respectively. However, as the severity of chronic kidney disease increases, the use of potentially harmful supplements decreases, with 16.1%, 13.0%, and 10.0% reported in these populations, respectively. However, after correcting for demographics, co-morbidities, and medical visits, it was found that “chronic kidney disease status was not a meaningful determinant of the use of any supplement or potentially harmful supplements. The researchers concluded that a significant proportion of patients with chronic kidney disease are using potentially harmful dietary supplements, and until the government updates its regulatory standards for dietary supplements, the task of reducing the harm caused by inappropriate dietary supplement use will have to fall on the shoulders of physicians and patients.