Kidney health, chronic kidney disease: What PCPs need to know
CDC data estimate that more than 20 million people in the United States have chronic kidney disease with varying levels of seriousness. In addition, the American Kidney Fund — a nonprofit organization that works on behalf of those with kidney disease — suggests that nine out of 10 people who have moderately decreased kidney function may not even know it.
According to the CDC, diabetes and elevated BP both increase a patient’s risk for developing chronic kidney disease. Other risk factors include lupus, high cholesterol, obesity and CVD, or a family history of kidney disease.
Healio Family Medicine spoke with LaTonya Hickson, MD, nephrologist at the Mayo Clinic in Rochester, Minnesota, as well as Anna Burgner MD, associate program director, Nephrology Fellowship Training Program, Vanderbilt University School of Medicine, Nashville, Tennessee, about what primary care physicians (PCPs) can do to promote kidney health and kidney disease.
Question: What prescription and over-the-counter drugs should PCPs be advising their patients to avoid?
Hickson: In general, patients with chronic kidney disease or diabetic kidney disease should be cautious taking over-the-counter medications or dietary/herbal supplements that have not been approved by their personal doctor(s) or health care providers. In particular, medications used for pain such as non-steroidal anti-inflammatory drugs, may worsen kidney function and should be avoided. Recently, proton pump inhibitors, commonly used drugs for the treatment of gastric refluxthat are available over-the-counter or through prescription, have been associated with an increased risk for kidney injury. Interval assessment of kidney function over time may be important and if the function changes, these drugs should be recognized as a potential culprit.
Burgner: Many medications have the potential to be toxic to the kidneys. Therefore, it is best for patients to only take medications they absolutely need. If a patient needs to take a potentially toxic kidney medication long term, it is a good idea to monitor kidney function for any signs of toxicity. If a patient has kidney disease or is at risk for kidney disease it is important to weigh potential risks and benefits with all potentially kidney-toxic medications with the patient. In addition, patients should be encouraged to discuss all over the counter drugs and supplements they take with their physician so that an assessment can be made to look for kidney toxicity or interactions with other medications. I recommend all my patients avoid herbal supplements. Herbal supplements are not regulated by the FDA so there is no guarantee on the supplements content, dose, or purity. Some herbal supplements have been found to have kidney-toxic substances, including heavy metals and aristolochic acid.
Q: Are there certain foods a PCP can recommend to a patient to consume or avoid to keep their kidneys healthy?
Hickson : Overall, avoidance of high sodium and high saturated fats foods is recommended. Adequate fluid intake is important, particularly in warm climates or seasons. Some research suggests a Mediterranean diet higher in fruits and vegetables, lower in red meats, but higher in fish/poultry, and more plant-based protein emphasis is favorable. However, the diet recommendations may substantially change as kidney disease progresses. In this case, certain ‘healthy’ foods higher in potassium and phosphorus should then be minimized.
Burgner: Staying healthy helps keep the kidneys healthy. So eating a healthy, well balanced diet is never a bad idea! If a patient has chronic kidney disease a low sodium diet can help with improving blood pressure control and help with avoiding volume overload.
Q: What other steps can PCPs advise their patients to do, to maintain kidney health?
Hickson : Maintaining a healthy lifestyle is key. Regular physical activity decreases the risk for unhealthy weight gain and high blood sugars. Avoiding tobacco use and excessive alcohol intake is also important.
Burgner: Staying up to date on immunizations and age appropriate cancer screenings is important. A bad case of influenza could take someone with healthy kidneys and put them on dialysis. If a patient has hypertension or diabetes mellitus it is very important to treat them aggressively and get them under control before they develop kidney disease.
Q: Are there misconceptions involving kidney disea se among PCPs ?
Hickson: More than 670,000 patients were treated for end-stage kidney failure in the U.S. in 2014 and presently more than 100,000 people are on the kidney transplant waiting list. Thousands of people die each year waiting for a kidney transplant. The gift of organ donation, such as a kidney, either while we are living or at death can often improve and lengthen the lives of those in dire need of a transplant.
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Q: What else should primary care physicians should about managing patients with kidney disease?
Hickson: A drug commonly used to treat diabetes, metformin, previously had a black box warning to avoid use in patients with moderately advanced kidney failure due to a risk for a rare condition in which acid builds up in the bloodstream. Last summer, the FDA changed the labeling for metformin (and combination drugs using metformin) allowing continued use of the drug when kidney function falls between an estimated glomerular filtration rate between 30 and 45 mL/min/1.73m2. This is important because the many benefits of metformin may now be available to patients with chronic kidney disease who otherwise would have had to stop the drug or never initiate it. However, patients with kidney disease should still be carefully monitored for side effects and a drug dose reduction as kidney function falls is generally needed.
Burgner: There is a lot of very exciting research going on involving kidney disease. There are several exciting phase 3 clinical trials looking at new methods to slow the progression of chronic kidney disease in diabetic nephropathy. There is ongoing research looking into new methods of renal replacement therapy including a wearable dialysis vest. A colleague of mine here at Vanderbilt University Medical Center, Bill Fissell, MD, is doing research on designing an implantable artificial kidney! I think we are entering an exciting age in nephrology where we are going to see numerous advances to help our patients live healthier and happier lives.