Ask the Doctors: Elevated creatinine levels can impact kidney function

DEAR DOCTORS: My father has diabetes and high blood pressure. Sometimes, he fails to follow medical care for these diseases. Now his level of creatinine has reached 2.6 milligrams per deciliter, which is very high. He is getting weak and has cramps at night. How do you decrease high creatinine?

DEAR READER: Creatinine is a natural waste product produced by the activity of our muscles. It's a byproduct of creatine, an organic compound that supplies energy to the muscles. We recently wrote about creatine, which plays an important role in physical activity and has become a popular dietary supplement. We bring this up because creatine and creatinine sound similar. However, they are two distinct compounds and have very different effects on the body. It's important not to confuse the two.

Each of us produces and excretes creatinine in a continual cycle. It is filtered from the blood by the kidneys and exits the body via urine. As a result, the concentration of creatinine that is present in someone's blood or urine is used as a measure of how well the kidneys are functioning. Among the conditions that can contribute to developing high creatinine levels is a common complication of Type 1 and Type 2 diabetes known as diabetic nephropathy. Sometimes referred to as diabetic kidney disease, it is estimated to affect up to one-third of people in the United States living with diabetes.

Over time, high blood sugar levels can damage the blood vessels that serve the kidneys and also the nephrons, which are tiny structures that serve as filters. Individuals with diabetes who fail to manage blood sugar levels are at particular risk of this type of damage. It leaves the kidneys unable to effectively clear the blood of waste products and other toxins, which can cause a cascade of increasingly grave health problems.

The results of your father's creatinine blood test are indeed quite high. The normal range for an adult man is 0.7 to 1.3 mg/dL (that's milligrams per deciliter). For women, it is 0.6 to 1.1 mg/dL. The symptoms that you say he is experiencing -- feeling weak and experiencing cramps -- are among those that high creatinine levels, and the impaired kidney function they suggest, can cause. Additional symptoms include high blood pressure, feeling nauseated, vomiting, chest pain and fluid retention.

When it comes to lowering creatinine levels, there is no single solution. Because meat is a source of creatine, from which creatinine is derived, lowering the amount of meat in the diet is important. Several studies have found that adding high-fiber foods to the diet can have a beneficial effect on elevated creatinine. Dehydration can raise creatinine levels, so drinking enough water is also important. Avoid tobacco products, reduce salt and limit the use of nonsteroidal anti-inflammatory drugs, each of which can put a strain on the kidneys.

In your father's case, with uncontrolled diabetes and high creatinine levels, we urge him to seek immediate medical care. The doctor will evaluate your father's kidney function and screen him for kidney disease. Based on a physical exam, test results and a medical history, your father will be advised of the appropriate path forward.

Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.

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