Ask the Doctors: Elevated creatinine levels can reflect 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 mg/dL, 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, a byproduct of creatine, an organic compound that supplies energy to the muscles.

Creatine plays an important role in physical activity and has become a popular dietary supplement.

Creatine and creatinine sound similar but 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’s filtered from the blood by the kidneys and exits the body via the urine. As a result, the concentration of creatinine that’s in the 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 called diabetic nephropathy. Sometimes referred to as diabetic kidney disease, it’s estimated to affect up to one-third of people in the United States with diabetes.

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

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 — milligrams per deciliter. For women, it’s 0.6 to 1.1 mg/dL.

His weakness and cramps are among symptoms that high creatinine levels and the impaired kidney function they suggest can cause. Others include high blood pressure, feeling nauseated, vomiting, chest pain and fluid retention.

There’s no single solution to lowering creatinine levels. Because meat is a source of creatine, from which creatinine is derived, eating less meat is important. Several studies have found eating more high-fiber foods can help with elevated creatinine. Dehydration can raise creatinine levels, so drinking enough water is important. Avoid tobacco, reduce salt, and limit the use of NSAIDs.

We’d urge your father to seek immediate medical care to evaluate his kidney function and be screened for kidney disease.

Dr. Eve Glazier and Dr. Elizabeth Ko are UCLA Health internists.