A patient I saw recently came in to discuss his lab results. Nick (not his real name) is 61 years old. He felt well and took no medications. His tests were within normal range except for his kidney test. The kidney function test (eGFR) was below 60, as was his prior test from July. By definition, a low eGFR (between 30 and 59) for more than three months meant he had stage 3 chronic kidney disease (CKD). Stage 3 CKD indicates that significant kidney function has been irrevocably lost. When a person reaches stage 5 CKD, dialysis or kidney transplantation will be required.

Chronic kidney disease is common. According to the Centers for Disease Control and Prevention, 1 in 7, or 15% of U.S. adults, are estimated to have CKD, and it affects 38% of people over the age of 65.

Nick is not alone in that 9 out of 10 people who have CKD are unaware they have it. Chronic kidney disease is asymptomatic until it is far advanced. Diagnosis requires specific blood and urine tests. Recognition of CKD is important, not only because of the risk of eventually needing dialysis, but also because CKD is an independent risk factor for cardiovascular disease. It is considered a coronary artery disease equivalent, meaning the risk is similar to having blockages in the arteries of the heart.

The sooner someone knows they have CKD, the earlier they can make changes to prevent progression. According to the National Institutes of Health, diabetes and high blood pressure are by far the most common risk factors for CKD. Almost 1 in 3 people with diabetes has CKD, and 1 in 5 people with high blood pressure has CKD. Underlying heart disease is another risk for CKD because there is an intimate link between the kidneys and the heart.

Family history of kidney disease is also a risk factor. Although individual genetic kidney disorders are uncommon, there are collectively more than 60 genetic disorders that can affect the kidneys. Other causes of kidney disease include infections, lupus, glomerulonephritis, lead poisoning, vasculitis and renal artery stenosis.

Normal aging is a common cause of kidney function decline. After the age of 40, eGFR declines about 1 point per year. Accelerated age-related loss of kidney function can be seen with hypertension, high cholesterol, smoking, complicated pregnancy, being born prematurely, obesity, male gender and certain racial groups. African Americans have more than 3 times and Latinos more than 1.3 times the risk of CKD compared to white Americans.

How can you slow the progression of CKD? If you have diabetes, aim to get it under control. If you have high blood pressure, aim for a blood pressure reading no higher than 130/80, preferably 120/80. Lose weight if overweight.

Exercise at least 150 minutes per week. In recent research published in JAMA Internal Medicine, 1,200 adults ages 70-89 participated in a study comparing those who engaged in moderate physical activity and exercise with those who received “health education.” In those who exercised, eGFR showed significantly less decline over the two-year trial.

Try to avoid medicines that could harm the kidneys, including NSAIDs (like ibuprofen), laxatives, certain antibiotics and certain supplements. The National Kidney Foundation lists a number of supplements that should be avoided. Also avoid “contrast” or special dye when getting x-rays unless essential for diagnosis.

According to the National Kidney Foundation, a plant-based diet can slow the progression of CKD.

Getting back to Nick, he was surprised to learn that he had chronic kidney disease. A recent CT scan of his kidneys showed tiny stones in his left kidney but was otherwise normal. His blood pressure was 131/73 and his weight 230 pounds. The underlying cause of his CKD was probably a combination of excess weight, mild hypertension and possible transient urinary tract obstruction from kidney stones. I explained that certain blood pressure medicines could protect his kidneys, but he was adamant about not taking medication. He was agreeable to eating a mostly plant-based diet, exercising more, losing weight and drinking plenty of fluids to prevent kidney stones.

Follow-up blood tests will be done in a few months to evaluate Nick’s kidney function, cholesterol and blood sugar. If his blood pressure becomes difficult to control, or if his eGFR falls into stage 4 CKD, he will be referred to a kidney specialist. Kidney disease is not just a low number in a lab report. It requires serious attention.