If you have diabetes, monitoring your blood glucose is important. But it’s not enough.
"It's crucial that everyone with diabetes -- and their doctors -- watch for signs of kidney problems too," says Rita Kalyani, MD, assistant professor of medicine at Johns Hopkins University. Kidney failure is a serious complication of diabetes, and diabetes is the leading cause of kidney failure.
"Unfortunately, many people who have diabetes don't realize that they have kidney disease," says Robert Stanton, MD, chief of nephrology at the Joslin Diabetes Center Clinic and associate professor of medicine at Harvard Medical School. "The obvious symptoms don't appear until the kidneys are failing."
There is good news: Simple tests can monitor kidney function and detect early diabetic kidney disease. Treating early disease can make a huge difference. Medications, dietary changes, and good control of glucose levels and blood pressure can slow down or prevent kidney damage.
The key is getting diagnosed early and starting treatment right away, Stanton says. If you have diabetes, here's what you need to know about preventing and treating kidney disease.
How Diabetes Damages the Kidneys
The kidneys filter the blood. They get rid of wastes in the body through urine, while the cleaned blood is sent back into the body.
In people with diabetes, the kidneys may be damaged so they don't filter blood as well. Small amounts of protein start to leak into the urine. Blood pressure goes up, further stressing the kidneys, and larger amounts of protein are found in the urine. As these changes occur, the kidneys lose even more ability to filter the blood and waste products start to build up in the blood.
High blood glucose levels -- the defining symptom of diabetes -- can damage cells in the kidneys over time. Diabetes may be associated with other causes of kidney damage too, says Janet B. McGill, MD, an endocrinologist and professor of medicine at the Washington University School of Medicine, St. Louis.
"Kidney damage in type 1 diabetes is largely the result of high glucose," McGill tells WebMD. "But in type 2, it could have many causes. There may be an interaction between high blood glucose, high blood pressure, inflammation, age, and genetics."
Untreated, the damage can get worse until the kidneys fail entirely. At this point -- called end stage renal disease -- the only treatment options are dialysis or a transplant.
What Are the Signs of Kidney Damage?
The obvious signs of kidney problems appear after there has been significant damage to the kidneys. They may include foamy urine, weight gain, water retention, loss of appetite, and feeling unwell. Anyone with those symptoms needs to see a doctor right away.
Early on, kidney damage tends to have no symptoms. The only way to know is with special blood and urine tests in the doctor's office. Normal glucose testing won't tell you about your kidney function. Traditional routine urine tests may not be sensitive enough, says Kalyani.