If you have diabetes, you probably worry about the effects of the disease on organs like your eyes or heart. But it affects other part of your body as well, including your kidneys.
"Diabetes is the top cause of chronic kidney disease in the United States," stresses Andrew Malone, MD, a kidney specialist at the Washington University School of Medicine in Saint Louis. About one in three adults with diabetes has chronic kidney disease, according to the US Centers for Disease Control and Prevention (CDC), and every 24 hours, 170 people with diabetes begin treatment for kidney failure.
But while these stats sound scary, they don't have to be your destiny. "If you live a healthy lifestyle and keep your diabetes well controlled, that ups the odds that your kidneys will stay in decent shape," says Dr. Malone. Here's what to know.
Diabetic kidney disease is exactly how it sounds: a type of kidney disease caused by diabetes. It's also known as diabetic nephropathy.
"When you have diabetes, over time the small blood vessels in your body are injured," explains Dr. Malone. When that happens in your kidneys, they can't do their job and clean your blood properly. As a result, your body holds onto more water and salt than it should, and waste materials build up in your blood. How quickly or slowly this happens depends on how well-or poorly-your diabetes is controlled.
"If you catch it early and treat the underlying diabetes, your chronic kidney disease will get better," says Priyamvada Singh, MBBS, a kidney specialist at the Ohio State University Wexner Medical Center in Columbus, Ohio. "But if you let your diabetes go uncontrolled and your blood glucose run wild, the damage may happen very quickly."
Unfortunately, like chronic kidney disease in general, it can be symptomless in the early stages, says Dr. Malone. That's why it's so important for your doctor to do a urine test where they check for albumin, a type of protein found in the blood, every year. Symptoms to look out for, regardless, include:
Protein in your urine
An urge to pee often, especially at night.
Elevated blood pressure.
Frequent urinary tract infections. Diabetes itself causes damage to nerves in your body. "This can make it hard for you to fully empty your bladder, and if your urine remains there for a long time, you can develop an infection," says Dr. Singh. This is especially true if your diabetes isn't well controlled, because if your urine has a high sugar level, it encourages the growth of bacteria.
If you don't get screened for kidney disease every year, the condition can progress until you end up in the late stages, which can lead to kidney failure. This can cause:
Nausea and vomiting
Loss of appetite
Muscle cramps, especially in your legs
Anemia, or a low red blood cell count
The need for less insulin, since your damaged kidneys don't break it down as well
There is good news: if you keep your diabetes well controlled, you reduce your chances of developing chronic kidney disease (and if you do get it, there's much less chance of it progressing to later stages), stresses Dr. Malone. This usually involves a four-pronged approach:
Control your blood glucose levels
This starts with checking your A1C, a blood test that shows you your average blood glucose level over the past three months, says the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Unlike blood glucose checks you may do at home, this is done at a lab or at your doctor's office. The goal for most people with diabetes is an A1C below 7%. Your diabetes care team can help you reach that through a combination of diet, exercise, and medications. They'll also let you know how often you should get your A1C checked.
Control your blood pressure
If you have diabetes, you are also at higher risk to develop hypertension, which is the second leading cause of kidney failure, according to NIDDK. The blood pressure goal for most people with diabetes is below 140/90, or 130/80 for certain people at high risk, says the American Heart Association.
The good news is that some of the same medications doctors use to lower blood pressure also help slow kidney damage. "Two types, ACE inhibitors and ARBs, have actually been shown to slow kidney damage in people with diabetes who have high blood pressure," explains Dr. Singh. These include lisinopril, enalapril, losartan and candesartan (hint: The names of these medicines all end in –pril or –sartan).
Eat a healthy diet
A healthy diabetes diet is a healthy diet for anyone: think foods like fruits, veggies, healthy fats, and lean protein. But it's slightly different if chronic kidney disease (CKD) is in the mix, says Melissa Ann Prest, DCN, RDN, a renal nutritionist in Chicago and a spokesperson for the Academy of Nutrition and Dietetics.
"Many of my patients don't grasp how important it is that they follow a low-sodium diet," she explains. "But their kidneys are less able to filter salt out from their blood, which can lead to high blood pressure, which in turn can worsen chronic kidney disease."
You can't go wrong with focusing on fresh, unprocessed foods, she encourages, and if you do buy a packaged or canned product make sure it contains less than 5% of the daily value for sodium. "I also explain to patients that they need to avoid salt substitutions, which they might have turned to if they just had diabetes: they're high in potassium, which most people with CKD need to limit," she adds.
You may also need to watch the potassium, phosphorus, and protein in your diet. That may mean limiting seemingly healthy fare like lean cuts of meat, dairy, beans, nuts, whole-grain bread, and certain fruits such as oranges and tomatoes. It's a good idea to work with a registered dietician who's trained in both diabetes and chronic kidney disease (it's covered by Medicare, and most private insurance). An RN can help design a meal plan to help your body function at its best, says the CDC.
Take the right medications
A certain class of diabetes medications known as SGLT2 inhibitors do double duty to both lower blood glucose levels and slow down progression of CKD in people with diabetes, says Dr. Singh. These include:
Sometimes, kidney disease is diagnosed too late, or it progresses because your diabetes is too poorly controlled. This is known as kidney failure, and it means that your kidneys function at less than 15% of their normal capacity, per Mayo Clinic. About 30% of people with type 1 diabetes, and up to 40% of those with type 2 diabetes eventually go on to develop kidney failure, according to the National Kidney Foundation.
Unfortunately, at this point there are only two options: dialysis or a kidney transplant. The good news is most people with diabetes do well with peritoneal dialysis (PD), a form of home dialysis, says Dr. Singh. This means that you can do it at night, while you're asleep, so you can work and do other activities during the day.
It's also safe for people with diabetes to get a kidney transplant, adds Dr. Malone. "Oftentimes, when people get a new one, they find that they need a higher dose of insulin because their new kidney is able to break it down again," he says. You'll also usually find that your appetite improves, too, but just make sure to stick to healthy fare to help you manage your diabetes. "Otherwise, you'll end up going through the same cycle of chronic kidney disease again," cautions Dr. Malone.