A dangerous complication of diabetes is kidney damage. Because your kidneys filter waste from your blood, and because diabetes that is not well-controlled results in too much glucose (sugar) in the blood, the kidneys can be forced to work overtime. Eventually, strained kidneys will not work well anymore, and will perhaps even fail — a diabetes complication to be avoided at all costs.
Diabetes: How Kidneys Are Affected
Kidneys contain millions of tiny blood vessels called capillaries that act as blood filters. When your blood flows through these vessels, waste particles are squeezed through the capillary walls and are eventually excreted in your urine.
If it is not well controlled, type 1 diabetes can cause high blood glucose levels, which can force your kidneys to work harder to do this filtering. The capillaries become more porous and start to leak. Proteins that should normally not be filtered out start to appear in your urine.
"People with type 1 diabetes sometimes develop little holes in the filtering devices in their kidneys so they start to spill small amounts of protein, called proteinuria," says Jay Cohen, MD, medical director of the Endocrine Clinic in Memphis and clinical assistant professor of family medicine at the University of Tennessee.
"If there is uncontrolled diabetes on top of the proteinuria," says Dr. Cohen, "that can lead to a difficulty of the kidneys being able to get rid of a poison in your blood called creatinine." Cohen says that creatinine can build up in your blood, which puts you at risk of kidney failure.
But Cohen stresses that just because you have type 1 diabetes doesn't mean that your kidneys will become damaged or will fail. "Many people with type 1 diabetes never develop kidney problems," he says. The better your glucose levels are managed over a long period of time, the less likely you are to develop kidney complications of diabetes.
Diabetes: The Damage From High Blood Pressure
Hypertension, or high blood pressure, is a serious illness that makes the heart pump harder and can damage blood vessels everywhere in your body, including those leading to the kidneys. If kidney function is affected, the kidneys won’t remove waste and extra fluid properly. That extra fluid then goes back into the blood vessels, and will raise your blood pressure even more.
Overall, high blood pressure is the reason why 25,000 people experience kidney failure every year in the United States.
If you have both high blood pressure and diabetes, you are at particular risk of kidney disease. Managing your blood pressure, which includes quitting smoking, decreasing salt intake, and exercising regularly, is very important when trying to prevent kidney disease.
Diabetes: Kidney Disease Prevention
You should visit your endocrinologist about three times a year, says Cohen. Your endocrinologist should check your urine for a protein called microalbumin, which can signal that your kidneys are leaking protein, as well as the amount of creatinine in your blood. High levels of creatinine indicate that your kidneys are having problems filtering wastes.
You also should follow all of your medical team's recommendations for keeping your blood glucose levels under control. This may include a special meal plan, regular exercise, insulin and other medications, and regular monitoring of your blood glucose.
Call your doctor promptly at the first sign of a bladder or kidney infection, such as pain or burning during urination, a frequent urge to urinate, cloudy or reddish urine, fever, shakiness, or pain in your back or side. If you have diabetes, having a bladder or kidney infection can be serious and result in further kidney damage.
Diabetes: Kidney Disease Treatment
If you do have signs of kidney damage, medication can relax or decrease the pressure on the kidneys and prevent the progression of kidney disease, says Cohen. Two types of medications that can slow kidney damage are angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), both of which are used to treat high blood pressure.
There are also medications you should avoid: Taking painkillers like aspirin or acetaminophen too often can damage your kidneys. Talk to your doctor about the safest over-the-counter pain relief choices for you. If one of your other doctors recommends a daily dose of aspirin to protect your heart, be sure that your endocrinologist and others on your medical team are aware of it and can monitor you accordingly.