How To Minimize Diabetes- Related Kidney Damage

Maamoun Salam, MD

By Maamoun Salam, MD

If you have diabetes, you have no doubt been told that diabetes can damage your kidneys and may even cause kidney failure. Exactly how does higher-than-normal blood sugar cause kidney damage? Does this happen to everyone or just some people? Are you at risk? What are the effects? These are some of the many questions that may come to mind AFTER you leave the doctor’s office. We’ll try to address your concerns in this article.

First and foremost, let’s define what the kidneys do. Kidneys are the master regulators of fluid volume in the body, excreting more or less urine as needed to keep the rest of the body hydrated with fluid, but not overloaded. Kidneys also regulate all of the different salts in the body, excreting or holding onto sodium, potassium, chloride and others to keep the blood levels in a very narrow range. Kidneys excrete many byproducts of the body’s metabolism, and filter out toxins as needed. In addition, kidneys help to regulate blood pressure and produce a hormone called erythropoietin [ĕ-rith′rō-poy′ĕ-tin] that signals the bone arrow to make red blood cells. In addition, kidneys also regulate calcium, phosphorus and vitamin D, which are essential for bone integrity.

When kidneys fail, all of these functions are affected, and individuals can become very ill and even die if proper steps are not taken. Dialysis corrects some of the problems, such as fluid and salt regulation, and also eliminates toxins. However, erythropoietin is still lacking and may need to be taken separately as a medicine to treat low red blood cell counts seen in kidney failure. Blood pressure needs to be controlled, and additional measures may be needed to ensure bone health. Kidney transplantation corrects these additional problems, but requires medications to prevent rejection. Clearly, kidney failure is a devastating event in a person’s life.

Diabetes is a major risk factor for kidney disease, and the leading cause of new cases of kidney failure. Kidney failure from diabetes takes years to develop, and kidney problems can be identified far in advance in most cases. Thus, there are many steps that can be taken to keep you and your kidneys healthy. Here are some suggestions:


Kidney damage from diabetes is identified by one of two types of tests:

  • Albumin in your urine. This is also known as microalbuminuria or proteinuria. The test is done on a urine sample. It is important that you are not sick when your urine is tested, that you do not have a urinary tract infection and, for women, that you are not menstruating. All of these can falsely elevate the test result. You should have this test done every year and more often if there has been a significant change in either the prior test or your health. Albumin in the urine is a very early indicator of kidney damage and appears years before any of the kidney functions are affected. It serves as a warning sign that there could be problems in the future.
  • Creatinine is tested in blood samples and is commonly done as part of chemistry blood panels. Kidneys clear creatinine from blood and excrete it into the urine. Depending on your age, a plasma or serum creatinine of 0.7 – 1 milligrams per deciliter (mg/dL) would indicate normal kidney function, while a creatinine of >1.5 mg/dL clearly signals reduced kidney function. Your creatinine level, along with your age, sex and race can be entered into a formula to obtain an estimated glomerular filtration rate, or eGFR. That number tells your physician how well your kidneys are performing the filtering function. A normal eGFR is >90 ml/min/1.73m2, a slightly reduced eGFR is 60 – 90 ml/min/1.73m2, and definite kidney dysfunction is noted at an eGFR of

Chronic kidney disease, or CKD, is the term applied to persistent kidney problems, which is what we see in diabetes. CKD is divided into stages, which are listed in the table to the right. As kidney function declines, you may move from stage 1 or 2 to stage 3 or 4. You should be referred to a kidney specialist, a nephrologist, before you reach stage 4. CKD can progress into endstage renal disease (ESRD) that requires dialysis.

What can be done to prevent kidney disease in diabetes? There are very definite steps that you can take to prevent or slow the progress of kidney disease. Here are a few suggestions:

  • Keep your HbA1c (a measure of your average level of blood sugars in your body over the past three months) less than seven percent. Since high glucose – blood sugar – is the main driver for eye and kidney complications from diabetes, maintaining good-to-excellent control of your diabetes is the single best long-term strategy. If your HbA1c is as high as nine percent, your risk of kidney complications doubles compared to an HbA1c of seven percent.
  • Keep your blood pressure less than 140/98. Some guidelines suggest an even better number to shoot for is
  • Take a blood pressure medication that is either an ACE inhibitor, which is a pharmaceutical drug used primarily for the treatment of hypertension and congestive heart failure, or ARB, a medication that dilates the blood vessels, thereby reducing blood pressure. Your doctor will typically prescribe one of these drugs if your blood pressure is even a bit high or if you show signs of albumin in your urine. Long-term use of an ACE inhibitor or ARB reduces your risk of developing albumin in your urine and slows progression of loss of kidney function.
  • Stop smoking! If you smoke, please make efforts to stop. We don’t completely understand how smoking affects your kidneys, but smokers are at much higher risk of kidney complications than non-smokers.
  • Diet is important. Lose weight if you are carrying extra pounds. This reduces the burden on your kidneys and may prolong their life and your life if you have diabetes. Increase the amount of vegetables that you eat, and keep portions of proteins, especially red meats, and carbohydrates to a somewhat lower than usual level. Also, work hard to lower your salt intake.

Staying healthy with diabetes is a big job. It takes a lot of work and requires that daily attention be paid to many details, such as taking medications and eating the right foods. There are many, many things that can trip you up.....time pressures, financial pressures and social pressures. Doctors, nurses and educators know this, so don’t feel guilty. Just make an incremental effort to manage your health and fit diabetes into your life in such a way that you can keep up with all of the demands over the long term. We’re honored to be a part of your life and health.