I have diabetes, and my doctor says that as a diabetic, I need to get my blood pressure down lower. I know high blood pressure isn't good for you, but I don't really see what high blood pressure has to do with my diabetes.

Thank you for your question about diabetes and high blood pressure. Don't feel badly about not knowing that there is a link between the two problems, since many people are also unaware!

Over the past few years several research studies have shown clear evidence that patients with diabetes should be considered "special people" in terms of blood pressure control. The reason for this is that the negative impact of high blood pressure on kidney function and heart function is much greater for a diabetic patient than for a hypertensive patient without diabetes. While the American Diabetes Association recommends keeping your blood pressure under 130/80, the American Heart Association says you should aim for lower than 120/80. Lower is better!

This goal for BP was determined by research studies to be protective for keeping normal diabetic kidney function. As you may know, diabetes can damage the kidneys and is a cause of kidney failure in some diabetic patients. Some of these patients may need dialysis or even transplantation. Therefore, if we can protect the kidneys from the bad effects of diabetes, we might spare patients these undesirable outcomes and allow them to lead a normal life.

Kidney function in diabetics can best be assessed by blood tests (BUN-blood urea nitrogen and Creatinine) checked at least annually. Another very important test is "urinary microalbumin" which measures how much protein is getting past the kidneys into the urine. (In a sense, this checks the "leakiness" of the kidneys filter system) The urinary microalbumin test becomes abnormally high when diabetes has begun to damange the kidneys and is a good early marker for future kidney problems. It is recommended that it be measured at least once per year.

If the value is elevated, doctors often start patients on medications called "ACE-inhibitors" that can make the urinary microalbumin normal and protect kidney function. Examples of ACE-inhibitor medications are Vasotec, Prinivil, Zestril, and several others brand names. These ACE-inhibitor medications also are commonly used to control high blood pressure in patients with hypertension. They can be an excellent choice for diabetics who also have hypertension since there can be a "double benefit" in using ACE-inhibitor medicine.

Some research suggests that diabetic patients may benefit from ACE-inhibitor medication even before there is actual high blood pressure or evidence of kidney problems on the urine test. Of course, there are other good medications used to treat high blood pressure that your doctor may select based on your personal history and physical examination findings.

The bottom line is to keep the blood pressure under control. I find it very helpful for patients to purchase a home blood pressure kit. After teaching them how to use it (it is easy!), they can monitor their BP at home each day and make sure things are in good control. We review their BP readings together at their periodic office visits, and I find this gives a more complete picture than a single office reading.

I hope this information clarifies your question. Feel free to write back if you have any additional comments. Good luck in your blood pressure control efforts!

-- Dr. Bruce Biller is an internist with subspecialty training in endocrinology and a special interest in diabetes. He is director of the Harvard Business School Health Services and physician to the Harvard University Health Services.

First published August 2, 2005
Last updated February 11, 2008
Copyright © 2005 Consumer Health Interactive