Blood Pressure and Your Kidneys

Here at Diabetes Flashpoints, we often address the sometimes confusing science of blood pressure and diabetes — most recently in September, when we discussed the mixed conclusions of a study on blood pressure and risk of cardiovascular disease in people with Type 2 diabetes. That study found that while having lower blood pressure reduced participants’ risk of developing cardiovascular disease, it didn’t always lower their overall risk of death.

Now, a new study is out that examines the effects of blood pressure on the risk of kidney disease in people with Type 1 diabetes. It’s worth noting, though, that these findings may be relevant to anyone who has had diabetes — Type 1 or 2 — for an extended period of time, since both types of diabetes can raise your risk of kidney disease.

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Published in this month’s issue of the journal Diabetes Care, the study followed 1,441 participants over an average follow-up period of 24 years — enough time to see risk factors for kidney disease, and many cases of the disease itself, develop. Participants were between 13 and 39 years old at the beginning of the study, and were randomly assigned to practice either conventional or intensive blood glucose control as part of the original study.

As noted in a Physician’s Briefing article on the study, during the follow-up period, 84 participants developed at least Stage 3 chronic kidney disease (CKD). In addition, 169 participants developed macroalbuminuria (having high protein levels in the urine — a risk factor for kidney disease). Both of these outcomes, it turns out, were related to blood pressure. Participants with systolic (the top number) blood pressure below 120 mm Hg were 68% less likely to develop kidney disease — and 41% less likely to develop macroalbuminuria — than participants with systolic blood pressure between 130 and 140. The American Diabetes Association currently recommends setting a blood pressure goal of below 140 for most people with diabetes.

What’s more, the study found no correlation between either conventional or intensive blood glucose control and kidney disease risk. This means that blood pressure may be a better predictor of kidney disease risk than blood glucose control in many people with diabetes.

What’s your take on this study — does it confirm your understanding of how important blood pressure control is, or are you surprised that its effect on kidney disease risk was so large? Do you think doctors — including your own — spend enough time discussing blood pressure numbers and treatments with people with diabetes? If you have kidney disease, do you suspect that your blood pressure may have played a role in its development? Leave a comment below!