Getting That Blood Sugar Just Right

Diabetes patients with chronic kidney disease may need more precise blood sugar control

(RxWiki News) In order to avoid complications of diabetes, patients have to keep a careful watch on their blood sugar levels. If a diabetes patient also has kidney disease, blood sugar levels may need to be even more precise.

Patients with diabetes and chronic kidney disease may be more likely to die if their HbA1c (a measure of blood sugar over three months) is too high or too low.

"Control your blood sugar if you have diabetes and kidney disease."

Lowering HbA1c levels can prevent or slow the progression of kidney disease in people with diabetes. That being said, can HbA1c levels get so low that it is harmful?

Marcello Tonelli, M.D., S.M., of the University of Alberta, and colleagues set out to answer that question.

Among patients with diabetes and chronic kidney disease, HbA1c levels lower than 6.5 percent and higher than 9 percent were associated with a higher risk of death.

The researchers also found that higher HbA1c levels may increase the risk of poor outcomes for diabetes patients with kidney disease, regardless of their initial glomerular filtration rate, or eGFR (a way to measure kidney function and determine the stage of kidney disease).

Among patients with an eGFR of 30.0 to 59.9 mL/min, the risk of end-stage renal disease (kidney failure) was increased by 22 percent for those with HbA1c levels of seven to nine percent and by 152 percent for those with HbA1c levels more than nine percent, compared to those with HbA1c levels lower than seven percent.

The results also show that the increased risk of kidney failure from high HbA1c levels is greatest among those who had better kidney function at the beginning of the study.

According to the authors, "These findings suggest that appropriate and timely control of HbA1c level in people with [diabetes] and [chronic kidney disease] may be more important than previously realized." However, they add, blood sugar control that is too extreme may be linked with a greater risk of death.

In order to come to these conclusions, Dr. Tonelli and colleagues identified and studied 23,296 people with diabetes and chronic kidney disease (defined as having a eGFR lower than 60.0 mL/min). Over the 46-month follow-up period, 3,665 people died and 401 developed end-stage renal disease.

The study is published in the Archives of Internal Medicine

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Review Date: 
November 29, 2011