Tight Blood-Sugar Control Shows Mixed Results for Health of Kidneys: Study

TUESDAY, May 29 (HealthDay News) -- Intensive control of blood sugar levels reduces the risk of certain signs of kidney damage among diabetics, new research indicates.

However, the evidence did not show that intensive control lowers the risk of actually developing severe kidney disease.

The two signs of kidney damage that the study focused on are conditions known as microalbuminuria and macroalbuminuria. These are characterized by excessive levels of protein in the urine, usually resulting from damage to the filtering units of the kidneys, according to background information in the study published May 28 in the Archives of Internal Medicine.

But, the review of data from seven clinical trials that included more than 28,000 adult patients did not find conclusive evidence that intensive blood-sugar control was related to a reduced risk of serious kidney problems, including kidney failure or death from kidney failure.

"Our analysis demonstrates that, after 163,828 patient-years of follow-up in the seven studies examined, intensive glycemic [blood sugar] control lessens albuminuria," but there's not enough data to say if that benefit extends to kidney disease or kidney failure, wrote Dr. Steven Coca, of Yale University, and colleagues.

This may mean that there's little point to beginning intensive blood-sugar control in the mid-stage of type 2 diabetes in an attempt to prevent kidney failure, they concluded.

However, an expert not involved in the study says the studies included in this meta-analysis were too short to assess how intensive blood-sugar control might affect the risk of kidney failure in patients with type 2 diabetes.

"Although implementing intensive therapy is difficult and imposes burden and expense, all of the primary data continue to support its long-term benefit," Dr. David Nathan, of Massachusetts General Hospital, wrote in an accompanying editorial.

Another expert agreed.

"I feel this [finding] is misleading since most of the studies included in the analysis had relatively short durations of 'intensive' treatment and also fairly short durations of follow-up," said Dr. Tracy Breen, director of diabetes care at North Shore-LIJ Health System in New Hyde Park, N.Y.

She added that "microvascular complications often take many years to develop - any analysis that includes trials with less than 10 years of follow-up may not have the statistical power to show difference in clinical events."