Mixed results for intensive blood-sugar control

Intensive control of blood-sugar levels among patients with type 2 diabetes mellitus may reduce the risk of microalbuminuria and macroalbuminuria, signs of kidney damage, but evidence is lacking regarding the effect over renal end points, according to the results of a study published May 28 in Archives of Internal Medicine.

According to researchers, a number of trials have demonstrated that intensive glycemic control reduces albuminuria; therefore, current treatment guidelines recommend the control for the prevention of renal disease. Steven G. Coca, DO, MS, Yale University School of Medicine, New Haven, Conn., and colleagues conducted the systematic review and meta-analysis to explore whether intensive glycemic control prevents renal end points beyond albuminuria.

Those end points include doubling of the serum creatinine level, end-stage renal disease, and death from renal disease.

The researchers searched 3 databases for randomized trials from January 1, 1950, to December 31, 2010, that compared levels of microalbuminuria and macroalbuminuria with clinical renal end points in patients with type 2 diabetes receiving intensive glucose control versus those receiving conventional glucose control.

The authors identified 7 trials including 28,065 adults who were monitored for 2 to 15 years. They noted a statistically significant reduction in microalbuminuria and macroalbuminuria in patients who received intensive therapy. However, 163,828 patient-years of follow-up data were inconclusive on clinically important renal end points.

Results led the researchers to conclude, “there is little compelling reason to initiate intensive glycemic control in midstage of the disease with the aim of preventing renal failure.”

One physician raised concerns over the short follow-up time of the studies upon which the analysis was based in a comment accompanying the study.

David M. Nathan, MD, Diabetes Unit, Massachusetts General Hospital, Harvard Medical School, Boston, noted that there is a long time frame in the development of complications, that diabetes is the major cause of blindness, renal failure, and amputations in adults, and that early intensive therapy and control of other recognized risk factors is necessary to improving the long-term prospects of patients with diabetes. 

Therefore, he argued that “the introduction of intensive therapy, with the goal of achieving near-normal HbA_1c levels and usual achievement of a level of approximately 7%, has altered the clinical course of retinopathy, nephropathy, and neuropathy.”

He cautioned physicians not to be too quick to abandon the goal HbA_1c level of less than 7% for most patients.