In an analysis from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, one of the largest studies of its kind to determine whether intensive blood glucose (sugar) control worked better than standard blood sugar control among diabetics, results show that the benefits of intensive therapy need to be balanced against the increase in total and cardiovascular disease-related death, increased weight gain, and high risk for severe low blood sugar.
The study is published by the Lancet to coincide with the American Diabetes Association's 70th Scientific Sessions in Orlando. The analysis is written by Dr. Faramarz Ismail-Beigi, a diabetes specialist with University Hospitals Case Medical Center, Case Western Reserve University, and colleagues for the ACCORD trial group.
ACCORD was a randomised trial done with more than 10,000 patients in 77 clinical sites, including University Hospitals Case Medical Center, in North America. People with Type 2 diabetes for an average of 10 years, high blood sugar concentrations and cardiovascular disease were randomly assigned to an intensive lowering of blood sugars or standard therapy.
The study examined patients who underwent intensive glucose-lowering treatment for 3.5 years (increased medication aimed at lowering A1C levels to less than 6 percent) and were then given standard treatments (aimed at achieving A1C levels of 7.0-7.9 percent) for the remaining 1.5 years, compared with standard treatment for the duration of the study. The intensively treated patients did not see a reduced incidence of cardiovascular disease.
In addition, the groups did not differ in overall measures of microvascular health, for example, in the progression rates to kidney failure, major vision loss, or advanced peripheral neuropathy, a common nerve problem in diabetes that usually begins as tingling or numbness in the feet.
However, there were some microvascular improvements noted, such as a reduced incidence of albuminuria (protein in the urine, a marker of kidney disease) in the intensive group, compared to those receiving standard treatment, along with fewer cataract extractions during the study period. Visual acuity (sharpness of vision) and nerve function scores also were better for the intensive group than for the standard-treatment group, suggesting that intensive lowering of blood glucose may also help prevent eye and nerve damage.
"Patients who develop macroalbuminuria are prone to renal failure and cardiovascular events," said Dr. Ismail-Beigi, the lead researcher on this portion of the ACCORD trial. "Less protein in the urine is a very good sign."
Though the visual acuity tests were somewhat subjective, Dr. Ismail-Beigi said, they could indicate that intensive glucose lowering helps to prevent eye damage.
Dr. Ismail-Beigi said that the study indicates the importance of individualized, patient-centered therapy for patients. A decision on the aggressiveness of therapy depends on what stage of the disease patients are in. For those patients who are newly diagnosed with diabetes, intensive, aggressive therapy could delay the onset of some of the complications of diabetes, such as kidney disease and eye problems. For patients who have had diabetes 10 years or longer and have complicating heart factors, intense therapy would not be prudent because of the associated higher risk of cardiovascular death.
The National Heart Lung and Blood Institute, which sponsored this landmark study, prematurely halted the intensive blood-glucose lowering strategy after 3.5 years, in February 2008, due to safety concerns caused by an unexpected higher incidence of death in the intensive glucose lowering treatment group compared with the standard treatment group. Patients in the intensive treatment arm of the study were transitioned into the standard treatment arm for the remainder of the trial's five years, which has now concluded.
Other portions of the ACCORD trial confirmed that neither more intensive lowering of blood pressure nor treatment of blood lipids with a fibrate and a statin drug reduce cardiovascular risk in people with established type 2 diabetes who are at severely high risk for cardiovascular events.
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