Patients with type 2 diabetes are at an increased risk for developing cardiovascular disease. Diabetes can affect blood flow to the heart, resulting in angina and heart attack. It could also cause heart failure. Besides, diabetes could also affect the blood supply to the brain, leading to transient ischemic attacks and stroke.
Controlling blood sugar in diabetes helps to reduce the risk of individuals suffering from these complications. However, it is unclear whether an intensive control of blood glucose will be more effective than standard therapy in reducing the incidence of cardiovascular events.
AdvertisementA recently completed study (the ACCORD or Action to Control Cardiovascular Risk in Diabetes trial) investigated whether intensive control of blood glucose would reduce the risk for developing serious cardiovascular events. The study was conducted in middle-aged and elderly diabetics between 40 and 79 years of age from the United States and Canada. These patients were suffering from diabetes over a prolonged period. They had a cardiovascular risk factor or previous cardiovascular disease and had glycated hemoglobin levels equal or greater than 7.5%. Glycated hemoglobin levels indicate the level of diabetes control. A person with a glycated hemoglobin level of more than 6% is said to be suffering from diabetes.
The patients enrolled in the study were randomized into two groups. One group was the intensive therapy group. This group was treated to reduce glycated hemoglobin level below 6%. The other group was the standard treatment group where the target glycated hemoglobin level was between 7 and 7.9%.
The study found that intensive blood glucose lowering did not result in a significant decrease in cardiovascular events. In fact, at the end of 3.5 years, the intensive therapy had to be terminated due to increased mortality in this group. The study was further continued for up to 5 years wherein the intensive therapy was stopped and the standard therapy was adopted for all patients.
Though the deaths are not attributed to the lower blood sugar levels and not all were related to the cardiovascular system, the exact reason for these deaths was unclear. In fact, the patients in the intensive treatment group had a reduced incidence of non-fatal heart attacks. However, due to the increased number of deaths in this subgroup, the authors do not recommend intensive diabetes therapy for high - risk patients with advanced type 2 diabetes.
Source: Long-Term Effects of Intensive Glucose Lowering on Cardiovascular Outcomes.
The ACCORD Study Group. N Engl J Med 2011; 364:818-828