Action to Control Cardiovascular Risk in Diabetes (ACCORD)

BACKGROUND:

Currently, about 17 million Americans have been diagnosed with diabetes and more than 90 percent of them have type 2 diabetes. The number of people with this form of diabetes, formerly known as adult onset or non-insulin dependent diabetes, is growing rapidly. By 2050, the number of Americans with diagnosed diabetes is projected to increase by 165 percent to 29 million, of whom 27 million will have the type 2 form. Cardiovascular disease (CVD) is the leading cause of death in people with type 2 diabetes; these individuals die of CVD at rates two to four times higher than those who do not have diabetes. They also experience more nonfatal heart attacks and strokes.

Type 2 diabetes is associated with older age and is more common in those who are overweight or obese and have a family history of diabetes. Women with a history of diabetes during pregnancy, adults with impaired glucose tolerance, people with a sedentary lifestyle, and members of a minority race/ethnicity are also at a greater risk for developing type 2 diabetes. African Americans, Hispanic/Latino Americans, American Indians, and some Asian Americans and Pacific Islanders are at particularly high risk for type 2 diabetes.

DESIGN NARRATIVE:

The three strategies tested in ACCORD included the following: (1) Blood sugar - ACCORD was designed to determine whether lowering blood glucose to a level closer to normal than called for in current guidelines reduces CVD risk. The study estimated effects on CVD of that level compared with a level that is usually targeted. (2) Blood pressure - many people with type 2 diabetes have high blood pressure. The blood pressure part of the trial was designed to determine the effects of lowering blood pressure in the context of good blood sugar control, that is to determine whether lowering blood pressure to normal (systolic pressure less than 120 mm Hg) will better reduce CVD risk, as compared to a usually-targeted level in current clinical practice (i.e., below the definition of hypertension; systolic pressure less than 140 mm Hg). (3) Blood Fats - Many people with diabetes have high levels of LDL ("bad") cholesterol and triglycerides, as well as low levels of HDL ("good") cholesterol. ACCORD participants who are selected for this part of the trial were assigned to an intervention to improve blood fat levels. This part of the study looked at the effects of lowering LDL cholesterol and blood triglycerides and increasing HDL cholesterol compared to an intervention that only lowers LDL cholesterol, all in the context of good blood sugar control. A drug from a class of drugs called "fibrates" was used to lower triglycerides and increase HDL cholesterol, whereas a drug from the class of drugs called "statins" was used to lower LDL cholesterol.