A study released Sunday said, diabetics who seek to aggressively lower their blood pressure and cholesterol are not reducing their risk of a heart attack and could suffer negative side effects.
The results of the landmark Action to Control Cardiovascular Risk in Diabetes (ACCORD) clinical trial appear to repudiate years of medical advice for type-2 diabetics who face a high risk of heart attacks, stroke or death from cardiovascular disease.
"This information provides guidance to avoid unnecessarily increasing treatment that provides limited benefit and potentially increases the risk of adverse effects," said Susan Shurin, acting director of the National Heart, Lung and Blood Institute at the National Institutes of Health, ACCORD's primary sponsor.
The study, presented here at the 59th annual conference of the American College of Cardiology, followed 10,251 type-2 diabetics between the ages of 40 and 79 for an average of 10 years.
All participants joined the study with an especially high risk of cardiovascular disease.
The study sought to evaluate the effects on heart disease in diabetics of aggressively lowering blood sugar or blood pressure and lowering bad cholesterol while increasing good cholesterol.
All participants were enrolled in the blood sugar control trial, with some also assigned to the blood pressure trial and others assigned to the cholesterol treatment.
Researchers from 77 centers in the United States and Canada divided 4,733 of the participants with elevated blood pressure into two groups to receive either intensive treatment with blood pressure medication or standard treatment.
After an average follow-up of about five years, researchers found no significant differences between the two groups.
There were 208 "cardiovascular events" in the intensive group and 237 events in the standard group, the study said, though it did find that the risk of stroke was about 40 percent less in the intensive group.
However, "participants in the intensive blood pressure group were more likely to have complications such as abnormally low blood pressure or high levels of blood potassium," the researchers cautioned.
The cholesterol trial sought to discover whether a treatment that simultaneously lowered bad cholesterol while raising good cholesterol would more effectively decrease heart disease risk than a treatment that only targeted bad cholesterol levels.
Researchers assigned 5,518 participants to the trial, but found that the combined treatment failed to lower the risk of heart attack, stroke, or death from cardiovascular disease more effectively.
"Overall, the results of the ACCORD lipid trial do not support the use of combination therapy with a fibrate and a statin to reduce cardiovascular disease in most high-risk adults with type 2 diabetes," said lead author Henry Ginsberg, a professor of medicine at Columbia University College of Physicians and Surgeons.
"These new ACCORD results indicate that we do not generally need to treat even more intensively than standard practice," said Denise Simons-Morton, a co-author of the study.
But she cautioned that the results were not a repudiation of the need to take standard measures to keep blood pressure and bad cholesterol levels low.
"The treatment strategies used in the ACCORD standard control groups have previously been shown to be effective," she said.
"So the findings in no way detract from the important point that controlling blood pressure and LDL cholesterol levels reduce cardiovascular risk -- not only in patients with diabetes, but in all patients with elevated levels."