Deaths Stop Part Of Diabetes Trial

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Main Category: Diabetes
Also Included In: Cardiovascular / Cardiology
Article Date: 07 Feb 2008 - 3:00 PDT

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Part of a large North American clinical trial comparing aggressive with less aggressive blood sugar treatment of diabetes and cardiovascular disease in adults with type 2 diabetes has stopped 18 months early because the more aggressive treatment increased risk of death. The less aggressive treatment arm of the study has not been stopped and is likely to complete its full term.

The main sponsor of the trial, the National Heart, Lung, and Blood Institute (NHLBI), which is part of the National Institutes of Health in the US, stopped the trial treatment arm that intensively lowered blood sugar below current recommended levels after an interim analysis of the data showed that it increased the risk of death compared with a less intensive treatment strategy, said the NHLBI in a prepared statement. The participants in the intensive treatment arm will now be treated with the less intensive strategy.

The study is called ACCORD, which stands for Action to Control Cardiovascular Risk in Diabetes and is being carried out in over 70 centres in Canada and the US. The study enrolled 10,251 participants, and over an average treatment period of four years, there were 3 deaths per 1,000 more in the intensive treatment group compared to the standard treatment group (257 deaths out of 5,128 participants, compared with 203 out of 5,123 respectively). However, the death rates in both groups were reported to be lower than that seen in similar groups in other studies said the NHLBI.

The trial was seeking to establish whether intensively lowering blood sugar would significantly reduce the risk of heart attacks, stroke, or death from cardiovascular disease in people with type 2 diabetes who were especially at high risk of such cardiovascular events. The participants had had diabetes type 2 for over 10 years, and were aged between 40 and 82 at enrollment.

It was prompted partially by previous research that suggested reducing blood sugar levels to that found in non-diabetic adults was linked with lower rates of cardiovascular events among patients with type 2 diabetes. What was missing was a proper large scale, randomized clinical trial to confirm those findings before more aggressive blood sugar control could be rolled out in treatment programmes.

However this is not what they found, as Director of the NHLBI, Dr Elizabeth G Nabel explained to the press:

"A thorough review of the data shows that the medical treatment strategy of intensively reducing blood sugar below current clinical guidelines causes harm in these especially high-risk patients with type 2 diabetes."

"Though we have stopped this part of the trial, we will continue to care for these participants, who now will receive the less-intensive standard treatment. In addition, we will continue to monitor the health of all participants, seek the underlying causes for this finding, and carry on with other important research within ACCORD," she added.

The recommendation to stop the aggressive treatment arm was made by the trial's Data and Safety Monitoring Board (DSMB), an independent group of 10 experts in a number of disciplines including diabetes, cardiovascular disease, medical ethics, trial design, epidemiology, patient care and biostatistics. Part of the remit of the DSMB is to monitor participant safety.

The target blood sugar level of the aggressive treatment arm was below 6 per cent of hemoglobin A1C, which is on a par with adults who do not have diabetes. The standard treatment group is aiming for a level that is normally attained by American adult diabetics under standard treatment in the US (A1C between 7 and 7.9 per cent).

Hemoglobin is a group of molecules inside red blood cells that carry blood sugar by combining with glucose to form glycosylated (or glycated) hemoglobin. There are different types, of which A1C has been found to be a reliable marker for monitoring blood sugar in people with diabetes.

The ACCORD participants that were in the intensive treatment group will now be treated with the same treatment goal as the less intensive group, that is to attain an A1C hemoglobin level between 7 and 7.9 per cent. All participants will continue with their treatment until the end of the trial in June 2009, said the NHLBI.

Director of the Division of Diabetes, Endocrinology, and Metabolic Diseases at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, another trial sponsor), Dr Judith Fradkin said:

"The ACCORD findings are important, but will not change therapy for most patients with type 2 diabetes. Few patients with high cardiovascular risk like those studied in ACCORD are treated to blood sugar levels as low as those tested in this study."

She also warned that:

"People with diabetes should never adjust their treatment plan or goals without consulting their health care providers."

The actual A1C levels attained in the intensive treatment group in the ACCORD study were on average lower than the standard treatment group, with half of the intensive group reaching an average A1C level of below 6.4 per cent, and half of the standard group reaching below 7.5 per cent. In both groups the levels were lower than when they started the trial.

NHLBI project officer for ACCORD and a member of the ACCORD steering committee, Dr Denise G Simons-Morton said:

"ACCORD is an important study intended to find new answers to help people with type 2 diabetes reduce their high risk of heart disease."

"Hypotheses about treatments to prevent cardiovascular disease in people with type 2 diabetes need to be tested in clinical trials such as ACCORD. The ACCORD results, along with results from other studies, will contribute to determining what the treatment goals should be in patients with various characteristics," she added.

The ACCORD researchers have not been able to establish a specific cause of the increased deaths in the intensive treatment group. According to the data they have analysed, there is no evidence that medication is responsible they said.

Both intensive and standard groups were treated using a range of diabetes medications such as: thiazolidinediones (TZDs, primarily rosiglitazone), metformin, insulins, sulfonylureas, exanatide, and acarbose.

One drug in particular was scrutinized in detail, the thiazolidinedione rosiglitazone, which has been the subject of much concern recently. The researchers conducted a specific review of this drug and found no link between its use and raised risk of death. Rosiglitazone is marketed by GlaxoSmithKline as Avandia.

It is estimated that 21 million Americans have diabetes and over 284,000 die from it every year, 65 per cent from cardiovascular related causes. A person with type 2 diabetes has a 2 to 4 times higher risk of heart attack than a healthy person.

Click here for more information on the ACCORD trial.

Source: NHLBI press release, ACCORD trial website.

Written by: Catharine Paddock, PhD


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