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ADA Scientific Meetings Address Glucose Control


Meetings focus attention on controlling glucose levels and cardiovascular disease



Issue: July 2008

By: Patrick L Shabram

The American Diabetes Association 68th Scientific Meetings drew nearly 20,000 attendees for the sessions held June 6-10, 2008, at the Moscone Center in San Francisco.  In addition to the presentation of research, the event offered colleagues the opportunity to meet and compare notes.  Locally, the UCSF Diabetes Center used the meeting as an opportunity to reconnect with UCSF alumnae, including ADA President Ann Albright, and to present special Lifetime Recognition awards to Gerold Grodsky, Ph.D. and Peggy Huang, R.N., C.D.E.

Far and away the most notable aspect of the sessions, however, was the presentation of results and discussions surrounding three separate studies on HbA1C control and its impact on cardiovascular events in type 2 diabetes patients.  The amount of attention given this topic may have been, in part, the result of a February media release linking higher death rates to intensive glucose control in one of the studies. This was often misinterpreted by the media as direct correlation between any kind of glucose control and increased risk of death.   

The three studies included the ADVANCED (Action to Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation), ACCORD (Action to Control Cardiovascular Risk in Diabetes) and VADT (Veterans Affairs Diabetes Trial of Blycemic Control and Complications in Diabetes Mellitus Type 2).  All three studies found intensive control of blood glucose beneficial to patients. The ACCORD and ADVANCED studies came to a very similar conclusion: while intense blood glucose control yields little to no reduction of major macrovascular events in type 2 diabetes patients, it does have a significant impact on reducing microcardiovascular diseases.

“Overall, we found that the intensive (glucose) control strategy reduced the combined risk of macrovascular and microvascular complications by 10%, but that was driven largely by microvascular results,” said Anushka Patel, M.B.B.S., S.M., Ph.D., study director of the ADVANCE trial, and director Cardiovascular Division, The George Institute for International Health, in a press release.  “Further, the 14% reduction in microvascular risk was driven mainly by nephropathy rather than retinopathy.  We found that intensively controlling blood glucose reduces risk of the development or progression of kidney disease by 21%.”

The VADT study came to similar conclusions, treating, on average, the highest risk patients of the three studies.  The VADT study found some reduction between an intensive control group and a standard control group, but the results where statistically insignificant.  Analysis of the VADT study also suggested that intensive glucose control at the time of diagnosis of type 2 diabetes may help reduce cardiovascular risk; however that such treatment for patients long diagnosed with the disease has benefits for microvascular complications but not for reducing the risk of cardiovascular death.  “If you go into a population that already has multiple risk factors – or prior CVD – and longstanding poor glucose control, you cannot expect benefits from glucose control in the short term,” said William Duckworth, M.D., director of research, Carl T. Hayden VA Medical Center in Phoenix; Professor of Clinical Medicine, University of Arizona; and co-chair of the trial.

Despite finding no benefit to glucose control and cardiovascular death, all three studies found the overall number of major cardiovascular events to be lower than expected, due in large part to control of blood pressure and lipid control, combined with improved diet and exercise.  Even the “intensive arm” of the ACCORD study, which was suspended in February due to higher death rates than patients in the standard control group, did not find death rates from cardiovascular events higher than expected. 

The ACCORD study, which had the more intensive glucose lowering objective of the three studies, achieving a median A1C level of 6.4% in its intensive group, did find patients in their intensive group had a 22% higher relative risk of death compared to the standard group, which translated into an absolute mortality increase of about 1% during the average 3.5 years of treatment and follow up.  Discussions on the higher death rate at the ADA Scientific Sessions suggested that the increase in death rates was attributable in large part to increased risk of hypoglycemia.

As a follow up to the three studies, a group of panelist discussed the implications and came to strong consensus on several points:

1)      Type 2 diabetes patients should achieve a target for lowering and controlling glucose levels, doing so slowly, but eventually.

2)      Patients should begin controlling glucose levels upon diagnosis.

3)      Patients must maintain good blood pressure and lipid control to reduce the risk of cardiovascular events.

Furthermore, most panelists agreed that the ADA does not need to revise its guidelines for glucose control.  Specifically pointing to the reduced death rates, including the lower than expected cases of cardiovascular events within the study groups, several panelist noted that the current guidelines on blood pressure control, lipid control, diet, and exercise is working.  As such, levels for glucose control do not need to be revised, at least in the short term, until further analysis of the three studies, follow up study, and further clinical trials can be conducted.  Only Robert Rizza, M.D., Director of Research at Mayo Clinic in Rochester, Minnesota, suggested guidelines for glucose control should be moved downward slightly.