Clarity on control (American Diabetes Assn. Scientific Sessions)

The ADA plans to roll out a new method of reporting hemoglobin A1c results -- one it hopes will be easier for patients to understand.

By Amy Snow Landa — Posted Aug. 6, 2007

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When you tell a patient her hemoglobin A1c result is 8%, how does she relate that number to the blood glucose levels she measures at home in units of mg/dL? Is an A1c of 8% equivalent to an average glucose of 180?

As if diabetes management isn't complicated enough, dealing with different types of blood glucose measures can make it more so.

The American Diabetes Assn. hopes that a new method of reporting A1c results will help clear up the confusion.

The ADA plans to begin encouraging physicians later this year to tell patients their A1c results in "average glucose" units that are the same units patients use in self-monitoring.

The idea is to make it easier for patients to understand their A1c results by reporting them in units that are familiar, said Richard Kahn, PhD, the ADA's chief medical and scientific officer.

It should make the physician's job easier as well, Dr. Kahn said during a news conference at the ADA's annual scientific sessions June 22-26 in Chicago.

"It's just too complicated to explain to someone what a hemoglobin of 7% means and how it relates to [his] 140, 150, 180," he said. "It's so much easier to say to someone they've got an average glucose of X."

Waiting for trial results

But before rolling out its new initiative, the ADA is waiting for the final results of an international clinical trial aimed at determining whether hemoglobin A1c accurately reflects average blood glucose.

Reporting A1c results in average glucose units requires certainty about the correlation between the two numbers, explained David M. Nathan, MD, director of the Diabetes Center and the General Clinical Research Center at Massachusetts General Hospital and professor of medicine at Harvard Medical School.

That certainty has been elusive in the past, Dr. Nathan said. Previous studies were based on infrequent glucose monitoring, which meant there was a possibility of sampling error. So researchers weren't sure if an A1c of 5% represented a blood sugar of 80, 90 or 100, or if an A1c of 10% was a 200, 250 or 300, he said.

But the ADA, in cooperation with the European Assn. for the Study of Diabetes and the International Diabetes Foundation, is finishing up a clinical trial that may eliminate that uncertainty for good.

The International A1c-AG Study involves 10 diabetes centers in the United States, Europe and Africa that have recruited more than 600 diabetic and nondiabetic patients of various races and ethnicities. Researchers use continuous glucose monitoring and frequent finger sticks to measure average glucose levels over four months and compare them with patients' A1c levels.

Final results will be announced in September. But the preliminary findings, reported at the ADA meeting, are very encouraging, Dr. Nathan said. "As we had thought, based on incomplete evidence in the past, in fact there is a tight correlation between average blood glucose and hemoglobin A1c results. And we can use that tight correlation to provide a transformation of the A1c value into an actual blood glucose."

Assuming that the preliminary results hold up, the ADA, EASD and IDF will convene a committee in late summer or early fall to draft a template for converting A1c results to average glucose units.

But it won't be an overnight transformation. It will take time to recalibrate lab machines to produce A1c results in the new units. In the meantime, the ADA plans to offer a "cheat sheet" to help doctors convert A1c percentages into average glucose units, Dr. Kahn said.

Doctors and patients also can choose to stick with the current system, Dr. Kahn said. Even after the machines are recalibrated, doctors still will get a printout that includes the A1c as a percentage. "So if you have a reluctant patient who says, 'I don't want to know what my average is, I want to know what my A1c is,' then the physician will have it."

But both Dr. Kahn and Dr. Nathan predict that over time most patients and doctors will realize how much easier it is to track average glucose.

And that should help improve patients' management of their diabetes, Dr. Nathan said. "To have the average level given as the same units as their everyday measurements just seems to me inherently a good thing."

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Diabetes: A runaway train

The prevalence of diabetes did not increase between 1975 and 1990, but it has risen 5% annually since 1990 and shows no signs of slowing down.

Researchers identified three distinct periods in the rate of existing diabetes in the population.

1963-1975: Prevalence increased from 13.6 to 25.8 per 1,000 people, 5.1% per year.

1975-1990: Prevalence did not increase.

1990-2005: Prevalence increased substantially from 26.4 to 54.5 per 1,000, 4.6% per year.

Though researchers cannot point to specific explanations for these changes, some things are clear.

1975: The first standard diagnostic criteria for diabetes were released and could be responsible for some stabilization in the rates.

1986: Obesity rates began to rise rapidly, contributing significantly to the climb in diabetes beginning in 1990.

Source: "Long Term Trends in the Prevalence and Incidence of Diagnosed Diabetes," from the National Health Interview Survey, ADA abstract number 125-OR

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Initiating insulin: Different views

A recent survey conducted by researchers from Eli Lilly and the University of Michigan polled 505 U.S. primary care physicians who participate in the Harris Interactive Physician Panel. All respondents see at least 10 patients with type 2 diabetes per week, and nearly a quarter see 60 or more a week. Their responses reveal a divide in opinions regarding the initiation of insulin therapy.

Opinion Disagree to strongly disagree Agree to strongly agree
Patients on insulin monitor blood glucose with sufficient frequency 40% 43%
Hypoglycemia risk makes physicians reluctant to prescribe insulin for patients older than 85 35% 43%
Diabetes patients eventually will need to go on insulin even if they are adherent to a diabetes regimen 41% 39%
Patients will not need to go on insulin if they follow physicians' recommendations 36% 40%
Training in insulin use is too time-consuming for staff 38% 40%

Source: ADA Abstract 112-OR

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Unraveling the complexities of insulin intervention

Faced with an ever-widening epidemic of type 2 diabetes, leading diabetes experts are urging physicians to pursue aggressive treatment, including early initiation of insulin, to bring hemoglobin A1c levels below 7%.

But they also acknowledge that major hurdles still must be overcome in convincing doctors and patients that the advantages of insulin therapy outweigh the disadvantages.

Traditionally, insulin has been considered a last option for controlling type 2 diabetes, so moving it up to a primary therapy requires a major shift in thinking.

Many patients fear insulin and are unwilling to use it as part of their treatment regimen if alternatives exist. Physicians also are reluctant in some cases to introduce insulin because of its complexity and additional self-care requirements.

Nevertheless, insulin remains the most potent drug for reducing blood glucose levels and should be considered an early treatment option for type 2 diabetes, said David M. Nathan, MD, director of the General Clinical Research Center and of the Diabetes Center at Massachusetts General Hospital and a professor at Harvard Medical School in Boston.

For some patients, insulin therapy may be indicated as early as diagnosis or shortly thereafter, Dr. Nathan said. He spoke during a symposium on insulin initiation in type 2 diabetes that was held at the American Diabetes Assn. Scientific Sessions June 22-26 in Chicago. The session attracted an overflow audience of physicians and other health care professionals.

Dr. Nathan walked the audience through a treatment algorithm for type 2 diabetes -- heavily weighted toward insulin therapy -- that was published as a consensus statement in 2006 by the ADA and its European counterpart.

Dr. Nathan, who chaired the expert panel that produced this document, pointed to studies showing that insulin, when combined with metformin, is more powerful than oral medications and can reduce A1c levels by about 2.5%.

Physicians also need to make sure that patients on insulin are getting adequate amounts of it, he said. "For primary care audiences, I tell them, 'I don't care exactly how you give the insulin as long as you give enough.' ... We tend to undertreat these patients."

He also urged doctors to try to reduce patients' anxiety about insulin therapy. Too often patients are told that if they don't lose weight, they'll have to go on insulin, he said. "If we stop threatening our patients with insulin, maybe they'll stop being so scared of it."

Drawbacks remain

But there also are significant downsides to using insulin therapy, said Robert R. Henry, MD, professor of medicine at the University of California at San Diego and director of the Center for Metabolic Research at the Veterans Administration Medical Center in San Diego.

Although many in his practice are treated with insulin, patient resistance can be a major barrier, he said. Studies have found that up to a quarter of patients with type 2 diabetes refuse this approach. "Some people will accept it without much problem at all, but others will try to do anything to get away from using insulin."

Another issue, particularly for primary care doctors, is the complexity and variety of these regimens. "Things are changing so rapidly, even with insulin, that it really takes specialized folks to use insulin," he said.

Some practices also do not have the necessary resources and staff to move patients successfully onto insulin.

Dr. Henry noted that the consensus algorithm, including its insulin therapy recommendations, is extremely complex and time-consuming.

"The intensive insulin treatment algorithm, I think, is an excellent algorithm for the knowledgeable diabetes care provider who has ample resources for patient education and close patient follow-up," he said. "I think it's impractical, though, and of modest, and perhaps minimal, clinical value for the majority of diabetes care providers with little in-depth knowledge of diabetes or the resources or the time to institute this complex algorithm."

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External links

Information about lectures, presentations and other developments at the 2007 American Diabetes Assn. Scientific Sessions (link)

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