Pre-diabetics have high risk of all-cause mortality
Pre-diabetics have high risk of all-cause mortality
Soaring medical expenses should alert caretakers
Citing studies that show mortality from all causes rises steadily in the years before a patient is diagnosed, researchers are recommending early diagnosis more strongly than ever.
Johns Hopkins researchers told health care professionals at the American Diabetes Association Scientific Sessions in San Diego in June, that all-cause mortality for patients with impaired glucose tolerance (IGT) was 42% higher than in patients with normal blood glucose levels. The risk of death for those with undiagnosed diabetes was 177% greater and 211% greater in those with diagnosed diabetes.
"This makes it critically important that doctors identify people with abnormal blood glucose levels, especially those with undiagnosed diabetes," says Frederick L. Brancati, MD, associate professor of medicine and epidemiology at Johns Hopkins University School of Medicine in Baltimore.
Those figures make Brancati think that across-the-board HbA1c testing should be the standard for screening. "That’s where the rubber meets the road," he says. However, he warns, there are many patients who "fall through the cracks" and suggests that HbA1c levels may be "insufficiently sensitive" to identify some IGT patients. For that reason, Brancati looks for a resurgence in the use of the two-hour glucose tolerance test.
"We probably lose [more diagnoses] than we capture by not doing the GTT. It cuts out a lot of people who may have OK fasting sugars, but still be impaired," says Brancati. "I know it is difficult and time-consuming to do, and it is uncomfortable for the patient. That’s probably why it isn’t done very often." he says. "There is a progressively rising risk of death as glucose tolerance worsens, and this risk is independent of established risk factors for cardiovascular disease."
His team also found that 35% of all American die by the age of 75, but for those with impaired glucose tolerance, 42% die by the age of 75 — 52% of those with undiagnosed diabetes and 77% of those with diagnosed diabetes.
Brancati explains the higher mortality rate among diagnosed patients: Many patients with diabetes go undiagnosed for years, and by the time they are diagnosed, complications like cardiovascular disease and nephropathy have already set in, bringing with them them increased risk of death.
Researchers at Kaiser Permanente’s Northwest Region Center for Health Research in Portland, OR, have found that glucose tolerance-impaired patients have steadily rising medical costs in the eight years prior to a diagnosis of Type 2 diabetes.
Gregory A. Nichols, PhD, a senior research assistant at Kaiser, stops short of saying rising medical costs should be a marker for increasing insulin sensitivity, but says, "It could be an alert that maybe diabetes is one of the things we ought to look at."
He says he believes Kaiser’s registry containing data on 35,000 diabetics since 1988 is the longest running diabetes registry in the world.
Looking at data from that registry, Nichols found that patients with IGT had significantly lower all-cause medical costs than diagnosed diabetics or even nondiabetic control eight years prior to diagnosis. But those costs began to steadily creep upward. Six years before diagnosis, IGT patients cost 25% more than controls and 22% more than diagnosed diabetics.
IGT and cost of care
The figures became even more telling three years before diagnosis, when IGT patients cost 2.8 times as much as controls and 2.1 times as much as diagnosed diabetics.
By the year before diagnosis, IGT patients spent a whopping $8,685 in health care costs, 4.5 times the cost of control ($1,949) and 3.1 times the amount spent by diagnosed diabetics ($2,819). Costs were determined in 1993 dollars.
Nearly half (43%) of pre-diagnosis costs were cardiovascular related, Nichols says. "In a large part, these costs are driven by efforts to manage cardiovascular risk factors and cardiovascular disease." This substantiates other theories that cardiovascular complications of diabetes may get a foothold long before a patient is diagnosed.
"We are only now beginning to understand the longitudinal costs of diabetes after recognition," says Nichols. "Yet this is the first study that has looked at costs prior to recognition."
All of this comes despite what Nichols thinks is a comparatively early diagnosis tradition at Kaiser Northwest with an average HbA1C of 7.6% among its diagnosed diabetic patients.
"Our diabetes program is very aggressive, and because our medical care is comprehensive, we think we’re finding diabetes earlier than in the general population," he says.
Nichols adds, "Certainly, I think the research is all increasingly clear that control is a good thing. I am surprised there was ever a question about it."
Nichols and his team are currently studying what he calls a dramatic jump in health care costs among diabetic patients in the first two years after diagnosis.
A major multicenter trial, the Diabetes Prevention Program, is currently under way to determine whether early treatment can prevent or delay the onset of diabetes in people with IGT and whether lifestyle modification or drug therapy is the best approach.
[For more information, contact Frederick Brancati at (410) 955-9843 and Gregory Nichols at (503) 335-6733.]
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