No Easy Cure for Diabetic Children
By RON WINSLOW
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The only pill approved in the U.S. for treatment of children with type 2 diabetes is proving surprisingly ineffective, according to a new study, heightening worries about the fast-growing and largely preventable disease.
The research, reported Sunday, is one of the first long-term studies to test the effectiveness of drugs for diabetic children—estimated in the U.S. to number in the tens of thousands. It tested three different drug-based regimens aimed at controlling the disease and found that only about half the participants successfully controlled their blood sugar—despite relatively good compliance.
Researchers said the findings suggested a majority of youth with the disease may require more than one oral medication—or resort to insulin injections—within a few years of diagnosis.
The disappointing results, some of which caught researchers by surprise, underscore the daunting challenges in treating the condition, which had been viewed as an adult disease until it emerged among adolescents in the past 15 to 20 years alongside rising rates of obesity.
Obesity hinders the way the body regulates blood sugar, contributing to development of type 2 diabetes and making the illness largely preventable by maintaining proper body weight through diet and exercise.
The study suggests the message for families with children at risk of becoming obese is to work to prevent the onset of obesity much earlier in childhood.
"It would be much better if these kids didn't get diabetes in the first place," said Phil Zeitler, professor of pediatrics at the University of Colorado Denver and Children's Hospital Colorado, who led the study. "It's a bad disease when they get it."
Dr. Zeitler presented the findings Sunday at a meeting of the Pediatric Academic Societies in Boston. They also were published online by the New England Journal of Medicine.
People with type 2 diabetes are at risk of heart attacks and strokes, kidney disease, blindness, amputations and infertility. Worries among youth are amplified because the risk of complications grows with the duration of the disease, researchers say.
The number of American children with type 2 diabetes isn't well established, but estimates by the U.S. Centers for Disease Control and Prevention from 2001 to 2005 suggest tens of thousands are affected and increasing by 3,600 annually. Minorities, including blacks and Hispanics, are at higher risk than white children, and girls are at higher risk than boys. The CDC says about 17% of Americans under age 20—or about 12.5 million people—are obese and at increased risk for type 2 diabetes.
Type 2 diabetes is distinct from the type 1 version, an autoimmune disorder in which the body doesn't produce insulin, the hormone that controls the level of sugar in the blood.
The study was sponsored by the National Institute for Diabetes and Digestive and Kidney Diseases and launched a decade ago after a dramatic surge of cases in the mid-1990s of children being diagnosed with type 2 diabetes.
One question researchers had was whether obesity was compounding an already known phenomenon in which resistance to insulin increases during adolescence, likely as part of the growing process. That caused researchers to wonder whether there was "value in treating these kids aggressively during that time and maybe they would end up later in adolescence in better shape," Dr. Zeitler said.
The study enrolled 699 children between 10 and 17 years old, essentially all of whom were obese and who had been diagnosed with type 2 diabetes for an average of eight months.
They were randomly assigned to one of three treatments: metformin, the mainstay diabetes medicine; metformin plus a lifestyle-intervention program; or metformin plus rosiglitazone, a diabetes drug marketed as Avandia by GlaxoSmithKline PLC. GSK +0.67%
After an average follow-up of nearly four years, 46% of the participants had failed to control blood sugar, meaning a measure known as HbA1c exceeded 8% for at least six months or that they had deteriorated and required insulin treatment. People are considered diabetic with sustained HbA1c levels above 6.5%; most diabetic patients seek to keep their levels below 7%.
By treatment, 52% of those on metformin alone had failed, compared with 47% on metformin plus lifestyle change and 39% on the two-drug regimen. Statistically, only the two-drug treatment was considered superior to metformin, researchers said. But marketing of rosiglitazone was sharply curtailed in the U.S. in 2010 after the drug was linked to an increase of heart attacks, curtailing its use in treatment.
Researchers were surprised that participants on metformin alone fared poorly. Half of the failures occurred within the first year of treatment.
"That's not the experience in the adult population," said Barbara Linder, senior adviser for childhood diabetes research at the NIDDK and a co-author. It was especially troubling, she said, because other than injections of insulin, metformin is the only diabetes treatment approved for use in children.
Other studies suggest adults fail on metformin therapy at a rate of just 8% to 12% a year, Dr. Zeitler said. But the good news, Dr. Zeitler added, is that in the study, many of the children who succeeded on the therapy for more than two years seemed to respond for a prolonged period.
The results prompted other experts to renew calls for societal efforts to combat diabetes and obesity among young people.
"Children 50 years ago did not avoid obesity and its complications by making healthy choices," said David B. Allen, professor of pediatrics and head of endocrinology at University of Wisconsin American Family Children's Hospital, Madison. "They simply lived in a more active and less calorie-laden environment."
The study suggests drugs aren't the answer, he said. Without new policies to encourage a healthy diet and more physical activity, "it's going to be impossible to turn this situation around," said Dr. Allen, who wrote an editorial that accompanied the study in NEJM.
For children who begin to fail on metformin, Dr. Zeitler said, the best option may be the one recommended by the American Diabetes Association: once-daily injections of insulin. Meantime, scientists need to test other medicines to combine with metformin to avoid or delay starting on insulin, but there aren't any other drugs currently approved for children.
Dr. Zeitler said children and their doctors should avoid adding one of a class of long-standing diabetes drugs called sulphonyureas, in part because they are associated with increased risk of extremely low blood sugar, or hypoglycemia.
Dr. Zeitler noted some positives. Half of the participants were able to maintain control on at least one of the regimens, and researchers plan to do further analysis to look for factors that might predict who responds to treatment. Girls did better on the two-drug regimen than boys; boys appeared to get more benefit from lifestyle changes.
Write to Ron Winslow at firstname.lastname@example.org