ESTES PARK, COLO. — A 2-hour oral glucose tolerance test is far more sensitive than the standard fasting blood glucose test in identifying obese children at increased risk for type 2 diabetes or metabolic syndrome.
Results of a recent Canadian study indicated that the current American Diabetes Association recommendation for prediabetes screening of obese children needed to be overhauled, said Dr. Walter L. Larimore, a Monument, Colo., family physician, at the annual conference of the Colorado Academy of Family Physicians.
The ADA recommends using the fasting blood glucose (FBG) test to screen obese children aged 10 years and older. But a study presented at the annual meeting of the Endocrine Society by Dr. Katherine Morrison of McMaster University, Hamilton, Ont., casts doubt upon that practice.
The study involved 173 obese children aged 5-17 years. With the FBG test alone, only 9% met the diagnostic criteria for prediabetes, compared with 24% of those who were screened by both the FBG and 2-hour oral glucose tolerance tests. The ADA defines prediabetes as an impaired FBG of 100 mg/dL or greater, or an impaired glucose tolerance of at least 140 mg/dL.
“In other words, if we follow the current recommendation—which I'm certain will change—we'll miss almost three-quarters of the kids” who are prediabetic, Dr. Larimore said.
Moreover, the current recommendation is to screen obese children at age 10 years and older. The yield in younger obese children has been thought to be too low to justify screening. But Dr. Morrison found that the prevalence of prediabetes in 5- to 9-year-olds in her study was 21%, similar to the 26% rate among those aged 10-17 years.
With the FBG test alone, 5% of screened children met International Diabetes Federation pediatric criteria for metabolic syndrome, compared with 13% when both screening tests were applied.
The 2-hour oral glucose tolerance test is more costly and inconvenient than obtaining an FBG level, but Dr. Larimore indicated that he is inclined, in light of the Canadian study, to make greater use of it in taking on the childhood obesity epidemic.
'If we followthe current recommendation—which I'm certain will change—we'll miss almost three-quarters of the kids.' DR. LARIMORE