PHILADELPHIA — Testing for hemoglobin A1c could be an effective means of screening children not only for type 2 diabetes but also for impaired glucose tolerance, according to the results of a study of 74 children.
“Type 2 diabetes was effectively excluded by hemoglobin A1c [HbA1c] below 6.0%,” said Dr. Alisa Schiffman of Children's Hospital of Philadelphia. Using this cutoff, HbA1c was 100% sensitive and 80% specific in identifying children with type 2 diabetes.
In its 2008 position statement on the standards of medical care in diabetes, the American Diabetes Association stated that the fasting plasma glucose test is the preferred means to diagnose diabetes in children and in nonpregnant adults. The use of the Hb A1c level for the diagnosis of diabetes is not recommended at this time (Diabetes Care 2008;31:S12–54).
However, “oral glucose tolerance tests and fasting plasma glucose have logistical challenges in children” because of the overnight fasting requirement and multiple blood draws, Dr. Schiffman said at the annual meeting of the Eastern Society for Pediatric Research.
HbA1c testing can be performed with just a finger stick at any time of day regardless of fasting status.
The researchers performed a retrospective chart review of 74 children (mean age 12 years) who were referred for the evaluation of type 2 diabetes. The children were assigned to one of three groups based on their fasting plasma glucose level and 2-hour plasma glucose level.
There was a significant trend for increasing HbA1c along the continuum from normal glucose tolerance to type 2 diabetes. Mean HbA1c was 5.4% for those with normal glucose tolerance, 6.1% for those with impaired glucose tolerance, and 6.8% for those with type 2 diabetes.
A threshold HbA1c of 5.7% was 91% sensitive and 80% specific in identifying children with abnormal glucose tolerance.
“Hemoglobin A1c can be used to screen for type 2 diabetes and even impaired glucose tolerance [in children],” said Dr. Schiffman.
Likewise, there was a significant trend for decreasing mean β-cell function along the continuum from normal glucose tolerance to impaired glucose tolerance to type 2 diabetes.
Children with normal glucose tolerance had a fasting plasma glucose level less than 100 mg/dL and a 2-hour plasma glucose less than 140 mg/dL. Children with impaired glucose tolerance had a fasting plasma glucose level between 100 mg/dL and 126 mg/dL and a 2-hour plasma glucose between 140 mg/dL and 200 mg/dL.
Children with type 2 diabetes had a fasting plasma glucose level of at least 126 mg/dL and a 2-hour plasma glucose greater than 200 mg/dL. In all, 51 children had normal glucose tolerance, 16 had impaired glucose tolerance, and 7 had type 2 diabetes.