Gestational diabetes screening of a multiethnic, high-risk population using glycated proteins

In populations with a high incidence of gestational diabetes (GDM), any form of oral glucose testing for screening or diagnosis excessively strains the health care system. We investigated the value of glycated proteins as potential screening tests in 430 pregnant women, i.e. protein corrected fructosamine (cFRUC) and hemoglobin A1c (HbA(1c)) both alone and in combination for a GDM diagnosis confirmed by the 'gold standard' 100-g oral glucose tolerance test (OGTT). Two cut-off values were used for each test, the upper to rule in and the lower to rule out GDM. At the lower cut-off values for cFRUC of 210 micromol/l and HbA(1c) of 5%, the sensitivities achieved were 92.2 and 92.1% while the negative predictive values were 88.9 and 86.9%, respectively. The upper cut-off values did not achieve acceptable positive predictive values to be useful for ruling in GDM. Screening of our multiethnic, high-risk pregnant population with a combination of cFRUC and HbA(1c) on a single fasting sample would have avoided the cumbersome OGTT (by ruling out GDM) in 37.9% women with only a 3.9% misclassification rate. This potentially simpler approach, though not universally applicable, would be clinically useful and more acceptable to patients in selected high-risk populations.