Evaluation of New WHO Diagnostic Criteria for Diabetes on the Prevalence of Abnormal Glucose Tolerance in a Heterogeneous Nepali Population - The Implications of Measuring Glycated Hemoglobin

N Baral, BC Koner, P Karki, C Ramaprasad, M Lamsal, S Koirala
Correspondence: Dr Nirmal Baral, nirmalbaral@hotmail.com

ABSTRACT
Aim of the Study The present study was designed to (a) evaluate the implications of revised WHO diagnostic criteria on prevalence of abnormal glucose tolerance, (b) compare glycated hemoglobin level amongst healthy, impaired glucose tolerance (IGT), impaired fasting glucose (IFG) and diabetic subjects and (c) evaluate the assay of glycated hemoglobin in screening IGT, IFG from normal subjects.
Methodology Hospital based, cross-sectional study. Plasma glucose and glycated hemoglobin (gHb) were estimated by glucose oxidase and affinity chromatography method respectively.
Results The crude prevalence of IFG, IGT and diabetes were 9%, 18% and 5.29% respectively with no significant difference between Mongol and non-Mongol population. Newly introduced IFG group falsely incorporate 12% diabetic subjects and fails to detect 83% IGT subjects as impaired glucose metabolism. The gHb level is raised in IGT and diabetic group but not in IFG group.
Conclusion The assay of gHb may be used to screen abnormal glucose tolerance but paired estimation of fasting glucose increases the reliability of diagnosis. The level of gHb in mild carbohydrate intolerance mostly depend on the level of rise in post prandial glucose (where the variation is wide, as in IGT) but not on the narrow variance in fasting plasma glucose level as found in IFG.

Keywords: Glycated hemoglobin (gHb), Impaired fasting glucose (IFG), Diabetes mellitus, Impaired glucose tolerance (IGT)
Singapore Med J 2000; 41(6): 264-267