Comparison of Clinical Characteristics of Impaired Fasting Glucose with Impaired Glucose Tolerance in Yonchon County

Jeong, In Kyong; Moon, Min Kyong; Kim, Sang Wan; Park, Young Joo; Kim, Sun Yuk; Shin, Chan Soo; Park, Do Joon; Park, Kyong Soo; Kim, Seong Yeon; Cho, Bo Youn; Kim, Noe Kyeong; Lee, Hong Kyu

Abstract

BACKGROUND: To compare the clinical characteristics of 1997 American Diabetes Association (ADA) impaired fasting glucose (IFG) based on fasting plasma glucose (FPG) with World Health Organization (WHO) impaired glucose tolerance (IGT) based on oral glucose tolerance test (OGTT) in a Korean population.
METHODS
The analyses were based on the data of 2,251 subjects aged 30-80 years obtained from the surveys of Yonchon County in Korea in 1993, and the data of 1084 subjects participated in the follow-up survey in 1995. Prevalence of glucose tolerance categories was obtained by using WHO and ADA criteria, and the level of agreement was estimated by index. Cardiovascular risk profile and the incidence of diabetes based on the ADA criteria after 2 years were compared by focusing on the discordant ctiagnostic categories namely IGT/NFS in which the subjects were diagnosed as IGT by WHO criteria but normal fasting glucose(NFG) by ADA criteria and NGT/IFG diagnosed as normal glucose tolerance(NGT) by WHO but IFG by ADA. Results The ADA criteria failed to diagnose 69% of IGT patients, that is 62% of them were considered normal and 7% as diabetes. The overall agreement was poor (x statistics = 0.32, p<0.05). Subjects classified into IGT/NFG or NGT/IFG showed the worse cardiovascular risk profile and higher incidence of diabetes than NGT/NFG. Especially, subjects with NGT/IFG exhibited higher incidence of diabetes than those with IGT/NFG.
CONCLUSION
Although IFG predicts subsequent development of diabetes much better than IGT, the vast majority of the subjects with IGT will be missed according to ADA criteria based on FPG only. Consequently FPG alone could be an inadequate substitute for the OGTT.