Lowering the Criterion for Impaired Fasting Glucose

Lowering the Criterion for Impaired Fasting Glucose Impact on disease prevalence and associated risk of diabetes and ischemic heart disease E. Shyong Tai , MB, CHB 1 2 , Su Yen Goh , MB, BS 1 , Jeannette J.M. Lee , MB, BS 2 , Moh-Sim Wong , MB, BS 3 , Derrick Heng , MB, BS 4 5 , Kenneth Hughes , PHD 6 , Suok Kai Chew , MSC 4 , Jeffery Cutter , MSC 4 , William Chew , MB, BS 3 , Ken Gu , PHD 5 , Kee Seng Chia , MD 2 and Chee Eng Tan , PHD 1 2 1 Department of Endocrinology, Singapore General Hospital, Singapore 2 NUS-GIS Centre for Molecular Epidemiology, National University of Singapore, Singapore 3 Department of Medicine, Alexandra Hospital, Singapore 4 Epidemiology and Disease Control Division, Ministry of Health, Singapore 5 Clinical Trials and Epidemiology Unit, National Medical Research Council, Singapore 6 Department of Community, Occupational and Family Medicine, National University of Singapore, Singapore Address correspondence and reprint requests to Dr. E. Shyong Tai, Department of Endocrinology, Block 6 level 6, Room B35, Singapore General Hospital, Outram Road, Singapore 169608, Republic of Singapore. E-mail: eshyong{at}pacific.net.sg Abstract OBJECTIVE —To determine the effect of lowering the fasting plasma glucose (FPG) criterion for impaired fasting glucose (IFG) on the prevalence of IFG, the risks of diabetes, and cardiovascular disease (CVD) associated with IFG. RESEARCH DESIGN AND METHODS —Three studies were used: 1 ) the 1998 National Health Survey (NHS98), a randomly selected cross-sectional sample of 4,723 subjects; 2 ) the Singapore Impaired Glucose Tolerance (IGT) Follow-up Study, a cohort study comprising 295 IGT and 292 normal glucose tolerance subjects (frequency matched for age, sex, and ethnic group) followed up from 1992 to 2000; and 3 ) the Singapore CVD Cohort Study, comprising 5,920 subjects from three cross-sectional studies in whom the first ischemic heart disease (IHD) event was identified through linkage to registry databases. Risk of diabetes (Singapore IGT Follow-up study) was estimated using logistic regression adjusted for age, sex, and ethnicity. Risk of IHD (Singapore CVD cohort) was estimated using stratified (by study, from which data were derived) Cox’s proportional hazards models adjusted for age, sex, and ethnicity. RESULTS —Lowering the criterion for diagnosing IFG to 5.6 mmol/l increased the prevalence of IFG from 9.5 to 32.3% in the NHS98. The lower cutoff identified more subjects at risk of diabetes and IHD,