Fasting plasma glucose and HbA1c as risk factors for Type 2 diabetes.
OBJECTIVE
We examined the value of combining fasting plasma glucose (FPG) and glycated haemoglobin (HbA(1c)) as a predictor of diabetes, using the new American Diabetes Association (ADA) criteria of FPG and lower cut-off point of HbA(1c).


METHODS
A retrospective cohort study was conducted from 1998 to 2006, inclusive, in 10 042 persons (55 884 person-years), with a mean age of 53.0 years at baseline. The cumulative incidence of diabetes (defined either as an FPG > or = 7.0 mmol/l or as clinically diagnosed diabetes) was measured.


RESULTS
The cumulative incidence and incidence density of diabetes were 3.7% (368 cases) and 6.6/1000 person-years over a mean follow-up period of 5.5 years. The cumulative incidence of diabetes in subjects with impaired fasting glucose (IFG) and HbA(1c) 5.5-6.4% was 24.8% (172/694 persons) compared with 0.4% (25/6698 persons), 2.5% (15/605 persons), 7.6% (156/2045 persons) in those with normal fasting glucose (NFG) and HbA(1c) < 5.5%, NFG and HbA(1c) 5.5-6.4% and IFG and HbA(1c) < 5.5%, respectively. The hazard ratio for diabetes, adjusted for possible confounders, was 7.4 (95% confidence interval, 4.70 to 11.74) for those with NFG and HbA(1c) 5.5-6.4%, 14.4 (11.93 to 27.79) for those with IFG and HbA(1c) < 5.5% and 38.4 (24.63 to 59.88) for those with IFG and HbA(1c) 5.5-6.4%.


CONCLUSIONS
The combination of FPG and HbA(1c) identifies individuals who are at risk of progression to Type 2 diabetes at the new ADA criteria of FPG and a lower cut-off point of HbA(1c) than previous studies.
Inoue
Kazuo
K
Department of Public Health, Graduate School Medicine, University of Tokyo, Tokyo, Japan. inouek@m.u-tokyo.ac.jp
Matsumoto
Masatoshi
M
Akimoto
Kimihiko
K
D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000453:epidemiology; D005215:Fasting / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012015:Reference Standards; D012189:Retrospective Studies; D012307:Risk Factors
D001786:Blood Glucose; D006442:Glycated Hemoglobin