The effect of the down regulation of diagnostic criteria for impaired fasting glucose on the detection rate of the impaired glucose regulation subjects

Objective To analyse the effect of the down regulation of diagnostic criteria of impaired fasting glucose on the detection rate of impaired gluose regulation subjects, and to investigate the optimal FPG cut-point for normal and abnormal glucose metabolism. Methods A total of 2882 subjects without history of type 2 diabetes mellitus(T2DM) received oral glucose tolerance test (OGTT). The 1997 and 2003 ADA diabetes diagnostic criteria were used for analysis. Results (1)After the low limit for IFG was decreased from 6.1 to 5.6 mmol/L, the isolated IFG(I-IFG) subjects increased by 367 cases. Meanwhile the IFG subjects increased from 424 to 1032 cases, and the IGT subjects combining IFG increased from 243 to 484 cases. In all IGT subjects, the IGT subjects combining IFG increased from 34% to 68%. (2)The newly increased I-IFG population had higher levels of BMI, FPG, HbA_1c, TG and TC (all P0.01) and a higher prevalence of overweight (P0.01) as compared with those in NGT. (3) The optimal FPG cut-point relative to impaired glucose tolerance (IGT)(7.8≤2 hPG11.1 mmol/L) was 5.6 mmol/L in non-DM subjects. Conclusions After the low limit for IFG is decreased, the IFG and IFG plus IGT subjects increase significantly. In newly increased I-IFG subjects, the metabolic abnormalities of glucose and lipid occur. In non-DM subjects the optimal FPG cut-point for IGR is 5.6 mmol/L.