Revised Criteria for Diagnosing Diabetes - Rational or Not ?

In 1985 World Health Organization (WHO) recommended fasting plasma glucose (FPG) ≥7.8 mmol/L or 2 hour post-challenge plasma glucose (2-h PG) ≥11.1 mg/dL as the criteria for diagnosing diabetes. In 1997, American Diabetes Association (ADA) proposed to use only FPG and lowered the threshold from 7.8 to 7 mmol/L. The objectives of this retrospective study were to compare the two criteria in the categorization of diabetes and to evaluate and compare different diagnostic cutpoints defined only by either FPG or 2-h PG. A total of 1421 oral glucose tolerance tests (OGTT) (457 men, 964 women; mean age 50.9 ± 12.8 years, rangeâ 18- 87 years) performed for subjects at different stages of hyperglycemia were rewieved. According to ADA and WHO criteria 9.5% and 16.9% of patients had diabetes mellitus, respectively. The overall ќ which measures the agreement between the two classification systems was poor (ќ=0.21). The optimal cut-off value for FPG to identify diabetic subjects as diagnosed with OGTT was between 6.5 mmol/L (50% sensitivity, 85% specificity) and 7.1 mmol/L (>95% sensitivity, 23% sensitivity). Our results show that, the subjects defined by FPG, does not cover the same subjects obtained from the 2-h PG and there are significant overlaps and discordances between ADA and WHO criteria.