Will New Diagnostic Criteria for Diabetes Mellitus Change Phenotype of Patients with Diabetes? Reanalysis of European Epidemiological Data. DECODE Study Group on Behalf of the European Diabetes Epidemiology Study Group

Objective: To evaluate the impact of the revised diagnostic criteria for diabetes mellitus adopted by the American Diabetes Association on prevalence of diabetes and on classification of patients. For epidemiological purposes the American criteria use a fasting plasma glucose concentration >=7.0 mmol/l in contrast with the current World Health Organisation criteria of 2 hour glucose concentration >=11.1 mmol/l.

Design: Data were collected from 13 populations and three occupational based studies from eight European countries. All studies used a 75 g oral glucose tolerance test to measure fasting and 2 hour glucose concentrations.

Subjects: 17 881 men; 8309 women; age range 17-92 years.

Main Outcome Measures: Classification of diabetes according to both sets of criteria.

Results: The application of the American criteria on European populations induced changes in prevalence of diabetes ranging from a reduction of 4.0% to an increase of 13.2%. A total of 1517 previously undiagnosed individuals had diabetes according to either the WHO or the American criteria. Among 1044 with diabetes according to American criteria, only 45% had 2 hour values fulfilling the WHO criteria. The risk of disagreement of classification decreased with increasing body mass index (P<0.00001) and increasing age (P<0.0001); the impact of sex was not significant (P=0.08).

Conclusions: This shift in strategy from using 2 hour to fasting plasma glucose will cause an increase in the prevalence of diabetes in some European populations. A high degree of disagreement in the classification was observed between the two recommendations. Prospective data are needed to evaluate whether the WHO or the American criteria best identify individuals at risk of developing microvascular complications and cardiovascular disease. Wider implementation of revised diagnostic criteria should await prospective data.