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 7.0mmol/l in contrast with the current World Health Organisation criteria of 2 hour glucose concentration 11.1mmol/l.
Design: Data were collected from 13 populations and three occupational based studies from eight European countries. All studies used a 75g oral glucose tolerance test to measure fasting and 2 hour glucose concentrations.
Subjects: 17881 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.
- The new diagnostic criteria for diabetes recommended by the American Diabetes Association in 1997 will increase the prevalence of diabetes from 7.2% to 7.7% in European populations
- In elderly groups with a high prevalence of diabetes the increase in prevalence would be substantially higher
- Among 17881 men and 8309 women, 1517 were classified as having diabetes according to either the American or WHO criteria
- Among these 1517 only 28% were classified as having diabetes according to criteria of both organisations
- An analysis of existing prospective data on the prognostic impact of the new criteria should be performed before a decision is made on changing the diagnostic criteria