Screening for type 2 diabetes. Lessons from the ADDITION-Europe study.

AIMS: To describe and compare attendance rates and the proportions of people identified with Type 2 diabetes mellitus in people with previously unknown diabetes who participated in screening programmes undertaken in general practice in the UK, Denmark and the Netherlands as part of the ADDITION-Europe study.
METHODS: In Cambridge, routine computer data searches were conducted to identify individuals aged 40-69 years at high risk of Type 2 diabetes using the Cambridge Diabetes Risk Score. In Denmark, the Danish Diabetes Risk Score was mailed to individuals aged 40-69 years, or completed by patients visiting their general practitice. In the Netherlands, the Hoorn Symptom Risk Questionnaire was mailed to individuals aged 50-69 years. In these three centres, high-risk individuals were invited to attend subsequent steps in the screening programme, including random blood glucose, HbA(1c) , fasting blood glucose and/or oral glucose tolerance test. In Leicester, eligible people aged 40-69 years were invited directly for an oral glucose tolerance test. In all centres, Type 2 diabetes was defined according to World Health Organization 1999 diagnostic criteria.
RESULTS: Attendance rates ranged from 20.2% (oral glucose tolerance test in Leicester without pre-stratification) to 95.1% (random blood glucose in opportunistic screening in Denmark in high-risk people). The percentage of people with newly detected Type 2 diabetes from the target population ranged from 0.33% (Leicester) to 1.09% (the Netherlands).
CONCLUSIONS: Screening for Type 2 diabetes was acceptable and feasible, but relatively few participants were diagnosed in all participating centres. Different strategies may be required to increase initial attendance and ensure completion of screening programmes.