Low yield of population-based screening for Type 2 diabetes in the Netherlands: the ADDITION Netherlands study

Background. About 10 years ago, it was estimated that half of all people with diabetes were unrecognized. Since then, according to the national guidelines, case finding for diabetes in general practice has become common in the Netherlands, resulting in a substantial increase of the prevalence of known diabetes. Nevertheless, the need for population-based screening is advocated, especially by the national federation of diabetes patients. Objective. To evaluate the efficiency of population-based screening for Type 2 diabetes. Methods. From 2002 to 2004, we performed a four-step screening procedure [questionnaire, random glucose measurement, fasting glucose measurement and oral glucose tolerance test (OGTT)] and a three-step procedure (without random glucose measurement) in 79 general practices in the southwestern region of the Netherlands. Results. A total of 56 978 non-diabetic subjects, aged 50-70 years, were asked to complete the questionnaire. Those with a score above threshold underwent further glucose testing. Eventually, 586 participants (1.0%) were diagnosed with Type 2 diabetes (in four-step procedure 285 subjects and in three-step procedure 301). Impaired glucose regulation was assessed in 1011 participants (1.8%). Dropout rate in the screening programme among participants who should undergo an OGTT was 23.4%. The risk score was higher if glucose metabolism was more disturbed. Conclusion. In the Netherlands, the yield of population-based screening is low. The dropout among high-risk individuals was high. Given the decreasing prevalence of undiagnosed diabetes and the possibility of opportunistic screening on a continuous basis, opportunistic screening for diabetes might be more appropriate than population-based screening. Further research on this topic is needed.