Objective: To investigate whether screening-detected diabetic patients differ from diabetic patients newly diagnosed in general practice with regard to the presence of microvascular complications.

Research and design methods: Diabetic patients, identified by a population-based _targeted screening procedure consisting of a screening questionnaire and a fasting capillary whole-blood glucose measurement followed by diagnostic testing, were compared with patients newly diagnosed with diabetes in general practice. Retinopathy was assessed with fundus photography, impaired foot sensitivity was assessed with Semmes-Weinstein monofilaments, and the presence of microalbuminuria was measured by means of the albumin-to-creatinine ratio (ACR).

Results: A total of 195 screening-detected type 2 diabetic patients and 60 patients newly diagnosed in general practice participated in the medical examination. The prevalence of retinopathy was higher in screening-detected type 2 diabetic patients than in patients newly diagnosed in general practice, but not significantly higher. The prevalence of retinopathy was 7.6% (95% CI 4.6-12.4) in screening-detected type 2 diabetic patients and 1.9% (0.3-9.8) in patients newly diagnosed in general practice. The prevalence of impaired foot sensitivity was similar in both groups, 48.1% (40.9-55.3) and 48.3% (36.2-60.7), respectively. The ACR was 0.61 (interquartile range 0.41-1.50) in screening-detected type 2 diabetic patients and 0.99 (0.53-2.49) in patients newly diagnosed in general practice. The difference in prevalence of microalbuminuria was not statistically significant. The prevalence of microalbuminuria was 17.2% (95% CI 12.5-23.2) and 26.7% (17.1-39.0) in screening-detected type 2 diabetic patients and patients newly diagnosed in general practice, respectively.

Conclusions: _targeted screening for type 2 diabetes (with a screening questionnaire as a first step) resulted in the identification of previously undiagnosed diabetic patients with a considerable prevalence of microvascular complications.