The prevalence of diabetic retinopathy in patients with screen-detected type 2 diabetes in Denmark: the ADDITION study

The prevalence of type 2 diabetes is increasing, but the exact prevalence of the disease and its accompanying late complications are unknown. In the Anglo-Danish-Dutch study of Intensive Treatment in People with Screen-detected Diabetes in Primary Care (ADDITION study), patients with hitherto undiagnosed type 2 diabetes are identified using a stepwise screening strategy in selected general practices. This article reports the occurrence of diabetic retinopathy in this population. In angstrom rhus and Copenhagen counties, a total of 12 708 of the persons invited by mail were screened for diabetes mellitus. Consequently, 763 persons with type 2 diabetes were identified; 670 of these (335 from each of the two centres) underwent a general physical examination (including measurement of blood pressure and HbA1c) and an ophthalmological examination (including measurement of visual acuity and fundus photography). Retinopathy was graded from the photographs by counting all retinopathy lesions. Forty-five (6.8%) of the examined patients had any retinopathy, of which the majority was minimal. No patients had severe non-proliferative or proliferative diabetic retinopathy. There was no significant difference between age, sex and visual acuity among patients with and without retinopathy. However, the patients with retinopathy had significantly higher HbA1c and systolic and diastolic blood pressure than the patients without retinopathy. Patients with screen-detected diabetes have a low prevalence of diabetic retinopathy and no vision-threatening lesions. Screening for diabetic retinopathy should be focused on those patients who have already been diagnosed with type 2 diabetes during routine clinical practice.