Prevalence and 25 year incidence of proliferative retinopathy among Danish type 1 diabetic patients.
OBJECTIVE
This study aimed to evaluate the prevalence of retinopathy in long-surviving type 1 diabetic patients. It also investigated the 25 year incidence of proliferative retinopathy and associated risk factors in a Danish population-based cohort.


METHODS
A population-based cohort of 727 type 1 diabetic patients from Fyn County, Denmark, was identified in 1973. In 1981-1982, baseline retinopathy was graded and other risk factors were assessed in 573 patients. Twenty-five years later, 308 patients were still alive. Of these, 201 (65.3%) were re-examined at follow-up in 2007-2008.


RESULTS
The median age and duration of diabetes at follow-up were 58.8 and 43 years, respectively. At follow-up, the prevalence of diabetic retinopathy was 97.0%. Non-proliferative retinopathy was found in 45.8%, and 51.2% had proliferative retinopathy. The 25 year incidence of proliferative retinopathy was 42.9% among patients at risk. In a multivariate analysis, baseline HbA(1) (OR 2.14 per 1% increase, 95% CI 1.06-4.31) and non-proliferative retinopathy (OR 4.61, 95% CI 1.94-11.0) were the only risk factors for incident proliferative retinopathy. The long-term incidence of proliferative retinopathy was not associated with baseline duration of diabetes, proteinuria, smoking, body mass index, maculopathy or systolic or diastolic blood pressure.


CONCLUSIONS
Retinopathy among long-surviving type 1 diabetic patients is almost universal. Proliferative retinopathy was found in half of these patients. In addition, the 25 year incidence of proliferative retinopathy was high. Baseline glycaemic regulation and non-proliferative retinopathy were identified as risk factors for incident proliferative retinopathy.
Grauslund
J
J
Department of Ophthalmology, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark. jakob.grauslund@ouh.regionsyddanmark.dk
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D000328:Adult; D017668:Age of Onset; D015331:Cohort Studies; D003718:Denmark; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D013997:Time Factors
D006442:Glycated Hemoglobin