Ten-year incidence of diabetic retinopathy and macular edema. Risk factors in a sample of people with type 1 diabetes
Introduction
Diabetes mellitus (DM) is defined as a group of metabolic diseases whose common feature is an elevated blood glucose level (hyperglycaemia). Diabetes mellitus is a major health problem worldwide. In 2010 more than 200 million patients had diabetes. The world's population is predicted to increase by 62% between the years 1995 and 2025, and the prevalence of DM by over 120% [1].
In 2000, the World Health Organization Expert Committee on Diabetes [2] defined diabetes as >7.0 mmol/L (126 mg/dl) and as >11.1 mmol/L (200 mg/dl) 2 h after a 75 g glucose load.
Diabetic retinopathy (DR) is the most important cause of blindness in type 1 DM (DM1) patients [3]. Several factors appear to influence susceptibility to DR; the most powerful risk factors for DR are the duration of diabetes, high glycemic levels and arterial hypertension [4].
The importance of lipids in the development of DR has been studied but with differing results, many studies not finding any association, and others observing some relationship between lipids and different diabetic retinopathy complications such as diabetic macular edema (DME) or the number of lipid exudates in the eye fundus [5].
The aim of the present study is to determine the ten-year incidence of diabetic retinopathy in a population-based study of registered DM1 patients in our Health Care Area (HCA) and its risk factors, with lipids as independent risk factors being the focus of interest.
Section snippets
Setting
Hospital St Joan is the only public ophthalmology centre in Reus (Catalonia, Spain), and has a dependent population of 322,740. All type DM1 patients referred by general practitioners and endocrinologists since 1990 (1059) have been registered at the Ophthalmology Service. Since 1987, there has been a steady increase of 11.4 new cases per 100,000 inhabitants (13.2 men and 9.6 women).
Design
The present study is a population-based prospective ten-year study of a sample of all DM1 patients referred in
Demographic variables of the patients (Table 1)
Baseline patients’ characteristics can be seen in Table 1, thus: gender: 53.00% were men and 47.00% women; current age: between 19 and 59 years with a mean of 26.17 ± 11.74 years; diabetes duration: 7.88 ± 5.47 years (1–35 years); Microalbuminuria present in 3.59% of patients, and arterial hypertension in 30.50%; mean HbA1c, 7.72 ± 1.42%.
Incidence of diabetic retinopathy and macular edema (Table 2)
The ten-year incidence of any diabetic retinopathy was 120 patients (35.90%), and diabetic macular edema was observed in 37 patients (11.07%) of these 120 patients.
Discussion
The present study includes 334 from a total of 1059 DM1 patients surveyed in our area (of 322,740 inhabitants). Since all DM1 patients have been counted in our hospital since 1990, we believe that the results are highly representative and may be extended to other DM1 patients in our area.
The incidence of DR and DME in the present study at the ten-year follow up of a DM1 patient sample is similar to other studies carried out with patients submitted to conventional insulin treatments like the
Contributors
P.R-A. has contributed to the study design, researched data analysis, discussion, manuscript writing and supervision of the manuscript. M.B-B. has contributed to the ophthalmologic data collection, discussion, review and edition of the manuscript. N.P-G. has contributed to the study design, systemic disease diagnosis and laboratory analysis interpretation, researched data analysis and discussion. I.M-M. has contributed to the ophthalmologic data collection and research. J.F-B. has contributed
Conflict of interest
The authors state that they have no conflict of interest relevant to this article to disclose.
Acknowledgments
Medical School, University Rovira I Virgili of Tarragona, (Spain) for the technical assistance. Institut de Investigacio Sanitaria Pere Virgili (IISPV): for its analysis data support and providing funds.
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