High prevalence of advanced retinopathy in patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study

https://doi.org/10.1016/j.diabres.2012.09.006Get rights and content

Abstract

Aims

The natural history of diabetic complications, including diabetic retinopathy (DR), is changing due to improved care. This study aimed at assessing prevalence of advanced DR and its correlation with risk factors and complications in subjects with type 2 diabetes from the Renal Insufficiency and Cardiovascular Events (RIACE) Italian Multicenter Study.

Methods

This study enrolled 15,773 patients visiting consecutively 19 Diabetes Clinics in years 2007–2008. DR was assessed by dilated fundoscopy and classified according to the Global Diabetic Retinopathy Project Group.

Results

Advanced DR was observed in 9.8% of patients (4.2% pre-proliferative, 4.2% proliferative, 1.3% maculopathy, 0.1% blindness). Advanced DR was independently associated with hemoglobin (Hb) A1c, diabetes duration and treatment, particularly with insulin, hypertension, previous cardiovascular disease (CVD), albuminuria and, inversely, age, age at diabetes diagnosis, smoking and estimated glomerular filtration rate. Maculopathy alone was associated with female gender, but not HbA1c, hypertension and age.

Conclusions

We found an alarming high prevalence of advanced DR in subjects with type 2 diabetes from the RIACE cohort, suggesting that the expected favorable effect of improved diabetes management has not emerged yet. Independent correlates of advanced DR were indexes of glycemic exposure, hypertension, CVD, albuminuria and, inversely, age at diagnosis and smoking.

Introduction

Diabetic retinopathy (DR) is a common and highly specific microvascular complication of diabetes mellitus and represents the leading cause of blindness among working-age individuals in developed countries [1]. DR occurs both in type 1 and type 2 diabetes and is strictly related to the duration of the disease: virtually all individuals diagnosed with diabetes at less than 30 years of age [2] and more than 70% of individuals diagnosed aged 30 years or older [3] develop DR after 15 years of diabetes duration. However, there are substantial differences between type 1 and type 2 diabetes in terms of clinical presentation, prevalence, and, at least in part, risk factors of DR.

Proliferative DR (PDR) is the most common sight-threatening lesion in type 1 diabetes [4], whereas diabetic macular edema (DME) is the primary cause of loss of visual acuity [5] and usually precedes PDR [6] in type 2 diabetes. Prevalence of any DR is higher in type 1 than in type 2 diabetes and also in males than in females, as recently shown in a Swedish cohort [7]. However, prevalence estimates are quite variable across the world [8] and it is unclear whether recent improvements in diabetes care have resulted in significant reduction of this complication and particularly of its sight-threatening lesions. Re-analysis of individuals under poor control in 25 years of follow-up revealed only minor improvements following implementation of improved care [9], even though an intensive glucose control early in the course of the disease produced significant and persistent benefits on microvascular complications including DR, both in type 1 [10] and in type 2 [11] diabetes. In addition to the extent and duration of chronic hyperglycemia [12], [13], other risk factors for DR are hypertension [13], [14] and dyslipidemia [15]; conversely, the role of age, gender and smoking is controversial and seems to differ between type 1 and type 2 diabetes [16], [17].

This study was aimed at assessing real-life prevalence and correlates of advanced DR, including severe non-PDR, PDR and maculopathy, in the large cohort of Caucasian patients with type 2 diabetes from the Renal Insufficiency and Cardiovascular Events (RIACE) Italian Multicenter Study.

Section snippets

Design

The RIACE Italian Multicenter Study is an observational, prospective cohort study on the impact of estimated GFR (eGFR) on morbidity and mortality from cardiovascular disease (CVD) in subjects with type 2 diabetes. The study protocol was approved by the locally appointed ethics committees. Here, we report a cross-sectional analysis of DR data collected at the baseline visit.

Patients

The RIACE cohort consisted of 15,933 Caucasian patients with type 2 diabetes (defined by the American Diabetes Association

Results

No signs of DR were detected in the vast majority of patients from the RIACE cohort (78.2%), though a high percentage of individuals with any DR showed advanced lesions (Table 1).

Subjects with advanced or non-advanced DR were slightly older, more frequently male (not significantly) and non-smokers, had lower age at diabetes onset, much longer diabetes duration, higher HbA1c, systolic BP, albuminuria, and serum creatinine (only those with advanced DR), and lower total and LDL-cholesterol,

Discussion

This study from a large Italian cohort shows that advanced DR (a) is present in almost 10% of contemporary subjects with type 2 diabetes, despite a relatively low prevalence of any DR (22.2%); and (b) correlates with indexes of glycemic exposure (i.e. HbA1c, diabetes duration and treatment, especially with insulin), hypertension, CVD, albuminuria, and, inversely with age, age at diabetes diagnosis, smoking and eGFR.

A prevalence of any DR of 22.2% is lower than that reported for Caucasian

Grant support

This work was supported by the Research Foundation of the Italian Society of Diabetology (Fo.Ri.SID) and the Diabetes, Endocrinology and Metabolism (DEM) Foundation, and by unconditional grants from Eli-Lilly, Takeda, Chiesi Farmaceutici and Boehringer-Ingelheim.

Meeting presentation

Data from the manuscript have been presented at the 72nd Annual Meeting of the American Diabetes Association, June 8–12, 2012, Philadelphia, PA.

Conflict of interest statement

None.

Acknowledgment

The authors thank the RIACE Investigators for participating in this study (see the complete list as on-line Appendix).

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    Registration number: NCT00715481.

    1

    A complete list of the RIACE Investigators can be found as on-line appendix.

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