Prevalence of Diabetic Retinopathy among Subjects with Known Diabetes in China: The Beijing Eye Study

Prevalence of diabetic retinopathy in various ethnic groups: a worldwide perspective

The alarming rise in diabetes prevalence is a global public health and economic problem. Diabetic retinopathy is the most common complication of diabetes and the leading cause of blindness among working-age populations in the Western world. Screening and prompt treatment of diabetic retinopathy are not top priorities in many regions of the world, because the impacts of other causes of preventable blindness remain an issue. Ethnicity is a complex, independent risk factor for diabetic retinopathy. Observations from white populations cannot be extrapolated fully to other ethnic groups. The prevalence of diabetic retinopathy, sight-threatening diabetic retinopathy, and clinically significant macular edema are higher in people of South Asian, African, Latin American, and indigenous tribal descent compared to the white population. Although all ethnic groups are susceptible to the established risk factors of diabetic retinopathy-such as length of exposure and severity of hyperglycemia, hypertension, and hyperlipidemia-ethnic-specific risk factors also may influence these rates. Such risk factors may include differential susceptibility to conventional risk factors, insulin resistance, differences in anthropometric measurements, truncal obesity, urbanization, variations in access to healthcare systems, genetic susceptibility, and epigenetics. The rates of nonproliferative diabetic retinopathy appear to be declining in the United States, supporting the observation that better medical management of diabetes and prompt treatment of sight-threatening diabetic retinopathy substantially improve the long-term diabetic retinopathy incidence; studies from other parts of the world are limited and do not mirror this finding, however. We examine the ethnicity and region-based prevalence of diabetic retinopathy around the world and highlight the need to reinforce ethnicity-based screening and treatment thresholds in diabetic retinopathy.

Determination of diabetic retinopathy prevalence and associated risk factors in Chinese diabetic and pre-diabetic subjects: Shanghai diabetic complications study

BACKGROUND

The prevalence of diabetic retinopathy is not well studied in the Chinese pre-diabetic population, also known as impaired glucose regulation. Hence, we investigated the prevalence of and risk factors associated with retinopathy in diabetic and pre-diabetic subjects from Chinese communities.

METHODS

A total of 3736 Chinese subjects were recruited from urban communities in Shanghai. The participants were classified as normal glucose tolerance, impaired glucose regulation (IGR) and diabetes based on the 75 g oral glucose tolerance test. The levels of diabetic retinopathy (DR) were assessed with non-mydriatic retinal photographs according to the Diabetic Retinopathy Disease Severity Scale.

RESULTS

The prevalence of diabetic retinopathy in patients with diabetes and impaired glucose regulation subjects was 9.4% and 2.5%, respectively. In subjects with IGR, hypertension (odds ratio: 3.54, p = 0.028), including elevated systolic and diastolic blood pressure and obesity (odds ratio: 3.53, p = 0.028) were significantly associated with diabetic retinopathy after age and sex adjustments. The factors associated with retinopathy in diabetes included diabetes duration, blood glucose levels, glycated hemoglobin levels, and the presence of albuminuria. Diabetic retinopathy was significantly associated with fasting plasma glucose in known diabetes, whereas in newly-diagnosed subjects, diabetic neuropathy was closely correlated to postprandial plasma glucose.

CONCLUSIONS

Hyperglycemia was a strong risk factor for diabetic retinopathy. In pre-diabetic subjects, diabetic retinopathy was also associated with hypertension and obesity.

Prevalence of diabetic retinopathy in patients with recently diagnosed diabetes mellitus

BACKGROUND

The severity of diabetic retinopathy is well known to have a close association with the duration of diabetes mellitus. Patients with recently diagnosed diabetes should have adequate eye examinations to eliminate the possibility of diabetic retinopathy being present because there is no accurate means of determining the duration of the disease. The prevalence of diabetic retinopathy in type 2 diabetic patients with known duration up to one year was investigated in the present study.

METHODS

A centre for diabetic retinopathy screening was set up in a community in Hong Kong. The screening procedures included history taking, visual acuity measurement, anterior ocular health assessment and retinal examination by fundus photography. Fundus photographs were taken in nine different positions of gaze through natural or dilated pupils. Using the criteria recommended by the American Optometric Association the retinopathy was graded in severity. 'Recently diagnosed diabetes mellitus' was defined as having diabetes diagnosed by a physician within the previous year.

RESULTS

A total of 12,112 patients having their first visits to the centre were recruited from 2006 to 2009. Among them, 3,510 patients had recently diagnosed diabetes. The mean age of patients was 59.5 years. The prevalence of diabetic retinopathy was 18.2 per cent (639 patients) among the recently diagnosed diabetic patients. Most of the patients had mild non-proliferative diabetic retinopathy. In these 639 patients, approximately seven per cent had sight-threatening retinopathy that included significant macular oedema, all of whom required monitoring. The presence of hypertension or smoking was not significantly associated with the prevalence of diabetic retinopathy in recently diagnosed diabetic patients.

CONCLUSIONS

Screening for diabetic retinopathy is important for newly diagnosed diabetic patients. In Hong Kong, the prevalence of diabetic retinopathy was alarmingly high and some patients had already developed sight-threatening retinopathy that included macular oedema. Most of them had no symptoms until the retinopathy progressed and they developed macular oedema. A systematic screening program in the community is needed for early detection and to reduce blindness in diabetic patients.

Cutaneous markers of coronary artery disease

Coronary artery disease (CAD) is rapidly increasing in prevalence across the world and particularly in south Asians at a relatively younger age. As atherosclerosis starts in early childhood, the process of risk evaluation must start quite early. The present review addresses the issue of cutaneous markers associated with atherosclerosis, and the strengths and weaknesses of the markers in identifying early coronary atherosclerosis. A diligent search for such clinical markers, namely xanthelasma, xanthoma, arcus juvenilis, acanthosis nigricans, skin tags, ear lobe crease, nicotine stains, premature graying in smokers, hyperpigmented hands in betel quid sellers, central obesity, and signs of peripheral vascular disease may prove to be a rewarding exercise in identifying asymptomatic CAD in high risk individuals.

A review of clinical trials of anti-VEGF agents for diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a leading cause of vision loss in the working-age population worldwide. Many observational and preclinical studies have implicated vascular endothelial growth factor (VEGF) in the pathogenesis of DR, and recent successes with anti-VEGF therapy for age-related macular degeneration (AMD) have prompted research into the application of anti-VEGF drugs to DR. Here we review the numerous early studies that suggest an important potential role for anti-VEGF agents in the management of diabetic retinopathy.

CONCLUSIONS

For diabetic macular edema, phase II trials of intravitreal pegaptanib and intravitreal ranibizumab have shown short-term benefit in visual acuity. Intravitreal bevacizumab also has been shown to have beneficial short-term effects on both visual acuity and retinal thickness. For proliferative diabetic retinopathy (PDR), early studies suggest that intravitreal bevacizumab temporarily decreases leakage from diabetic neovascular lesions, but this treatment may be associated with tractional retinal detachment (TRD). Furthermore, several studies indicate that bevacizumab is likely to prove a helpful adjunct to diabetic pars plana vitrectomy (PPV) for TRD. Finally, three small series suggest a potential beneficial effect of a single dose of bevacizumab to prevent worsening of DME after cataract surgery. Use of anti-VEGF medications for any of these indications is off-label. Despite promising early reports on the safety of these medications, we eagerly await the results of large, controlled trials to substantiate the safety and efficacy of anti-VEGF drugs for diabetic retinopathy.

Diagonal ear lobe crease in diabetic south Indian population: is it associated with Diabetic Retinopathy? Sankara Nethralaya Diabetic Retinopathy Epidemiology And Molecular-genetics Study (SN-DREAMS, Report no. 3)

BACKGROUND

To report the prevalence of ear lobe crease (ELC), a sign of coronary heart disease, in subjects (more than 40 years old) with diabetes and find its association with diabetic retinopathy.

METHODS

Subjects were recruited from the Sankara Nethralaya Diabetic Retinopathy Epidemiology And Molecular-genetics Study (SN-DREAMS), a cross-sectional study between 2003 and 2006; the data were analyzed for the 1414 eligible subjects with diabetes. All patients' fundi were photographed using 45 degrees four-field stereoscopic digital photography. The diagnosis of diabetic retinopathy was based on the modified Klein classification. The presence of ELC was evaluated on physical examination.

RESULTS

The prevalence of ELC, among the subjects with diabetes, was 59.7%. The ELC group were older, had longer duration of diabetes, had poor glycemic control and had a high socio-economic status compared to the group without ELC and the variables were statistically significant. There was no statistical difference in the prevalence of diabetic retinopathy in two groups. On multivariate analysis for any diabetic retinopathy, the adjusted OR for women was 0.69 (95% CI 0.51-0.93) (p = 0.014); for age >70 years, 0.49 (95% CI 0.26-0.89) (p = 0.024); for increasing duration of diabetes (per year increase), 1.11(95% CI 1.09-1.14) (p < 0.0001); and for poor glycemic control (per unit increase in glycosylated haemoglobin), 1.26 (95% CI 1.19-1.35) (p < 0.0001). For sight-threatening diabetic retinopathy, no variable was significant on multivariable analysis. In predicting any diabetic retinopathy, the presence of ELC had sensitivity of 60.4%, and specificity, 40.5%. The area under the ROC curve was 0.50 (95% CI 0.46-0.54) (p 0.02).

CONCLUSION

The ELC was observed in nearly 60% of the urban south Indian population. However, the present study does not support the use of ELC as a screening tool for both any diabetic retinopathy and sight-threatening retinopathy.