Letter to the Editor

Microvascular Disease and Cardiomyopathy

To describe the prevalence and risk factors of diabetic retinopathy in Asian Malays.

Population-based cross-sectional study.

Persons with diabetes of Malay ethnicity aged 40 to 80 years in Singapore.

Diabetes mellitus was defined as random glucose of 11.1 mmol/l or more, use of diabetic medication, or a physician diagnosis of diabetes. Retinal photographs taken from both eyes were graded for diabetic retinopathy using the modified Airlie House classification system.

Any diabetic retinopathy, retinopathy grades, macular edema, or vision-threatening retinopathy.

Of the 3261 persons who participated in this study, 757 (23.1%) had diabetes and gradable retinal photographs. In persons with diabetes, the overall prevalence of any retinopathy was 35.0% (95% confidence interval [CI], 28.2–43.4), the overall prevalence of macular edema was 5.7% (95% CI, 3.2–9.9), and the overall prevalence of vision-threatening retinopathy was 9.0% (95% CI, 5.8–13.8). Compared with men, women had significantly higher proportions with more severe diabetic retinopathy, moderate (12% vs. 4%) and severe (3% vs. 0.2%) nonproliferative retinopathy, proliferative retinopathy (7% vs. 2%), and vision-threatening retinopathy (13% vs. 3%). In multiple logistic regression, independent risk factors for any retinopathy were longer diabetes duration (odds ratio [OR], 1.07; 95% CI, 1.04–1.09, per year increase), higher hemoglobin A1_c (OR, 1.21; 95% CI, 1.10–1.33, per % increase), hypertension (OR, 1.85; 95% CI, 1.04–3.30), and higher pulse pressure (OR, 1.34, 95% CI, 1.19–1.51, per 10-mmHg increase); older age (OR, 0.73; 95% CI, 0.57–0.93, per decade increase) and higher total cholesterol levels (OR, 0.75; 95% CI, 0.63–0.89, per 1-mmol/l increase) were protective of any retinopathy. Vision-threatening retinopathy additionally was associated with previous stroke (OR, 3.74; 95% CI, 1.24–11.26), cardiovascular disease (OR, 2.23; 95% CI, 1.08–4.62), and chronic kidney disease (OR, 4.45; 95% CI, 2.18–9.07). Female gender was not an independent risk factor for diabetic retinopathy after adjusting for metabolic and socioeconomic risk factors.

One in 10 Malay adults with diabetes in Singapore has vision-threatening diabetic retinopathy. Risk factors for retinopathy in this population are largely similar to white populations elsewhere, suggesting that control of these risk factors may reduce both the prevalence and impact of retinopathy.

The authors have no proprietary or commercial interest in any materials discussed in this article.

The purpose of this study was to examine the association of diabetic retinopathy with incident heart failure (HF).

Microvascular disease might play a more prominent role in the pathogenesis of diabetic cardiomyopathy, a major cause of HF in diabetes. Whether diabetic retinopathy, a microvascular complication of diabetes, predicts HF is unclear.

A population-based study included 1,021 middle-aged type 2 diabetic persons with normal renal function and free of clinical coronary heart disease or HF at baseline. Diabetic retinopathy signs were graded from retinal photographs. Incident HF events were prospectively identified from hospital stay and death records.

There were 125 (12.8%) participants with diabetic retinopathy. After 9-year follow-up, 106 (10.1%) participants developed incident HF events. Persons with retinopathy were more likely to develop HF (cumulative incidence of 21.6%) than those without retinopathy (cumulative incidence of 8.5%). After controlling for age, gender, race, smoking, diabetes duration, insulin use, blood pressure, lipid profile, and other risk factors, participants with retinopathy had more than 2.5-fold higher risk of developing HF than those without retinopathy (hazard ratio [HR] 2.71; 95% confidence interval [CI] 1.46 to 5.05). This association remained significant after further adjustments for glycemic control, carotid atherosclerosis, and serum markers of endothelial dysfunction (HR 2.20, 95% CI 1.08 to 4.47).

The presence of diabetic retinopathy signifies an excess risk of HF, independent of known risk factors. This further supports a contribution of microvascular disease to the development of HF in people with diabetes.