Retinopathy predicts mortality from CHD
The presence of retinopathy increases the risk of coronary-related death. This increased risk appears to be equivalent to the presence of diabetes alone.
Retinopathy lesions such as microaneurysms, haemorrhages, cottonwool spots and hard exudates are a well recognised complication of diabetes. However, these lesions, in particular microaneurysms and haemorrhages, can also be found in older people without diabetes or impaired glucose metabolism. Their presence may independently predict cardiovascular risk with retinopathy acting as a marker for subclinical vascular disease.
A prospective population-based cohort study from Australia addressed the association between retinopathy and coronary risk in people aged over 49 years. The study included 199 people with diabetes and 2,768 without.
The presence and severity of retinopathy was assessed by retinal photography and the 12-year cumulative CHD mortality determined from national death index records.
The results were adjusted for other cardiovascular risk factors such as age, gender, smoking and hypertension. A total of 353 people (11.9%) had CHD-related deaths at 12 years. Retinopathy was present in 57 of the diabetes group (29%) and 268 of the group without diabetes (10%).
Retinopathy was shown to be an independent predictor of CHD mortality regardless of the presence of diabetes (HR 2.21, 95% CI 1.20 - 4.05 in the diabetes group and HR 1.33, 95% CI 1.02 - 1.83 in the non-diabetes group). There were no significant differences between men and women.
The more severe the retinopathy the greater the risk with the presence of moderate retinopathy increasing the hazard ratio to HR 6.68, 95% CI 2.24 - 20.0 in the diabetes group and HR 2.29, 95% CI 1.10 - 4.76 in the other group.
The most striking fact in this study is that retinopathy not only increases the risk of coronary-related death but this increased risk is equivalent to the presence of diabetes alone.
This study used retinal photography and direct ophthalmoscopy is certainly less accurate and more likely to miss milder disease.
However, by the same token the retinopathy detected in the GP's surgery will be more likely to be severe and therefore confer greater risk. So it may be time to add the ophthalmoscope to CVD risk assessment.
Liew IG, Wong TY, Mitchell P et al. Retinopathy predicts coronary heart disease mortality. Heart 2009;95:391-394Reviewer
Dr Peter Savill
GPwSI cardiology, Southampton