Diabetic Retinopathy and Mortality

It has consistently been demonstrated that patients with diabetes have a higher mortality, which is mainly caused by cardiovascular and cerebrovascular diseases. There is a close correlation between micro- and macrovascular disease in diabetes. Given that diabetic retinopathy (DR) is the most common microvasculopathy and that it is easily accessible for non-invasive evaluation, it has been proposed as a suitable biomarker for mortality. The impact of DR on all-cause mortality has been evaluated in 15 studies including more than 20,000 patients. In general some associations were demonstrated in type 1 diabetes, but these were mainly explained by confounding factors like age, sex, duration of disease, glycaemic dysregulation, hypertension and nephropathy. Interestingly, stronger correlations between DR and mortality have been demonstrated in type 2 diabetes, and these are likely to be less effected by systemic confounders. In both types of diabetes, there is a tendency towards a higher risk of mortality in patients with increasing levels of DR. In particular, patients with proliferative DR have a higher risk, which may be explained by shared pathophysiological pathways in the retinal and systemic microvasculature causing a higher risk of early death in patients with the most severe types of DR.