This activity for Diabetic Retinopathy education is provided by Med Learning Group.
This activity is supported by an independent medical education grant from Regeneron Pharmaceuticals, Inc.
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Consequences of DR
Symptoms of diabetic retinopathy (DR) may include:1,2
Risk factors for development of DR
The duration of the diabetes and magnitude of elevation of blood sugar are the largest risk factors for development of DR.7-10 There is an exponential relationship between the risk of DR and mean hemoglobin A1c level (HbA1c).11 Therefore, it is recommended that HbA1c be 7% or lower for most patients.12 The most important modifiable risk factors for development of DR include blood sugar and blood pressure.13 Poor blood sugar control during pregnancy increases the risk of DR in patients with pre-existing diabetes.14
Risk Factors for progression of DR
The largest risk factor for progression of DR is poor blood sugar control.15,16 For every 10% reduction in HbA1c, there is a 39% risk reduction of retinopathy progression.17 Caution should be exercised regarding the aggressiveness of glucose control, as rapid improvement of longstanding hyperglycemia increases the risk of progression of DR in some patients. With this in mind, more frequent visits to an eye care provider are advised during this period.18
Treatment for other systemic comorbidities may also impact DR progression. Lipid lowering medications have been shown to slow the progression of DR, although the mechanism by which these agents slow the progression of DR is currently under investigation.19 Puberty, as well as pregnancy can also cause progression of DR; while changes in physiology and metabolic control are responsible in pregnancy, puberty is less clearly delineated, although hormonal changes seem to exert an effect independent of age and duration of disease.11,20
Systemic disease and DR
Damage to retinal blood vessels is part of systemic microvascular dysfunction in diabetes.21,22 Evidence of microvascular dysfunction such as diabetic nephropathy and neuropathy increases the risk of developing DR. In fact, patients with diabetic neuropathy are at 5-fold increased risk of nonproliferative diabetic retinopathy (NPDR) and 3-fold increased risk of proliferative diabetic retinopathy (PDR).23,24 In addition to the increased risk of developing DR, patients with diabetic neuropathy are also at increased risk of progression of DR.25 Regardless of the presence of systemic comorbidities, development of PDR correlates with increased risk of nephropathy, myocardial infarction, and stroke.11