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American Diabetes Association Updates on Diabetic Retinopathy

Improvements in assessment and treatment of diabetic retinopathy position statement

Diabetic retinopathy (DR) is a complication of diabetes that affects vision. High blood sugar levels can damage the blood vessels starving the retina of vital nutrients and oxygen resulting in blurry vision. Without appropriate treatment this condition may lead to complete vision loss. A recent update on diabetic retinopathy by American Diabetes Association (ADA) has considerably improved in terms of diagnosing and treating this complication since the 2002 ‘Position Statement.’

The statement was comprised of natural history of diabetic retinopathy with associated risk factors and different stages categorized by the growth of new blood vessels on the retina and posterior surface of the vitreous. The four stages ranged from mild non-proliferative diabetic retinopathy (NPDR) to moderate NPDR, to severe NPDR, to the most advanced stage – proliferative diabetic retinopathy (PDR). It evaluated the general acceptance of optical coherence tomography to assess retinal thickness, along with intraretinal pathology and wide-angle fundus photography to expose clinically silent microvascular lesions. Moreover, it summarized the recent data on screening and treatment with recommendations and discussed about cost-effectiveness.

DR is explicitly a neurovascular complication of both type 1 and type 2 diabetes and its rate of occurrence depends on the level of glycemic control and the duration of diabetes. Other risk factors associated with DR include hyperglycemia, nephropathy, hypertension, and dyslipidemia. Studies have proven that reduction in blood pressure (BP) decreases the progression of retinopathy in people with type 2 diabetes, but strict BP targets (systolic blood pressure of 120 mmHg vs. 140 mmHg) do not provide additional benefits. In another study, retinopathy progression was slowed in patients with dyslipidemia by adding fenofibrate, mainly in NPDR at baseline. In addition, several studies propose that pregnant patients with type 1 diabetes may exacerbate retinopathy with poor glycemic control during conception and may threaten their vision.

Optimization of blood glucose, blood pressure, and serum lipid levels in conjunction with appropriately scheduled dilated eye examinations can decrease the risk of vision loss from DR complications, but a substantial amount of those affected with diabetes develop diabetic macular edema (DME) or proliferative changes that require intervention. Large prospective randomized studies have shown that the use of intensive therapy could possibly prevent or delay DR with the goal of attaining near-normoglycemia. Although, intravitreal injection of anti–vascular endothelial growth factor agents may treat DME and PDR, it may threaten reading vision.

A meta-analysis study, conducted worldwide from 1980–2008 and consisting of 35 studies, predicted the global prevalence of DR to be 35.4% and PDR to be 7.5%. In developed countries, DR is mostly the cause of new cases of blindness among those 20 to 74 year old and eye disorders, such as glaucoma and cataracts, are frequently seen in diabetes patients. However, recent advancements in systemic therapy of diabetes have helped patients to improve their metabolic control. The statement incorporates these medical developments for the use of physicians and patients to aid in diagnosis and treatment of DR. It also provides an opportunity to improve glucose management and avoid or delay potential progression of the retinopathy.

The statement includes that screening recommendations for patients with diabetes depend on the rates of appearance and progression of DR and the associated risk factors. Ophthalmologist or optometrist examinations in patients with type 1 and 2 diabetes should be within 5 years after onset of diabetes and at the time of diabetes diagnosis, respectively. Women planning for pregnancy or who are pregnant with pre-existing diabetes should be examined before pregnancy or in the first trimester. In diabetes patients where no evidence of retinopathy is found, follow-up eye exams can be scheduled every two years. If any retinopathy is identified, then subsequent dilated-pupil retina exams are advised at least yearly, but more frequently if progressive retinopathy is diagnosed.

Fortunately, the cost-effectiveness of screening and traditional laser treatment for DR has been established with no more disputes. It is focused on telemedicine’s impact on the detection and eventual management of DR that appears to be most effective with lower ratio of providers to patients, with prohibitive distance to reach a provider, or when the alternative is no patient screening. The latest advancement in retinopathy treatment, anti-VEGF therapy has been taken into consideration, as they are more cost-effective than laser monotherapy for DME. Also, having retinopathy is not contraindicated with aspirin therapy for cardioprotection because studies suggest that aspirin does not increase the risk for retinal hemorrhage. Nonetheless, future studies are needed to determine the cost-effectiveness of anti-VEGF as a first-line treatment option for PDR.

Practice Pearls:

  • Optimize glycemic control, blood pressure, and serum lipids to reduce the risk or slow the progression of diabetic retinopathy.
  • Follow the screening recommendations for patients with diabetes for eye examination by ophthalmologist or optometrist.
  • The presence of retinopathy is not a contraindication to aspirin therapy for cardioprotection because aspirin does not increase the risk of retinal hemorrhage.

Reference:

Javitt JC, Canner JK, Sommer A. Cost effectiveness of current approaches to the control of retinopathy in type I diabetics. Ophthalmology 1989;96:255–264 42

Pasquel FJ, Hendrick AM, Ryan M, Cason E, Ali MK, Narayan KMV. Cost-effectiveness of different diabetic retinopathy screening modalities. J Diabetes Sci Technol 2015;10:301–307

Solomon SD, Chew E, Duh EJ, Sobrin L, Sun JK, VanderBeek BL, Wykoff CC, and Gardner TW. Diabetic Retinopathy: A Position Statement by the American Diabetes Association. Diabetes Care. Mar 2017; 40(3): 412-418.https://doi.org/10.2337/dc16-2641