Eye News: Many Cases of Diabetic Retinopathy are being Missed in the U.S.

Underuse of the Health Care System by Persons With Diabetes Mellitus and Diabetic Macular Edema in the United States

From JAMA Ophthalmol. Published online December 19, 2013. doi:10.1001/jamaophthalmol.2013.6426

The above heading is the title of the study that was published in JAMA Ophthalmology regarding the awareness of diabetic eye problems and usage of the health care system by diabetics in the United States.  However, I have some different conclusions about the results of this study which I will discuss below.

Diabetic retinopathy is most most common cause of vision loss in working age adults in the United States, and most cases of vision loss come from diabetic macular edema, or swelling in the most visually sensitive part of the eye.  This study looked at a sample of people participating in the National Health and Nutrition Examination Survey (NHANES).  This survey is a series of cross-sectional surveys conducted by the National Center for Health Statistics, a part of the Centers for Disease Control and Prevention.  Participants were selected from the non-institutionalized civilian population in the United States by using a stratified, multistage, probability sampling design. This study analyzed data from the 2005 to 2008 NHANES cycles, when retinal photographs were obtained among participants 40 years or older.  In this survey, 798 people were self-reported as being diabetic, out of 6707 people in the survey overall.

Of the 798 people self-reported as diabetic, a series of questions was asked, the retinal photographs were reviewed in a photograph reading center for evidence of diabetic retinopathy and macular edema, and their recorded visual acuity was noted.  The questions that were asked were:

1. “Have you been told by a doctor that diabetes has affected your eyes or that you had retinopathy?” (Yes or No)
2. “When was the last time you saw a diabetes nurse educator or dietitian or nutritionist for your diabetes?” (Less than 1 year or more than 1 year / never)
3. “When was the last time you had an eye examination in which the pupils were dilated?” (Less than 1 year or more than 1 year / never)

The answers were compared to the actual presence of retinopathy based on the analysis of the photographs and also to their visual acuity.

Study Results:

• Among 798 persons with self-reported diabetes mellitus in the analytic sample, 238 had diabetic retinopathy without diabetic macular edema and 48 had diabetic macular edema.
• It was noted that the people with diabetic macular edema had higher hemoglobin A1c levels and a longer duration of diabetes.
• Among those with diabetes mellitus and diabetic macular edema, only 45% reported being told by a physician that diabetes mellitus had affected their eyes or that they had retinopathy.
• Only 26% with diabetic retinopathy but no macular edema reported being told by a physician that diabetes mellitus had affected their eyes or that they had retinopathy.
• Only 49% with diabetes and macular edema reported seeing a diabetes nurse educator, a dietician, or a nutritionist for their diabetes mellitus within the past year compared with 34%  with diabetic retinopathy but no macular edema and 31% with diabetes mellitus but no retinopathy.
• 46.7% with diabetic macular edema reported seeing a diabetes specialist more than 1 year ago or never, and 65% with diabetic retinopathy but no macular edema and 70% with diabetes mellitus but no retinopathy reported seeing a diabetes specialist more than 1 year ago or never.
• Only 60% of persons with diabetic macular edema reported having had an eye examination within the past year at which the pupils were dilated.  68% with diabetic retinopathy but no macular edema and 62% with diabetes mellitus but no retinopathy reported having had an eye examination within the past year at which the pupils were dilated.

These numbers are alarming for a number of reasons:

• 30% to 40% of diabetics had not had an eye examination in over a year, many of which had diabetic retinopathy and vision threatening macular edema.
• Less than half of diabetics with diabetic retinopathy and macular edema reported being told that they had diabetic retinopathy by their eye physician.
• The majority of patients with diabetic retinopathy had not seen a diabetes specialist in over a year.

From these results, it can be determined that there is an under-utilization of health care services by diabetics.  This includes a large number of diabetics not getting their recommended annual eye examinations as well as not seeing diabetes specialists, nurse educators, and dieticians.  However, I believer that there may also be a problem with the eye examinations that these patients are receiving:

• There is a possibility that diabetic retinopathy is not being diagnosed at the time of the eye examination.  Are these patients being seen by an eye care provider "experienced in the diagnosis and treatment of diabetic retinopathy", as recommended by the American Academy of Ophthalmology?  Is it possible that these patients are getting cursory, undilated examinations without retinal photography with cases of significant retinopathy being missed?
• There is also a possibility that there is a lack of communication between the eye care provider and the patient, or a lack of understanding on the patient's part.

Both of these possibilities could lead to the low number of patients reporting that they were told they had retinopathy compared to the findings of the retinal photographs that were taken.

The main recommendations at this point regarding diabetic eye care would be:

• Be sure to have an annual dilated eye examination specifically looking for complications of diabetes.
• Be sure that the examination is by an ophthalmologist experienced in diagnosing diabetic retinopathy.
• Be clear that you know at the end of the examination whether or not you have diabetic retinopathy, how severe it is, is it vision threatening, and does it need to be treated.
• The eye care provider should communicate his findings back to the doctor treating the diabetes medically.