Aug. 10, 2010 -- Diabetes has increased in the United States and so, too, has the prevalence of diabetic retinopathy, according to a new CDC study.
CDC researchers estimate that 28.5% of U.S. diabetes patients over age 40 have diabetic retinopathy, an eye disorder in which the blood vessels of the retina are damaged by diabetes. CDC researchers also reported that 4.4% of the U.S. population is estimated to have vision-threatening retinopathy, which, if left untreated, can lead to blindness.
The findings suggest a need for more comprehensive eye care, particularly among patients with diabetes who are at risk for retinopathy, the researchers report. Their study results are published in the Aug. 11 issue of the Journal of the American Medical Association.
Eight percent of the U.S. population is estimated to have diabetes, but CDC researchers note there have been few studies documenting the prevalence of diabetic retinopathy. “Investigating the prevalence of diabetic retinopathy is important because it is a key indicator of systemic diabetic microvascular complications, and as such, a sentinel indicator of the impact of diabetes,” writes the research team led by Xinzhi Zhang MD, PhD.According to the authors, diabetic retinopathy is the leading cause of new cases of legal blindness in the U.S. among people aged 20 to 74, and treating diabetes-related blindness costs about $500 million per year.
Researchers analyzed data on 1,006 people who participated in the National Health and Nutrition Examination Survey 2005-2008. Participants with gestational diabetes, severe visual impairment, or eye infections were excluded from the analysis.
The study, based on data of more than 1,000 diabetes patients, found:
There were gender differences: 31.6% men and 25.7% of women over age 40 who have diabetes are estimated to have diabetic retinopathy.
There were also racial/ethnic differences: 38.8% of non-Hispanic blacks were estimated to have diabetic retinopathy, 34% of Mexican-Americans, and 26.4% of non-Hispanic whites. These differences were also true for more advanced diabetic retinopathy; 9.3% of non-Hispanic blacks were estimated to have vision-threatening diabetic retinopathy, 7.3% of Mexican-Americans, and 3.2% of non-Hispanic whites.
Interestingly, age was not a major factor among the study group; 4.1% of people aged 40 to 64 were estimated to have diabetic retinopathy, compared with 5.1% of people aged 65 and older, although the more advanced form of the disease was more common among diabetes patients aged 65 and older than in people aged 40 to 64.
“These estimates provide policy makers updated information for use in planning eye care services and rehabilitation,” the authors write. “With the aging of the population and the increasing proportion of the population with diverse racial/ethnic heritage, the number of cases of diabetic retinopathy and vision-threatening diabetic retinopathy will likely increase. Furthermore, the need for eye care and for culturally appropriate interventions that can reduce disparity and improve access to eye care among diverse populations is also likely to increase.”