The incidences of diabetic retinopathy and macular edema are higher in Latinos than in other racial and ethnic groups, according to a population-based study of more than 4,000 individuals.
This finding from the Los Angeles Latino Eye Study (LALES), the largest study to assess the incidence and progression of these disorders in an American Latino population, emphasizes “the importance of timely dilated ophthalmologic examinations for Latinos who have diabetes and are at risk for vision-threatening retinopathy,” said Dr. Rohit Varma of the Doheny Eye Center, Los Angeles, and his associates.
LALES assessed eye disease among 4,658 self-identified Latinos aged 40 years or older living in L.os A. County. Baseline clinical examinations were performed between 2000 and 2003, and 4-year follow-up examinations were performed between 2004 and 2008.
Dr. Rohit and his colleagues examined data for a subset of 775 diabetic subjects participating in LALES.
The overall incidence of diabetic retinopathy in either eye was 34%; the annualized incidence was 7%. In comparison, the annualized incidence was 4% for the largely white population in the Blue Mountains Eye Study; and in two other studies—the Liverpool Diabetic Eye Study and the Australian Diabetes, Obesity, and Lifestyle Study—the overall incidences were 4% and 14%, respectively, and the annualized incidences were less than 1% and less than 3% among whites, respectively.
In LALES, the incidence of retinopathy declined with age. A total of 45% of those in their 40s were affected, vs. 24% of those aged 70 years or older.
The incidence of diabetic retinopathy was nearly twice as high in patients not receiving diabetes treatment (33% vs.17%). Among patients who had any degree of diabetic retinopathy at baseline, the disorder progressed during the study period in 39%. Progression was more likely to occur in younger patients, and was not associated with duration of diabetes.
Fourteen percent of patients who had retinopathy at baseline showed improvement at follow-up. None reported having undergone retinal photocoagulation therapy, “indicating that their improvement was related to some factor other than surgery,” the researchers wrote (Am. J. Ophthalmol. 2010 Feb. 9 [doi:10.1016/j.ajo.2009.11.014]).
At follow-up, “incidence of diabetic retinopathy in the second eye (among those with DR in one eye at baseline) was nearly twice as high as compared to [the] incidence in the first eye (among those with no DR at baseline).
“This finding is significant from a health-related quality-of-life perspective because individuals with disease in only one eye tend to rely heavily on their contralateral eye for daily tasks. When the healthy eye also develops disease, the ability of people to complete vision-related tasks and normal activities becomes severely impaired,” Dr. Varma and his associates wrote.
The overall incidence of macular edema in either eye was 5.4%. The rate of macular edema increased significantly with duration of diabetes: less than 3% among those diagnosed within 1 year vs. 11% in those diagnosed at least 15 years earlier.
The National Institutes of Health and Research to Prevent Blindness Inc. supported the study. The authors reported no conflicts of interest.