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By Nancy Walsh, Staff Writer, MedPage Today Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse PlannerNote that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.In this study of young people with type 2 diabetes, retinopathy was present in a significant number after approximately 5 years of followup.WASHINGTON -- Retinopathy had already developed within 5 years of the onset of type 2 diabetes in a substantial number of teens with the disease, a researcher reported here.
Among a cohort of patients ages 10 to 17 at baseline, 13.7% had evidence of retinopathy during follow-up of 2 to 6.5 years, according to Lynne L. Levitsky, MD, of Massachusetts General Hospital in Boston, and colleagues.
That's similar to an estimated 15.5% prevalence over 3 years previously identified among adults, Levitsky said at the annual meeting of the Pediatric Endocrine Society.
The finding emerged from the TODAY study, an NIH-funded multicenter intervention trial that included 699 young patients with type 2 diabetes.
"The detailed characterization of the early course of retinopathy in adults with type 2 diabetes has been hindered by the long lag time after diagnosis. We sought to more closely examine the natural history of this in younger patients," Levitsky said.
To do that, the researchers obtained digital fundus photographs for 517 of the TODAY participants. They were classified as having retinopathy if one or more retinal lesions were present in at least one eye.
The types of lesions included microaneurysms, intraretinal hemorrhages, and cotton wool infarcts.
At the time of retinal examination, patients' average age was 18.1. Two-thirds were female, all were overweight or obese, and 80% were minorities.
Mean body mass index (BMI) was 36, and average hemoglobin (Hb) A1c was 7.1%.
All patients with retinopathy had mild nonproliferative changes, and none had macular edema.
Factors that were associated with an increased risk of retinopathy included disease control, age, and duration of disease.
"There was a gradual, significant increase in the prevalence of retinopathy depending on HbA1c such that those in the lowest tertile had a prevalence of retinopathy of 4.7%, rising to 12.4% in the middle tertile and to 25% in those with the most poorly controlled disease," she said.
Compared with the lowest tertile of HbA1c, odds of retinopathy in patients with higher concentrations were: Tertile 2, OR 2.497 (95% CI 1.058 to 5.894)Tertile 3, OR 6.311 (95% CI 2.840 to 14.023)
For patients ages 12 to 16, the prevalence of retinopathy was 5.7%, increasing to 12.4% in those ages 17 to 18, and to 19% for those 19 to 24.
The odds ratio in the oldest group was 3.005 (95% CI 1.270 to 7.112), which was statistically significant, according to Levitsky.
Prevalence was 5.3% among those who had had diabetes for 24 to 49 months, reaching 22.3% for those with disease duration ranging from 67 to 101 months (OR 3.649, 95% CI 1.5 to 8.8).
"But the most interesting finding was that there was no difference in prevalence of retinopathy between patients in the lower ranges of BMI, which was 16.3% in the lowest tertile and 15.6% in the second tertile, and the prevalence was actually lower in the very obese," she said.
For those with a BMI ranging from 37.87 kg/m2 to 68 kg/m2, only 9.3% had retinopathy (OR 3.649, 95% CI 0.377 to 0.810).
"This is known as the obesity paradox, and has been observed in adult retinopathy as well as for adult mortality from heart failure, hypertension, and a number of other conditions," Levitsky said.
But it has not previously been reported in young people, she added.
"We can speculate that extreme insulin resistance in the very obese is in some way protective, but the mechanism is still unknown," she said.
"If we could understand this association, we might separate out the effects of hyperglycemia from the direct effects of insulin or the inflammatory effects of obesity in retinopathy development," she said.
Continuing follow-up of this large cohort of young patients with type 2 diabetes will help define the natural history of the disease and the course of retinopathy, she concluded.
Levitsky has consulted and received support from Novo Nordisk and Eli Lilly.
Primary source: Pediatric Endocrine Society
Source reference:
Levitsky L, et al "Prevalence of retinopathy in young people with type 2 diabetes in the TODAY study" PES 2013; Abstract 3490.2.
Nancy Walsh
Staff Writer
Nancy Walsh has written for various medical publications in the United States and England, including Patient Care, The Practitioner, and the Journal of Respiratory Diseases. She also has contributed numerous essays to several books on history and culture, most recently to The Book of Firsts (Anchor Books, 2010).
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