Diabetes is a developing epidemic that will affect over 700 million people globally by 2045. Diabetes’ rising prevalence affects both children and adults; it is estimated that the number of children and adolescents with type 1 diabetes (T1D) would nearly triple and those with type 2 diabetes (T2D) will nearly quadruple by the year 2050.
While improved patient education and advances in medical care have resulted in improvements in systemic control for populations with diabetes in developed countries such as the United States, the increased global prevalence of diabetes implies that an increasing number of individuals will be at risk for vision loss due to diabetic retinopathy over the next few decades.
These findings emphasize the importance of gaining a better understanding of when and how eye-threatening problems emerge in children and adolescents with diabetes in order to maximize interventions for vision preservation in these vulnerable individuals.
The researchers in this issue of JAMA Ophthalmology address the issue of ocular outcomes in children and young adults with diabetes by conducting a retrospective, population-based medical record review of children and young adults diagnosed with diabetes before the age of 22 in Olmsted County, Minnesota, over a nearly five-decade period.
The researchers extended 15-year Kaplan-Meier rates of developing nonproliferative diabetic retinopathy, proliferative diabetic retinopathy, diabetic macular edema, or visually significant cataract, or of undergoing vitrectomy for patients with T1D vs T2D based on data from 461 children with T1D and 64 children with T2D.
They discovered that children with T2D have almost double the risk of acquiring retinopathy as children with T1D, as well as a higher risk of developing proliferative diabetic retinopathy or requiring vitrectomy in the long run. According to the authors, the natural history of retinopathy may differ between T1D and T2D patients.
The Mayo Clinic has offered residents of Olmsted County, Minnesota, with medical care continuity for decades, with 86.6 percent of residents having undergone at least one eye checkup. Beyond the variety of clinical follow-up and missing observations commonly observed in a retrospective assessment of medical records, the data also has limitations.
Kaplan-Meier estimates of retinopathy outcomes at 15 to 30 years may not be totally stable if many previous observations have been censored. This is especially true for the T2D cohort, which has only 64 members. Assuming the data are normally distributed, the mean (SD) of follow-up duration (13.6 [9.4] years for T1D and 8.6 [6,9] years for T2D) indicates there were only 16 percent of patients with T1D who had follow-up beyond 23 years, and 15.5 years for those with T2D.
As a result, long-term risk predictions may not be as accurate as short-term ones. A fundus photograph of the eye was only reviewed for the severity of diabetic retinopathy in the absence of a clinical examination, which is why most diagnoses relied on clinical evaluation. Retinal pathology in diabetics may have gone undetected or unreported.
During the time of the study, clinical management and grading of diabetic eye disease underwent significant changes. As early as the late 1960s, the Airlie House classification for diabetic retinopathy was developed, and the current reference standard Early Treatment Diabetic Retinopathy severity scale was not published until 1991. As a covariate in Cox proportional hazard modeling, hemoglobin A1c readings from 1970 to 2019 were documented whenever they were available at the time of diabetes diagnosis and at each subsequent examination.
A1c results from before 1996 may not be directly comparable across time because of the National Glycohemoglobin Standardization Program’s inability to routinely peg hemoglobin A1c values to the Diabetes Control and Complications Trial (DCCT) assay that is now the reference standard. The findings from this cohort may not apply to more diverse populations outside of Olmstead County, as the authors point out. The county’s population was 95.7% white in 1990.
The study’s limitations notwithstanding, Bai et al have made an important contribution by highlighting numerous aspects crucial to the development of a comprehensive understanding of diabetic eye disease in both juvenile and adult populations. Setting adequate screening criteria for baseline and follow-up retinal examinations requires accurate risk estimations for the onset of vision-threatening diseases such as proliferative diabetic retinopathy and diabetic macular edema.
Five years after a child is diagnosed with T1D, current recommendations call for a baseline dilated fundus examination. There was no risk of acquiring a vision-threatening condition within five years of diagnosis in both groups in this study, suggesting that this timing may also be optimal for kids with T2D.
Furthermore, this study reaffirms the extremely low chance of developing severe retinopathy before puberty. As a result of these findings, it is imperative to investigate whether there are any changes in ocular outcomes between patients with T1D and T2D and to identify the processes that underlie these disparities. Obesity, blood lipids, and the prevalence of hypertension are all factors that differ significantly across diabetic cohorts with T1D and T2D. It is crucial to know how and whether these factors affect the development or progression of diabetic retinopathy in children and adults. When it comes to T2D patients, there is a lack of data on the outcomes of retinopathy and the risk factors for developing severe illness.
In order to maximize guidelines for baseline screening and subsequent follow-up frequency for young persons diagnosed with diabetes in the current era, similar epidemiologic studies across different, heterogeneous cohorts are required. Efforts like this may lead to a better knowledge of the variations in pathophysiology between T1D and T2D, which could lead to new treatment targets for the preservation of vision in young diabetics.
Source: JAMA Network
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