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Re: Wang et al.: Incidence and risk factors for developing diabetic retinopathy among youths with type 1 or type 2 diabetes throughout the United States (Ophthalmology. 2017;124:424-430)

      To the Editor:
      We read with interest the article by Wang et al.
      • Wang S.Y.
      • Andrews C.A.
      • Herman W.H.
      • et al.
      Incidence and risk factors for developing diabetic retinopathy among youths with type 1 or type 2 diabetes throughout the United States.
      In this retrospective, observational, longitudinal cohort study derived from a large, insurance-derived billing and coding originated database (OptiumInsight, Eden Prairie, MN) that examined records from individuals under age 21, the authors report on subjects for a median of approximately 3 years. There were 2240 patients with type I diabetes and 1786 with type 2 diabetes. International Classification of Diseases, 9th edition, coding criteria were used to support diagnosis and severity.
      Based on their analysis, the authors conclude that youth are at considerable risk for diabetic retinopathy (DR) and should undergo regular screening by eye care professionals to ensure timely diagnosis and limit progression to vision-threatening disease. The authors
      • Wang S.Y.
      • Andrews C.A.
      • Herman W.H.
      • et al.
      Incidence and risk factors for developing diabetic retinopathy among youths with type 1 or type 2 diabetes throughout the United States.
      believe that the recommendations from both the American Diabetes Association and the American Academy of Ophthalmology screening recommendations are insufficient and based on only limited data.
      We believe that their data do not meet criteria for changing our current Preferred Practice Pattern recommendations. The important issue to address in making this determination is the strength and design of the study. Wang et al suggest that, “Detecting DR in youths relatively early in its course, before vision threatened or interventions are required, can be beneficial, as providers can increase monitoring intensity, improve glycemic control, and coordinate care among eye-care providers, pediatricians, and endocrinologists to avert or delay poor long-term visual outcomes.”
      • Wang S.Y.
      • Andrews C.A.
      • Herman W.H.
      • et al.
      Incidence and risk factors for developing diabetic retinopathy among youths with type 1 or type 2 diabetes throughout the United States.
      Interestingly, in their study, they found that, “No patient with [type 1 or 2 diabetes] underwent panretinal photocoagulation, focal laser treatment, or intravitreal injections.”
      Although we agree, and there is little debate, that optimizing blood glucose control is beneficial and has been clearly demonstrated to lower the rate of retinopathy,
      The relationship of glycemic exposure (HbA1c) to the risk of development and progression of retinopathy in the diabetes control and complications trial.
      do the data presented by Wang et al supply sufficient evidence to suggest that by getting earlier screening, by an eye care provider, will affect the progression of retinopathy? Screening is expensive, time consuming, and without sufficient evidence to support a benefit when none of the subjects in their study needed any form of ophthalmologic treatment.
      First, let us examine where the existing screening data originate. Current data are based on high-quality, population-based epidemiologic studies. Klein et al
      • Klein R.
      • Klein B.E.
      • Moss S.E.
      • et al.
      The Wisconsin epidemiologic study of diabetic retinopathy. II. Prevalence and risk of diabetic retinopathy when age at diagnosis is less than 30 years.
      reported on 996 insulin-taking, younger-onset diabetics in a population from Wisconsin (Wisconsin Epidemiologic Study of Diabetic Retinopathy [WESDR]). Subjects underwent extensive testing (hemoglobin A1c, etc) and had 7-field, stereoscopic color fundus photographs. The level of DR was classified into 8 categories and subcategories. Figure 2 from their article demonstrates the comparison of any DR (%) versus proliferative retinopathy over time (duration of diabetes). Klein et al found that the rate of any retinopathy is actually quite similar to Wang et al, especially at 5 years, where the incidence is approximately 30%. Note that the category of “any retinopathy” could include a simple intraretinal hemorrhage or a single microaneurysm. The level of categorizing the DR in WESDR was highly reliable (fundus photographs) and carefully categorized. Neither study found proliferative retinopathy or macular edema requiring treatment in any case of type 1 diabetes of <5 years' duration.
      The data from Wang et al are based on insurance data that were retrospective in nature, and dependent on clinicians coding DR according to International Classification of Diseases, 9th edition, standards. Such a categorization of DR is inherently less accurate, subject to coding bias, and lacks the objectivity of a photograph. Nevertheless, the data collected nicely correlate with the data on progression from the 1984 study by Klein.
      • Klein R.
      • Klein B.E.
      • Moss S.E.
      • et al.
      The Wisconsin epidemiologic study of diabetic retinopathy. II. Prevalence and risk of diabetic retinopathy when age at diagnosis is less than 30 years.
      Wang et al effectively use an insurance database to support our existing screening recommendations and report other interesting features that are beneficial for management of young diabetics. Thus, we completely agree that aggressively managing systemic glucose levels and optimizing hemoglobin A1c levels are very important, yet we do not agree that more frequent eye examinations or changing the Preferred Practice Pattern recommendations are warranted based on these new data, especially when there is no treatable pathology demonstrated during this time period. We also wish to stress that the population-based studies
      • Klein R.
      • Klein B.E.
      • Moss S.E.
      • et al.
      The Wisconsin epidemiologic study of diabetic retinopathy. II. Prevalence and risk of diabetic retinopathy when age at diagnosis is less than 30 years.
      • Klein R.
      • Klein B.E.
      • Moss S.E.
      • et al.
      The Wisconsin epidemiologic study of diabetic retinopathy. III. Prevalence and risk of diabetic retinopathy when age at diagnosis is 30 or more years.
      • Klein R.
      • Klein B.E.
      • Moss S.E.
      • et al.
      The Wisconsin epidemiologic study of diabetic retinopathy. IV. Diabetic macular edema.
      on which these recommendations are based are highly relevant and utilize sound methodology.

      References

        • Wang S.Y.
        • Andrews C.A.
        • Herman W.H.
        • et al.
        Incidence and risk factors for developing diabetic retinopathy among youths with type 1 or type 2 diabetes throughout the United States.
        Ophthalmology. 2017; 124: 424-430
      1. The relationship of glycemic exposure (HbA1c) to the risk of development and progression of retinopathy in the diabetes control and complications trial.
        Diabetes. 1995; 44: 968-983
        • Klein R.
        • Klein B.E.
        • Moss S.E.
        • et al.
        The Wisconsin epidemiologic study of diabetic retinopathy. II. Prevalence and risk of diabetic retinopathy when age at diagnosis is less than 30 years.
        Arch Ophthalmol. 1984; 102: 520-526
        • Klein R.
        • Klein B.E.
        • Moss S.E.
        • et al.
        The Wisconsin epidemiologic study of diabetic retinopathy. III. Prevalence and risk of diabetic retinopathy when age at diagnosis is 30 or more years.
        Arch Ophthalmol. 1984; 102: 527-532
        • Klein R.
        • Klein B.E.
        • Moss S.E.
        • et al.
        The Wisconsin epidemiologic study of diabetic retinopathy. IV. Diabetic macular edema.
        Ophthalmology. 1984; 91: 1464-1474

      Linked Article

      • Incidence and Risk Factors for Developing Diabetic Retinopathy among Youths with Type 1 or Type 2 Diabetes throughout the United States
        OphthalmologyVol. 124Issue 4
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          Despite the increasing prevalence of type 2 diabetes mellitus (T2DM) among children and adolescents, little is known about their risk of developing diabetic retinopathy (DR). We sought to identify risk factors for DR in youths with diabetes mellitus, to compare DR rates for youths with type 1 diabetes mellitus (T1DM) and those with T2DM, and to assess whether adherence to DR screening guidelines promoted by the American Academy of Ophthalmology, American Academy of Pediatrics, and American Diabetes Association adequately capture youths with DR.
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      • Reply
        OphthalmologyVol. 124Issue 9
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          We appreciate the interest that Drs. Olsen and Lum had in our recent study.1 We agree with them that it would be inappropriate to change the existing American Academy of Ophthalmology Preferred Practice Pattern recommendations for screening for diabetic retinopathy in youth on the basis of the findings of our study alone. Making changes to important guidelines such as these require consensus input from the entire Preferred Practice Pattern Committee, not simply the opinions of 1 or 2 of its members.
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