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J. K. Sun, H. A. Keenan, J. D. Cavallerano, A. Doria, L. P. Aiello, G. L. King; Historical, Genetic, and Biochemical Risk Factors Predictive of Retinopathy and Visual Acuity in Patients With 50 Years or More of Type 1 Diabetes Mellitus. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5678.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the relationship of historical, genetic, and biochemical risk factors with retinopathy and visual acuity (VA) outcomes in a large cohort of patients who have lived 50 or more years with type 1 diabetes mellitus (DM).
One hundred and eighty-four patients underwent Early Treatment Diabetic Retinopathy Study (ETDRS) VA testing, dilated fundus exam, and ETDRS protocol 7-standard field fundus photography; measurement of hemoglobin A1c (HbA1c), lipids, islet cell antibodies, interleukin-6, and C-peptide; and HLA DQB1, DQA1, and DRB1genotyping. Fundus photos were graded by 2 readers for severity of diabetic retinopathy (DR) and macular edema (ME). Grading discrepancies were adjudicated by a third reader.
In the eye with the more severe level of DR, 7.1 % of patients (13) had no discernible DR, 1.6% (3) had questionable DR, 31.5% (58) had mild nonproliferative DR (NPDR), 9.2% (17) had moderate NPDR, 0.5% (1) had severe NPDR, and 47.8% (88) had proliferative DR (PDR). Four patients (2.2%) had fundus photos that were ungradable in both eyes due to media opacities and/or missing ETDRS fields. Of 88 eyes with PDR, 93.2% had scars from previous scatter photocoagulation and 97.3% had achieved quiescence. Clinically significant ME was apparent in at least one eye in 8.7% of patients. VA was 20/20 or better in 56.0%, 20/40 or better in 96.2%, and 20/200 or worse in 1.6% of patients. After multivariate models were used to test for possible confounders, logistic regression analysis revealed that less severe DR was independently correlated with the presence of any of the three HLA alleles (p = 0.022), the presence of IA2 autoantibodies (p = 0.046), and the absence of microalbuminuria (p = 0.003). Visual acuity of 20/20 or better was correlated with less severe DR (p<0.0001) and lower current HbA1c (p=0.039). Neither DR severity nor VA were significantly related to age, duration of DM, hypertensive status, C-peptide, or lipid levels.
In this cohort of patients with 50 years or more of type 1 DM, an unexpectedly high number (40.2%) have no or mild NPDR and over 50% retain 20/20 VA or better. In addition, biochemical and genetic factors, such as the presence of HLA alleles or IA2 autoantibodies appear correlated with protection against the development of PDR even after 50 years of DM. Subsequent studies of this unique cohort may further elucidate molecular mechanisms that suppress retinopathy and other microvascular complications of diabetes.
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