Diabetic Eye Disease

Bressler SB, Edwards AR, Andreoli CM, Edwards PA, Glassman AR, Jaffe GJ, Melia M, Sun JK, for the Committee DRCRN/W. Reproducibility of Optovue RTVue Optical Coherence Tomography Retinal Thickness Measurements and Conversion to Equivalent Zeiss Stratus Metrics in Diabetic Macular Edema. Transl Vis Sci Technol 2015;4(1):5.Abstract

PURPOSE: To evaluate the reproducibility of central subfield thickness (CST) and volume measurements from optical coherence tomography (OCT) images obtained with Zeiss Stratus and Optovue RTVue, and formulate equations to convert these measurements from RTVue to 'equivalent' Stratus values. METHODS: Cross-sectional observational study from 309 eyes of 167 participants with diabetes and at least one eye with central-involved diabetic macular edema (DME; Stratus CST ≥ 250 μm) that underwent two replicate Stratus scans followed by two replicate RTVue scans centered on the fovea. RESULTS: The Bland-Altman coefficient of repeatability for relative change in CST (the degree of change that could be expected from measurement variability) was not significantly different on Stratus and RTVue scans (10% and 16%, respectively). The replicate Stratus CST was within 10% of the initial Stratus measurement 93% of the time; the CST conversion equation predicted a Stratus value calculated from the observed RTVue value within 10% of the observed Stratus thickness 91% of the time. Bland-Altman limit of agreement for relative change in CST between measurements observed on different machines was 23%, comparing predicted versus actual Stratus measurement. CONCLUSIONS: RTVue thickness reproducibility appears similar to Stratus. Conversion equations to transform RTVue measurements to Stratus-equivalent values within 10% of the observed Stratus RT are feasible. CST changes greater than 10% when using the same machine or 20% when switching from Stratus to RTVue, after conversion to Stratus equivalents, are likely due to a true change beyond measurement error. TRANSLATIONAL RELEVANCE: Conversion equations to translate central retinal thickness measurements between OCT instruments is critical to clinical trials.

Lim LS, Ling LH, Cheung CMG, Ong PG, Gong L, Tai SE, Mathur R, Wong D, Foulds W, Wong TY. Relationship of systemic endothelial function and peripheral arterial stiffness with diabetic retinopathy. Br J Ophthalmol 2015;99(6):837-41.Abstract

BACKGROUND: To investigate possible associations between diabetic retinopathy (DR) and systemic vascular endothelial function and arterial stiffness measured using reactive hyperaemia peripheral arterial tonometry. METHODS: This was a cross-sectional observational clinical study. Subjects with diabetes were recruited and DR was graded from retinal photographs. Systemic endothelial function was measured using reactive hyperaemia peripheral arterial tonometry (EndoPAT) and expressed as the reactive hyperaemia index (RHI). Peripheral arterial stiffness was measured using the same device and expressed as the augmentation index (AI). RESULTS: In total, 164 eyes of 95 Chinese patients were evaluated. The mean age of the subject eyes was 60.1±8.2 years and 76.8% were men. The mean duration of diabetes was 15.5±9.8 years, and the mean HbA1c was 8.1±1.4%. In age-gender-adjusted models, increasing severity of DR was associated with increasing mean RHI (p=0.001) and increasing mean AI (p<0.001). In multivariate models, adjusting additionally for smoking, mean duration of diabetes, HbA1c and hypertension, the associations with RHI and AI persisted (p=0.011 and 0.001, respectively). In analyses of the dichotomous outcomes clinically significant macular oedema (CSME), moderate DR and vision-threatening DR, AI was a significant predictor of CSME and vision-threatening DR. In multivariate-adjusted models, for every SD increase in AI, the odds of having CSME was 1.78 times higher (95% CI 1.05 to 2.99; p=0.029). For every SD increase in AI, the odds of having vision-threatening DR was 1.73 times higher (95% CI 1.17 to 2.56; p=0.003). CONCLUSIONS: Subjects with more severe DR have larger peripheral reactive hyperaemic responses and greater peripheral vascular stiffness. These findings support the link between the microvascular changes of diabetes and macrovascular disease.

Santiago JG, Walia S, Sun JK, Cavallerano JD, Haddad ZA, Aiello LP, Silva PS. Influence of diabetes and diabetes type on anatomic and visual outcomes following central rein vein occlusion. Eye (Lond) 2014;28(3):259-68.Abstract
PURPOSE: To determine the influence of diabetes and diabetes type on ocular outcomes following central retinal vein occlusion (CRVO). METHODS: Retrospective chart review of all patients evaluated over a 4-year period in a tertiary diabetes eye care center. Ophthalmic findings were recorded including visual acuity and the presence of retinal neovascularization at presentation, after 3-6 months, and at last follow-up. RESULTS: The records of 19,648 patients (13,571 diabetic; 6077 nondiabetic) were reviewed. The prevalence of CRVO in diabetic patients (N=72) and nondiabetic patients (N=27) were 0.5 and 0.4%, respectively. Disc neovascularization (21.3 vs 0.0%, P=0.05) and panretinal photocoagulation (PRP) (48.7 vs 21.4%, P=0.01) were more common in diabetic patients compared with nondiabetic patients. Compared with type 2 diabetic patients, retinal neovascularization (28.6 vs 3.7%, P=0.004) and subsequent PRP (78.6 vs 41.9%, P=0.01) were more likely in type 1 patients. Optic nerve head collateral vessels (CVs) were observed less than half as often (21.4 vs 56.5%, P=0.04) in patients with type 1 diabetes. Presence of optic nerve head CVs at baseline was associated with less likelihood of PRP (14.3 vs 46.1%, P=0.03). CONCLUSIONS: In this cohort, the rates of CRVO in diabetic and nondiabetic patients were similar to previously published population-based studies. Following CRVO, diabetic patients had higher rates of disc neovascularization and were more likely to require subsequent PRP than nondiabetic patients. As compared with CRVO patients with type 2 diabetes, patients with type 1 diabetes and CRVO had worse anatomic outcomes with substantially increased risks of retinal neovascularization and PRP; however, final visual acuity outcomes were similar.
Sun D, Nakao S, Xie F, Zandi S, Bagheri A, Kanavi MR, Samiei S, Soheili Z-S, Frimmel S, Zhang Z, Ablonczy Z, Ahmadieh H, Hafezi-Moghadam A. Molecular imaging reveals elevated VEGFR-2 expression in retinal capillaries in diabetes: a novel biomarker for early diagnosis. FASEB J 2014;28(9):3942-51.Abstract
Diabetic retinopathy (DR) is a microvascular complication of diabetes and a leading cause of vision loss. Biomarkers and methods for early diagnosis of DR are urgently needed. Using a new molecular imaging approach, we show up to 94% higher accumulation of custom designed imaging probes against vascular endothelial growth factor receptor 2 (VEGFR-2) in retinal and choroidal vessels of diabetic animals (P<0.01), compared to normal controls. More than 80% of the VEGFR-2 in the diabetic retina was in the capillaries, compared to 47% in normal controls (P<0.01). Angiography in rabbit retinas revealed microvascular capillaries to be the location for VEGF-A-induced leakage, as expressed by significantly higher rate of fluorophore spreading with VEGF-A injection when compared to vehicle control (26±2 vs. 3±1 μm/s, P<0.05). Immunohistochemistry showed VEGFR-2 expression in capillaries of diabetic animals but not in normal controls. Macular vessels from diabetic patients (n=7) showed significantly more VEGFR-2 compared to nondiabetic controls (n=5) or peripheral retinal regions of the same retinas (P<0.01 in both cases). Here we introduce a new approach for early diagnosis of DR and VEGFR-2 as a molecular marker. VEGFR-2 could become a key diagnostic target, one that might help to prevent retinal vascular leakage and proliferation in diabetic patients.
Srinivasan PP, Kim LA, Mettu PS, Cousins SW, Comer GM, Izatt JA, Farsiu S. Fully automated detection of diabetic macular edema and dry age-related macular degeneration from optical coherence tomography images. Biomed Opt Express 2014;5(10):3568-77.Abstract

We present a novel fully automated algorithm for the detection of retinal diseases via optical coherence tomography (OCT) imaging. Our algorithm utilizes multiscale histograms of oriented gradient descriptors as feature vectors of a support vector machine based classifier. The spectral domain OCT data sets used for cross-validation consisted of volumetric scans acquired from 45 subjects: 15 normal subjects, 15 patients with dry age-related macular degeneration (AMD), and 15 patients with diabetic macular edema (DME). Our classifier correctly identified 100% of cases with AMD, 100% cases with DME, and 86.67% cases of normal subjects. This algorithm is a potentially impactful tool for the remote diagnosis of ophthalmic diseases.

Ip MS, Domalpally A, Sun JK, Ehrlich JS. Long-term Effects of Therapy with Ranibizumab on Diabetic Retinopathy Severity and Baseline Risk Factors for Worsening Retinopathy. Ophthalmology 2014;Abstract

PURPOSE: To assess the effects of intravitreal ranibizumab on diabetic retinopathy (DR) severity when administered for up to 3 years, evaluate the effect of delayed initiation of ranibizumab therapy on DR severity, and identify baseline patient characteristics associated with the development of proliferative DR (PDR). DESIGN: Exploratory analyses of phase III, randomized, double-masked, sham-controlled multicenter clinical trials. PARTICIPANTS: Adults with diabetic macular edema (DME) (N = 759), baseline best-corrected visual acuity 20/40 to 20/320 Snellen equivalent, and central foveal thickness ≥275 μm. METHODS: Patients were randomized to monthly 0.3 or 0.5 mg ranibizumab or sham injections. Sham participants could switch to 0.5 mg ranibizumab during the third year (sham/0.5 mg crossover). Baseline risk factors were evaluated to explore potential associations with development of PDR. Time to first development of PDR was analyzed by Kaplan-Meier methods to calculate cumulative probabilities by group. MAIN OUTCOME MEASURES: Study eye change on the Early Treatment Diabetic Retinopathy Study severity scale and a composite clinical outcome evaluating progression to PDR based on photographic changes plus clinically important events defining PDR. RESULTS: At month 36, a greater proportion of ranibizumab-treated eyes had ≥2- or ≥3-step DR improvement compared with sham/0.5 mg crossover. A ≥3-step improvement was achieved at 36 months by 3.3%, 15.0%, and 13.2% of sham/0.5 mg, 0.3 mg, and 0.5 mg ranibizumab-treated eyes, respectively (P < 0.0001). Through 36 months, 39.1% of eyes in the sham/0.5 mg group developed PDR, as measured by composite outcome, compared with 18.3% and 17.1% of eyes treated with 0.3 or 0.5 mg ranibizumab, respectively. The presence of macular capillary nonperfusion at baseline seems to be associated with progression to PDR in ranibizumab-treated eyes but did not meaningfully influence visual acuity improvement in eyes with DME after ranibizumab therapy. CONCLUSIONS: Ranibizumab, as administered to patients with DME for 12 to 36 months in these studies, can both improve DR severity and prevent worsening. Prolonged delays in initiation of ranibizumab therapy may limit this therapeutic effect. Although uncommon, the development of PDR still occurs in a small percentage of eyes undergoing anti-vascular endothelial growth factor therapy and may be related to the presence of macular nonperfusion.

Sun JK, Lin MM, Lammer J, Prager S, Sarangi R, Silva PS, Aiello LP. Disorganization of the retinal inner layers as a predictor of visual acuity in eyes with center-involved diabetic macular edema. JAMA Ophthalmol 2014;132(11):1309-16.Abstract

IMPORTANCE: Biomarkers that predict future visual acuity (VA) in eyes with baseline diabetic macular edema (DME) would substantively improve risk assessment, management decisions, and selection of eyes for clinical studies targeting DME. OBJECTIVE: To determine whether baseline or early change in the novel spectral domain-optical coherence tomography (SD-OCT) parameter disorganization of the retinal inner layers (DRIL) is predictive of VA in eyes with center-involved DME. DESIGN, SETTING, AND PARTICIPANTS: At a tertiary care referral center for diabetic eye disease, a retrospective, longitudinal cohort study obtained demographics, VA, and SD-OCT images from baseline, 4-month, and 8-month visits in 96 participants (120 eyes) with diabetes mellitus and baseline center-involved DME (SD-OCT central subfield thickness, ≥ 320 µm for men and ≥ 305 µm for women). Exclusion criteria included substantial media opacity, cataract surgery within 6 months, and nondiabetic retinal pathology affecting VA. On SD-OCT, the 1-mm-wide retinal area centered on the fovea was evaluated by masked graders for DRIL extent, cysts, hyperreflective foci, microaneurysms, cone outer segment tip visibility, and external limiting membrane or photoreceptor disruption and reflectivity. MAIN OUTCOMES AND MEASURES: Visual acuity and SD-OCT-derived retinal morphology. RESULTS: Greater DRIL extent at baseline correlated with worse baseline VA (point estimate, 0.04; 95% CI, 0.02-0.05 per 100 µm; P < .001). An increase in DRIL during 4 months was associated with VA worsening at 8 months (point estimate, 0.03; 95% CI, 0.02-0.05 per 100 µm; P < .001). A multivariate model that included a 4-month change in VA, DRIL, and external limiting membrane disruption was predictive of an 8-month VA change (r = 0.80). Each approximately 300-µm DRIL increase during 4 months predicted a 1-line, 8-month VA decline. When DRIL increased at least 250 µm at 4 months, no eyes had VA improvement of at least 1 line at 8 months. When DRIL decreased at least 250 µm at 4 months, no eyes had VA decline of at least 1 line at 8 months, and 77.7% had VA improvement of at least 1 line. CONCLUSIONS AND RELEVANCE: Disorganization of the retinal inner layers in the 1-mm foveal area is associated with VA, and change in DRIL predicts future change in VA. Early change in DRIL prospectively identifies eyes with a high likelihood of subsequent VA improvement or decline. Therefore, DRIL warrants further study as a robust, readily obtained, and noninvasive biomarker of future VA response in eyes with DME.

Hernandez SL, Gong JH, Chen L, Wu I-H, Sun JK, Keenan HA, King GL. Characterization of circulating and endothelial progenitor cells in patients with extreme-duration type 1 diabetes. Diabetes Care 2014;37(8):2193-201.Abstract

OBJECTIVE: We characterized and correlated endothelial progenitor cells (EPCs) and circulating progenitor cells (CPCs) with lack of vascular complications in the Joslin Medalist Study in patients with type 1 diabetes for 50 years or longer. RESEARCH DESIGN AND METHODS: EPC and CPC levels were ascertained by flow cytometry and compared among Medalists (n = 172) with or without diabetic retinopathy (DR; n = 84 of 162), neuropathy (n = 94 of 165), diabetic nephropathy (DN; n = 18 of 172), cardiovascular disease (CVD; n = 63 of 168), age-matched controls (n = 83), type 2 diabetic patients (n = 36), and younger type 1 diabetic patients (n = 31). Mitogens, inflammatory cytokines, and oxidative markers were measured in blood or urine. Migration of cultured peripheral blood mononuclear cells (PBMCs) from Medalists and age-matched controls were compared. RESULTS: Medalists' EPC and CPC levels equaled those of their nondiabetic age-matched controls, were 10% higher than those in younger type 1 diabetic patients, and were 20% higher than those in age-matched type 2 diabetic patients. CPC levels were 15% higher in Medalists without CVD and nephropathy than in those affected, whereas EPC levels were significantly higher in those without peripheral vascular disease (PVD) than those with PVD. Stromal-derived factor 1 (SDF-1) levels were higher in Medalists with CVD, DN, and DR than in those not affected and their controls. IGF-I levels were lower in Medalists and correlated inversely with CPC levels. Additionally, cultured PBMCs from Medalists migrated more than those from nondiabetic controls. CONCLUSIONS: Normal levels of EPC and CPC in the Medalists, unlike other groups with diabetes, especially those without CVD, support the idea that endogenous factors exist to neutralize the adverse effects of metabolic abnormalities of diabetes on vascular tissues.

Pemp B, Deák G, Prager S, Mitsch C, Lammer J, Schmidinger G, Scholda C, Schmidt-Erfurth U, Bolz M, Bolz M. Distribution of intraretinal exudates in diabetic macular edema during anti-vascular endothelial growth factor therapy observed by spectral domain optical coherence tomography and fundus photography. Retina 2014;34(12):2407-15.Abstract
PURPOSE: To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema. METHODS: Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography. RESULTS: Before treatment, microexudates were detected by SD-OCT as hyperreflective foci in 24 eyes, whereas HEs were seen in 22 eyes. During therapy, HE increased significantly in number and size. This was accompanied by accumulation of microexudates in the outer retina. Enlargement of hyperreflective structures in SD-OCT was accompanied by enlargement of HE at corresponding fundus locations. A rapid reduction in diabetic macular edema was seen in all patients, but to varying degrees. Patients with hemoglobin A1c levels <7% and serum cholesterol <200 mg/dL formed fewer HEs and featured more edema reduction and visual acuity gain. CONCLUSION: Diabetic macular edema reduction during intravitreal anti-vascular endothelial growth factor therapy was accompanied by dynamic rearrangement of intraretinal exudates at corresponding locations in fundus photography and SD-OCT. Intraretinal aggregates of microexudates detectable as hyperreflective foci by SD-OCT may compose and precede HE before they become clinically visible.
Lee WJ, Sobrin L, Kang MH, Seong M, Kim YJ, Yi J-H, Miller JW, Cho HY. Ischemic diabetic retinopathy as a possible prognostic factor for chronic kidney disease progression. Eye (Lond) 2014;28(9):1119-25.Abstract
PURPOSE: To assess the value of diabetic retinopathy (DR) severity as a possible predictive prognostic factor for the progression of chronic kidney disease (CKD). PATIENTS AND METHODS: Retrospective cohort study. Patients (51) who were initially diagnosed with DR and CKD were enrolled and their medical records were evaluated. The following ophthalmic factors were assessed by fluorescein angiography at the initial visit: area of capillary nonperfusion, presence of neovascularization and vitreous hemorrhage, and DR grade. The effect of these factors on CKD progression over the 2-year period of the study, defined as doubling of serum creatinine or the development of end-stage renal disease requiring dialysis or renal transplant, was evaluated. RESULTS: The study included 51 patients with DR and CKD; of these, 11 patients (21.6%) were found to have proliferative DR (PDR) and seven patients (13.7%) had high-risk PDR at baseline. Patients with ischemic DR, who showed extensive capillary nonperfusion (≥ 10 optic disc areas) in the retina, had a greater risk for CKD progression (hazard ratio = 6.64; P = 0.002). CONCLUSION: We found that extensive capillary nonperfusion in the retina greatly increased the risk of progression of CKD in patients with DR. This suggests that the retina and the kidney may have shared risk factors for microvascular disease secondary to diabetes mellitus, and emphasizes the need for a team approach to diabetes care.
Silva PS, Diala PA, Hamam RN, Arrigg PG, Shah ST, Murtha TL, Schlossman DK, Cavallerano JD, Sun JK, Aiello LP. Visual outcomes from pars plana vitrectomy versus combined pars plana vitrectomy, phacoemulsification, and intraocular lens implantation in patients with diabetes. Retina 2014;34(10):1960-8.Abstract

PURPOSE: To compare visual acuity outcomes and diabetic retinopathy progression after pars plana vitrectomy (PPV) versus combined pars plana vitrectomy and phacoemulsification (PPVCE) in patients with diabetes. METHODS: Retrospective review of 222 consecutive diabetic patients undergoing PPV or PPVCE. RESULTS: A total of 251 eyes of 222 patients were evaluated (PPV = 122, PPVCE = 129). Four-year follow-up was 64% (161 eyes). Overall, patients undergoing PPVCE had better preoperative visual acuity (PPVCE = 20/80, PPV = 20/160, P = 0.03). At 4-year follow-up, visual acuity improved (PPV = +22, PPVCE = +11 letters) compared with baseline in both groups. After correcting for baseline differences in visual acuity, no statistically significant difference in final visual acuity was observed (PPVCE = 20/32, PPV = 20/50, P = 0.09). Results did not differ substantially by surgical indication (vitreous hemorrhage, traction retinal detachment, epiretinal membrane, and/or diabetic macular edema). Cataract progression occurred in 64%, and cataract surgery was performed in 39% of phakic eyes undergoing PPV. Rates of diabetic retinopathy progression, vitreous hemorrhage, and retinal detachment were not statistically different. Neovascular glaucoma developed in 2 patients (2%) after PPV and 6 patients (8%) after PPVCE (P = 0.07). CONCLUSION: In diabetic patients, equivalent visual acuity improvement over 4 years was observed after PPV or PPVCE. Visual outcomes and retinopathy progression rates were not significantly different after either intervention, suggesting that PPVCE may be appropriate when indicated in patients with diabetes.

Valdez CN, Arboleda-Velasquez JF, Amarnani DS, Kim LA, D'Amore PA. Retinal microangiopathy in a mouse model of inducible mural cell loss. Am J Pathol 2014;184(10):2618-26.Abstract
Diabetes can lead to vision loss because of progressive degeneration of the neurovascular unit in the retina, a condition known as diabetic retinopathy. In its early stages, the pathology is characterized by microangiopathies, including microaneurysms, microhemorrhages, and nerve layer infarcts known as cotton-wool spots. Analyses of postmortem human retinal tissue and retinas from animal models indicate that degeneration of the pericytes, which constitute the outer layer of capillaries, is an early event in diabetic retinopathy; however, the relative contribution of specific cellular components to the pathobiology of diabetic retinopathy remains to be defined. We investigated the phenotypic consequences of pericyte death on retinal microvascular integrity by using nondiabetic mice conditionally expressing a diphtheria toxin receptor in mural cells. Five days after administering diphtheria toxin in these adult mice, changes were observed in the retinal vasculature that were similar to those observed in diabetes, including microaneurysms and increased vascular permeability, suggesting that pericyte cell loss is sufficient to trigger retinal microvascular degeneration. Therapies aimed at preventing or delaying pericyte dropout may avoid or attenuate the retinal microangiopathy associated with diabetes.
Arboleda-Velasquez JF, Primo V, Graham M, James A, Manent J, D'Amore PA. Notch signaling functions in retinal pericyte survival. Invest Ophthalmol Vis Sci 2014;55(8):5191-9.Abstract
PURPOSE: Pericytes, the vascular cells that constitute the outer layer of capillaries, have been shown to have a crucial role in vascular development and stability. Loss of pericytes precedes endothelial cell dysfunction and vascular degeneration in small-vessel diseases, including diabetic retinopathy. Despite their clinical relevance, the cellular pathways controlling survival of retinal pericytes remain largely uncharacterized. Therefore, we investigated the role of Notch signaling, a master regulator of cell fate decisions, in retinal pericyte survival. METHODS: A coculture system of ligand-dependent Notch signaling was developed using primary cultured retinal pericytes and a mesenchymal cell line derived from an inducible mouse model expressing the Delta-like 1 Notch ligand. This model was used to examine the effect of Notch activity on pericyte survival using quantitative PCR (qPCR) and a light-induced cell death assay. The effect of Notch gain- and loss-of-function was analyzed in monocultures of retinal pericytes using antibody arrays to interrogate the expression of apoptosis-related proteins. RESULTS: Primary cultured retinal pericytes differentially expressed key molecules of the Notch pathway and displayed strong expression of canonical Notch/RBPJK (recombination signal-binding protein 1 for J-kappa) downstream targets. A gene expression screen using gain- and loss-of-function approaches identified genes relevant to cell survival as downstream targets of Notch activity in retinal pericytes. Ligand-mediated Notch activity protected retinal pericytes from light-induced cell death. CONCLUSIONS: Our results have identified signature genes downstream of Notch activity in retinal pericytes and suggest that tight regulation of Notch signaling is crucial for pericyte survival.
Lee WJ, Sobrin L, Lee MJ, Kang MH, Seong M, Cho H. The relationship between diabetic retinopathy and diabetic nephropathy in a population-based study in Korea (KNHANES V-2,3). Invest Ophthalmol Vis Sci 2014;Abstract

PURPOSE. To determine the risk factors for and relationship between diabetic retinopathy (DR) and diabetic nephropathy (DN), including microalbuminuria and overt nephropathy, in a population-based study of diabetes mellitus (DM) patients in Korea. METHODS. This was a population-based, cross-sectional study. From the fifth (2011, 2012) Korea National Health and Nutrition Examination Survey (KNHANES), 971 participants with type 2 DM were included. The prevalence of DR and DN was determined. Multivariate logistic regression was performed to determine risk factors, including DR, associated with DN in the Korean population. RESULTS. In DM patients, we observed a prevalence of 20.0% for any DR and 3.8% for proliferative diabetic retinopathy (PDR). Microalbuminuria prevalence was 19.3% and overt nephropathy prevalence was 5.5%. The risk factors of microalbuminuria were presence of hypertension, higher systolic blood pressure, serum hemoglobin A1c (HbA1c) and serum blood urea nitrogen level as well as the presence of PDR. The risk factors of overt nephropathy were long duration of DM, high levels of HbA1c, systolic blood pressure, total cholesterol and serum creatinine as well as the presence of DR. CONCLUSIONS. PDR is associated with microalbuminuria and DR is associated with overt nephropathy in Korean DM patients. Our findings suggest that when an ophthalmologist finds the presence of DR or PDR, timely evaluation of the patient's renal status should be recommended.

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