Glycemic exposure and blood pressure influencing progression and remission of diabetic retinopathy: a longitudinal cohort study in GoDARTS

Development and external validation of a predictive model for type 2 diabetic retinopathy

Diabetes retinopathy (DR) is a critical clinical disease with that causes irreversible visual damage in adults, and may even lead to permanent blindness in serious cases. Early identification and treatment of DR is critical. Our aim was to train and externally validate a prediction nomogram for early prediction of DR. 2381 patients with type 2 diabetes mellitus (T2DM) were retrospective study from the First Affiliated Hospital of Xinjiang Medical University in Xinjiang, China, hospitalised between Jan 1, 2019 and Jun 30, 2022. 962 patients with T2DM from the Suzhou BenQ Hospital in Jiangsu, China hospitalised between Jul 1, 2020 to Jun 30, 2022 were considered for external validation. The least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression was performed to identify independent predictors and establish a nomogram to predict the occurrence of DR. The performance of the nomogram was evaluated using a receiver operating characteristic curve (ROC), a calibration curve, and decision curve analysis (DCA). Neutrophil, 25-hydroxyvitamin D3 [25(OH)D3], Duration of T2DM, hemoglobin A1c (HbA1c), and Apolipoprotein A1 (ApoA1) were used to establish a nomogram model for predicting the risk of DR. In the development and external validation groups, the areas under the curve of the nomogram constructed from the above five factors were 0.834 (95%CI 0.820-0.849) and 0.851 (95%CI 0.829-0.874), respectively. The nomogram demonstrated excellent performance in the calibration curve and DCA. This research has developed and externally verified that the nomograph model shows a good predictive ability in assessing DR risk in people with type 2 diabetes. The application of this model will help clinicians to intervene early, thus effectively reducing the incidence rate and mortality of DR in the future, and has far-reaching significance in improving the long-term health prognosis of diabetes patients.

Transition probabilities of diabetic retinopathy and death in an Asian population with diabetes

PURPOSE

To evaluate the dynamic transitions in diabetic retinopathy (DR) severity over time and associated risk factors in an Asian population with diabetes.

DESIGN

Longitudinal cohort study METHODS: We analyzed data from 9481 adults in the Singapore Integrated Diabetic Retinopathy Screening Program (2010-2015) with linkage to death registry. A multistate Markov model adjusted for age, sex, systolic blood pressure (SBP), diabetes duration, HbA1c, and body mass index (BMI) was applied to estimate annual transition probabilities between four DR states (no, mild, moderate, and severe/proliferative) and death, and the mean sojourn time in each state.

RESULTS

The median assessment interval was 12 months, with most patients having 3 assessments. Annual probabilities for DR progression (no-to-mild, mild-to-moderate and moderate-to-severe/proliferative) were 6.1 %, 7.0 % and 19.3 %, respectively; and for regression (mild-to-no, moderate-to-mild and severe-to-moderate) were 55.4 %, 17.3 % and 4.4 %, respectively. Annual mortality rates from each DR state were 1.2 %, 2.0 %, 18.7 %, and 30.0 %. The sojourn time in each state were 8.2, 0.8, 0.8 and 2.2 years. Higher HbA1c and SBP levels were associated with progression of no-mild and mild-moderate DR, and diabetes duration with no-to-mild and moderate-to-severe/proliferative DR. Lower HbA1c levels were associated with regression from mild-to-no and moderate-to-mild, and higher BMI with mild-to-no DR.

CONCLUSIONS

Our results suggest a prolonged duration (∼8 years) in developing mild DR, with faster transitions (within a year) from mild or moderate states. Moderate/above DR greatly increases the probability of progression and death as compared to mild DR/below. HbA1c was associated with both progression as well as regression.

Risk Factors for Diabetic Retinopathy in Latin America (Mexico) and the World: A Systematic Review and Meta-Analysis

Diabetic retinopathy (DR) is one of the main complications of diabetes, and the management of the main control parameters explains only an 11% reduction in the risk of progressing to DR, leaving 89% to be explained by other factors or correlations between the usual factors that are currently unknown. The objective of this systematic review and meta-analysis is to evaluate the similarities and differences between the possible risk factors for developing DR when comparing the world to Latin American populations. The search was performed first for Latin American (LA) populations and a second search for non-Latin American (Non-LA) populations. Using the PRISMA guidelines, five articles were found to be relevant for each of the groups. The patients who had elevated systolic blood pressure (SBP) developed DR more frequently than the patients without retinopathy (Z = 2.1, p = 0.03), an effect measured in the population at a global level (GL), behavior that becomes not significant when the LA and non-LA populations are grouped separately; relevant to this is that the diagnosis of hypertension (HBP) grouped globally and stratified does not present a risk factor for DR (Z = 0.79, p = 0.42). This indicates that SBP is a risk factor for the world population and that, by separating it into different regions, the omission could cause it not to be considered a possible risk factor. In conclusion, the relationship between the increase in DR associated with the risk factors present in different populations, the limited research conducted in Latin America, and the cultural, social, economic, and genetic differences makes for a complex condition, which reflects the necessity of researching in a more integrated way.

Test accuracy of artificial intelligence-based grading of fundus images in diabetic retinopathy screening: A systematic review

OBJECTIVES

To systematically review the accuracy of artificial intelligence (AI)-based systems for grading of fundus images in diabetic retinopathy (DR) screening.

METHODS

We searched MEDLINE, EMBASE, the Cochrane Library and the ClinicalTrials.gov from 1st January 2000 to 27th August 2021. Accuracy studies published in English were included if they met the pre-specified inclusion criteria. Selection of studies for inclusion, data extraction and quality assessment were conducted by one author with a second reviewer independently screening and checking 20% of titles. Results were analysed narratively.

RESULTS

Forty-three studies evaluating 15 deep learning (DL) and 4 machine learning (ML) systems were included. Nine systems were evaluated in a single study each. Most studies were judged to be at high or unclear risk of bias in at least one QUADAS-2 domain. Sensitivity for referable DR and higher grades was ≥85% while specificity varied and was <80% for all ML systems and in 6/31 studies evaluating DL systems. Studies reported high accuracy for detection of ungradable images, but the latter were analysed and reported inconsistently. Seven studies reported that AI was more sensitive but less specific than human graders.

CONCLUSIONS

AI-based systems are more sensitive than human graders and could be safe to use in clinical practice but have variable specificity. However, for many systems evidence is limited, at high risk of bias and may not generalise across settings. Therefore, pre-implementation assessment in the target clinical pathway is essential to obtain reliable and applicable accuracy estimates.

Development and evaluation of a risk prediction model for diabetes mellitus type 2 patients with vision-threatening diabetic retinopathy

Objective

This study aims to develop and evaluate a non-imaging clinical data-based nomogram for predicting the risk of vision-threatening diabetic retinopathy (VTDR) in diabetes mellitus type 2 (T2DM) patients.

Methods

Based on the baseline data of the Guangdong Shaoguan Diabetes Cohort Study conducted by the Zhongshan Ophthalmic Center (ZOC) in 2019, 2294 complete data of T2DM patients were randomly divided into a training set (n=1605) and a testing set (n=689). Independent risk factors were selected through univariate and multivariate logistic regression analysis on the training dataset, and a nomogram was constructed for predicting the risk of VTDR in T2DM patients. The model was evaluated using receiver operating characteristic (ROC) curves and area under the curve (AUC) in the training and testing datasets to assess discrimination, and Hosmer-Lemeshow test and calibration curves to assess calibration.

Results

The results of the multivariate logistic regression analysis showed that Age (OR = 0.954, 95% CI: 0.940-0.969, p = 0.000), BMI (OR = 0.942, 95% CI: 0.902-0.984, p = 0.007), systolic blood pressure (SBP) (OR =1.014, 95% CI: 1.007-1.022, p = 0.000), diabetes duration (10-15y: OR =3.126, 95% CI: 2.087-4.682, p = 0.000; >15y: OR =3.750, 95% CI: 2.362-5.954, p = 0.000), and glycated hemoglobin (HbA1C) (OR = 1.325, 95% CI: 1.221-1.438, p = 0.000) were independent risk factors for T2DM patients with VTDR. A nomogram was constructed using these variables. The model discrimination results showed an AUC of 0.7193 for the training set and 0.6897 for the testing set. The Hosmer-Lemeshow test results showed a high consistency between the predicted and observed probabilities for both the training set (Chi-square=2.2029, P=0.9742) and the testing set (Chi-square=7.6628, P=0.4671).

Conclusion

The introduction of Age, BMI, SBP, Duration, and HbA1C as variables helps to stratify the risk of T2DM patients with VTDR.

The Ratio of Fibrinogen to Albumin is Related to the Occurrence of Retinopathy in Type 2 Diabetic Patients

Purpose

Type 2 diabetic retinopathy is a long-term chronic inflammatory disease. The aim of this study was to investigate the relationship between fibrinogen to albumin ratio (FAR) and retinopathy in type 2 diabetic patients.

Methods

This was a retrospective study that included 500 patients with type 2 diabetes mellitus (T2DM), and were divided into non-diabetic retinopathy group (NDR, n=297) and diabetic retinopathy group (DR, n=203) according to fundus examination findings, and the DR group was further divided into non-proliferative retinopathy group (NPDR, n=182) and proliferative retinopathy group (PDR, n=21). Baseline data of patients were collected, and the fibrinogen to albumin ratio (FAR) and neutrophil to lymphocyte ratio (NLR) were calculated to analyze the correlation between FAR and NLR and type 2 diabetic retinopathy.

Results

The FAR and NLR were significantly higher in the DR group compared with the NDR group (both P < 0.001). Spearman correlation analysis showed that FAR was positively correlated with NLR and DR (P < 0.05). As the FAR quartile increased, the prevalence of DR increased (14.8%, 16.7%, 25.1%, and 43.30%, respectively; P < 0.05). Multifactorial logistic regression analysis showed that FAR, diabetic course, systolic blood pressure (SBP) and diabetic peripheral neuropathy (DPN) were risk factors for the development of DR in patients with T2DM. The area under the ROC curve for FAR to predict DR progression was 0.708, with an optimal critical value of 7.04, and the area under the ROC curve for diabetes duration and SBP to predict DR was 0.705 and 0.588, respectively.

Conclusion

Our findings show for the first time that FAR is an independent risk factor for assessing DR in patients with type 2 diabetes.

Artificial intelligence in ophthalmology: The path to the real-world clinic

Artificial intelligence (AI) has great potential to transform healthcare by enhancing the workflow and productivity of clinicians, enabling existing staff to serve more patients, improving patient outcomes, and reducing health disparities. In the field of ophthalmology, AI systems have shown performance comparable with or even better than experienced ophthalmologists in tasks such as diabetic retinopathy detection and grading. However, despite these quite good results, very few AI systems have been deployed in real-world clinical settings, challenging the true value of these systems. This review provides an overview of the current main AI applications in ophthalmology, describes the challenges that need to be overcome prior to clinical implementation of the AI systems, and discusses the strategies that may pave the way to the clinical translation of these systems.

Skin microvascular reactivity in patients with diabetic retinopathy

AIMS

Early detection of microangiopathic complications of diabetes mellitus (DM) is necessary to analyze the patient's condition and prevent disease progression. The study was aimed to investigate the relationship between the presence of retinopathy and decreased reactivity of the microcirculatory bed in patients with diabetes.

METHODS

The study involved 130 subjects: healthy volunteers (n = 48), DM patients without retinopathy (n = 53) and with retinopathy (n = 29). Skin microvascular reactivity was assessed on the forearm using laser Doppler flowmetry with a local heating test combined with occlusion.

RESULTS

The slope of local thermal hyperemia curve (Slope-120) and other parameters of microvascular reactivity showed difference in pairwise comparisons between the groups. Slope-120 had the highest sensitivity (0.759) and specificity (0.717) in detection of diabetic retinopathy. The decrease of Slope-120 was associated with retinopathy (odds ratio (OR) - 8.3 (2.9-24.1), p < 0.001), even after adjusting for other factors (OR - 11.0 (1.6-77.2), p = 0.016).

CONCLUSIONS

Thus, assessment of skin microvascular reactivity may be a useful test for detecting signs of microangiopathic complications and for screening patients in risk group. Decreased microvascular reactivity has been shown to be prospective as an independent indicator of retinopathy in type 1 DM.

Residential greenness exposure and decreased prevalence of diabetic retinopathy: A nationwide analysis in China

OBJECTIVE

Diabetic retinopathy (DR) is a leading cause of vision impairment and blindness among diabetics. We aimed to explore whether long-term exposure to residential greenness was beneficial to DR.

RESEARCH DESIGN AND METHODS

We used data from a large-scale, cross-sectional screening survey conducted in 129 cities of 27 provincial regions of China from 2018 to 2021 among patients with diabetes. We measured residential greenness exposure as the 3-year average of annual maximum Normalized Difference Vegetation Index (NDVI) at a spatial resolution of 250 m. DR was assessed by ophthalmologists based on fundus photographs. The primary outcome was DR, and secondary outcome included DR severity status (i.e., nonproliferative and proliferative), hallmarks of retinal lesions and macular oedema.

RESULTS

A total of 484,380 adult participants with diabetes were included in the current analysis, and 15.7% of them were diagnosed with DR. NDVI was inversely and linearly associated with DR prevalence, and an increment of 0.1 NDVI was associated with a 10% (9%-10%) decrease in DR prevalence. Significant and inverse associations were further found for nonproliferative and proliferative DR, hallmarks of lesions and macular oedema. The association between greenness and DR was stronger among participants who were older, obese, lived in the south, had longer duration of diabetes or did not take antidiabetic medications.

CONCLUSIONS

This large-scale nationwide study provides the first-hand epidemiological evidence on the associations of residential greenness with DR. Our findings highlight the importance of residential greenness in alleviating DR risk especially in an era of aging and urbanization.

The association between retinal microvasculature derived from optical coherence tomography angiography and systemic factors in type 2 diabetics

Aims

To investigate the correlation between the retinal microvasculature using optical coherence tomography angiography (OCTA) and systemic factors in type 2 diabetes mellitus (T2DM) patients.

Methods

This cross-sectional study obtained OCTA data from patients with T2DM administered at hospital and referred to ophthalmic services. Patient data about demographics, comorbid conditions, and blood biomarkers were extracted from electronic medical records. Data from OCTA scans obtained by CIRRUS HD-OCT Model 5,000 were obtained. Vessel density (VD) and perfusion density (PD) within the superficial capillary plexus, and foveal avascular zone (FAZ) area were automatically segmented. These parameters were tested for their correlations with systemic factors by univariate and multivariable linear regression analyses.

Results

A total of 144 T2DM patients (236 eyes) were available for analysis, with mean age of 53.6 (SD = 10.34) and 56.9% were male. Chronic kidney disease, cardiovascular disease, increased serum creatinine (Scr), red blood cell count (RBC), platelets (PLT), apolipoprotein B (APOB), and decreased urine albumin to creatinine ratio (UACR) were significantly associated with lower VD and PD (all p &lt; 0.013). UACR and triglyceride (TRIG) were significantly correlated with FAZ area (all p &lt; 0.017). In multivariate analyses, PLT, eGFR, and APOB were independent risk factors for retinal rarefaction, and UACR was a significant predictor of FAZ area.

Conclusion

We found several systemic risk factors, such as PLT, renal function and lipid profiles were associated with PD, VD, and FAZ area among Chinese T2DM patients.

Using Data to Improve the Management of Diabetes: The Tayside Experience

Tayside is a region in the East of Scotland and forms one of nine local government regions in the country. It is home to approximately 416,000 individuals who fall under the National Health Service (NHS) Tayside health board, which provides health care services to the population. In Tayside, Scotland, a comprehensive informatics network for diabetes care and research has been established for over 25 years. This has expanded more recently to a comprehensive Scotland-wide clinical care system, Scottish Care Information - Diabetes (SCI-Diabetes). This has enabled improved diabetes screening and integrated management of diabetic retinopathy, neuropathy, nephropathy, cardiovascular health, and other comorbidities. The regional health informatics network links all of these specialized services with comprehensive laboratory testing, prescribing records, general practitioner records, and hospitalization records. Not only do patients benefit from the seamless interconnectedness of these data, but also the Tayside bioresource has enabled considerable research opportunities and the creation of biobanks. In this article we describe how health informatics has been used to improve care of people with diabetes in Tayside and Scotland and, through anonymized data linkage, our understanding of the phenotypic and genotypic etiology of diabetes and associated complications and comorbidities.

DeepDRiD: Diabetic Retinopathy-Grading and Image Quality Estimation Challenge

We described a challenge named "Diabetic Retinopathy (DR)-Grading and Image Quality Estimation Challenge" in conjunction with ISBI 2020 to hold three sub-challenges and develop deep learning models for DR image assessment and grading. The scientific community responded positively to the challenge, with 34 submissions from 574 registrations. In the challenge, we provided the DeepDRiD dataset containing 2,000 regular DR images (500 patients) and 256 ultra-widefield images (128 patients), both having DR quality and grading annotations. We discussed details of the top 3 algorithms in each sub-challenges. The weighted kappa for DR grading ranged from 0.93 to 0.82, and the accuracy for image quality evaluation ranged from 0.70 to 0.65. The results showed that image quality assessment can be used as a further target for exploration. We also have released the DeepDRiD dataset on GitHub to help develop automatic systems and improve human judgment in DR screening and diagnosis.

Nomogram for Prediction of Diabetic Retinopathy Among Type 2 Diabetes Population in Xinjiang, China

PURPOSE

To establish an accurate risk prediction model of diabetic retinopathy (DR) using cost effective and easily available patients' characteristics and clinical biomarkers.

PATIENTS AND METHODS

Totally 18,904 cases diagnosed type 2 diabetes mellitus (T2DM) were collected, among which 13,980 cases were selected after quality screening. The least absolute shrinkage and selection operator (LASSO) regression models were used for univariate analysis and factors selection, and the multi-factor logistic regression analysis was used to establish the prediction model. Discrimination, calibration, and clinical usefulness of the prediction model were assessed using AUC/ Harrell's C statistic, calibration plot, and decision curve analysis. Both the development group and validation group were assessed.

RESULTS

Candidate variables were selected by Lasso regression and multivariate logistic regression analysis. Finally, the candidate predictive variables were included diabetic peripheral neuropathy (DPN), age, neutrophilic granulocyte (NE), high-density lipoprotein (HDL), hemoglobin A1c (HbA1C), duration of T2DM, and glycosylated serum protein (GSP) were used to establish a nomogram model for predicting the risk of DR. In the development group, the area under the receiver operating characteristic curve (AUC) was 0.882 (95% CI, 0.875-0.888). In the validation group, the AUC was 0.870 (95% CI, 0.856-0.881). Meanwhile, the optimism-corrected Harrell's C statistic were 0.878 and 0.867 in the development group and the validation group, respectively. Decision curve analysis demonstrated that the nomogram was clinically useful.

CONCLUSION

We constructed and verified nomograms that could accurately predict the risk of DR in T2DM patients, which could be used to predict the personalized risk of DR patients in Xinjiang, China.

A deep learning system for detecting diabetic retinopathy across the disease spectrum

Retinal screening contributes to early detection of diabetic retinopathy and timely treatment. To facilitate the screening process, we develop a deep learning system, named DeepDR, that can detect early-to-late stages of diabetic retinopathy. DeepDR is trained for real-time image quality assessment, lesion detection and grading using 466,247 fundus images from 121,342 patients with diabetes. Evaluation is performed on a local dataset with 200,136 fundus images from 52,004 patients and three external datasets with a total of 209,322 images. The area under the receiver operating characteristic curves for detecting microaneurysms, cotton-wool spots, hard exudates and hemorrhages are 0.901, 0.941, 0.954 and 0.967, respectively. The grading of diabetic retinopathy as mild, moderate, severe and proliferative achieves area under the curves of 0.943, 0.955, 0.960 and 0.972, respectively. In external validations, the area under the curves for grading range from 0.916 to 0.970, which further supports the system is efficient for diabetic retinopathy grading.

Association between Systolic Blood Pressure and Diabetic Retinopathy in Both Hypertensive and Normotensive Patients with Type 2 Diabetes: Risk Factors and Healthcare Implications

A common diabetes-related microvascular complication is diabetic retinopathy (DR), yet associations between blood pressure (BP) and risks for DR in diabetic patients with normal BP received inadequate attention. This may lead to 'clinical inertia' in early DR prevention. We aimed to assess whether the extent to which systolic BP levels were associated with DR in patients with type 2 diabetes (T2DM) and normal BP were similar to that in those with concurrent hypertension. Data were collected from patients with T2DM attending ophthalmic check-up with primary care referral (n = 2510). BP measurements, clinical laboratory tests, and dilated fundus examination were conducted according to gold standard of diagnosis and routine clinical procedure. Of all subjects, over 40% were normotensive and one fifth were clinically diagnosed with DR. Systolic BP levels increased across DR categories of escalated severity irrespective of the coexistence of hypertension. Ordinal logistic regression analysis showed that an increased systolic BP was independently and significantly associated with DR (adjusted odds ratio [aOR] = 1.020, p < 0.001 for hypertensives; aOR = 1.019, p = 0.018 for normotensives), after adjusting for diabetes duration, sex, lifestyles, and haemoglobin A1c levels. Regular monitoring of systolic BP should not be neglected in routine diabetes management even when BP falls within the normal range. (200 words).

Microvascular disease and heart failure with reduced and preserved ejection fraction in type 2 diabetes

Aims

Identification of patients with type 2 diabetes (T2D) at increased risk of incident heart failure (HF) beyond traditional risk factors such as prior myocardial infarction (MI) might allow selection of patients who would benefit from preventative treatment. Microvascular disease (MiVD) is thought to play a pathophysiological role in the development of HF in T2D; however, its association with new‐onset HF with reduced or preserved ejection fraction has not been specifically defined.

Methods and results

Patients in the Genetics of Diabetes Audit and Research Tayside Scotland study were linked to echocardiography, prescriptions, and clinical outcomes. In total, 9141 patients with T2D were identified for analysis. Clinical variables and the presence of retinopathy, nephropathy, and neuropathy were assessed. Cumulative incidence was calculated for the association of both individual and the total number of MiVD states and incident HF. Median follow‐up was 9.3 years. In total, there were 900 HF events. The presence of any MiVD was independently associated with both HF with reduced ejection fraction (hazard ratio 1.40; 95% confidence interval 1.11–1.76, P = 0.004) and HF with preserved ejection fraction (hazard ratio 1.38; 95% confidence interval 1.10–1.72, P = 0.005), with a stepwise association between the number of MiVD states and risk of incident HF (P for trend <0.001). Similar associations were found in sensitivity analyses limited to patients without a prior MI, and using competing risks analysis.

Conclusions

Individuals with T2D and with MiVD are at risk of incident HF independent of a history of prior HF or MI. Patients with MiVD could benefit from screening for HF and individualized therapy with treatments that lower HF risk.

Clinical Predictors of Diabetic Retinopathy Progression; A Systematic Review

OBJECTIVE

This study was conducted to discuss the clinical value of published Diabetic Retinopathy Progression determinants.

METHODS

The data for systematic review was collected from the published studies through PubMed and Medline. These studies discussed the clinical predictors of Diabetic Retinopathy (DR) progression. The common keywords used were diabetic Retinopathy, diabetes mellitus, systolic blood pressure, hemoglobin, and albuminuria.

RESULTS

Diabetic Retinopathy is one of the common causes of irreversible visual impairment among adults. Poor glycemic control, systemic hypertension, diabetes duration, dyslipidemia, and microalbuminuria are the major risk factors for the development and progression of diabetic retinopathy. Recently, increased aortic stiffness has been identified as a prognostic marker of diabetic retinopathy and peripheral neuropathy.

CONCLUSION

Certain groups of diabetic individuals are at higher risk to have progressive diabetic retinopathy and eventually visual impairment. Clinical determinants and predictors are considered as prognostic markers and could help physicians to develop an effective risk-based screening program for this condition.

Effects of sodium-glucose cotransporter-2 inhibitors and dipeptidyl peptidase-4 inhibitors on diabetic retinopathy and its progression: A real-world Korean study

The sodium-glucose cotransporter-2 inhibitors (SGLT2is) reduce the incidence of macrovascular complications of diabetes, while their effect on diabetic retinopathy has not been clarified. We compared the effects of SGLT2is with those of dipeptidyl peptidase-4 inhibitors (DPP4is) on the risk of diabetic retinopathy and its progression in people with type 2 diabetes. We performed a retrospective cohort study among people with type 2 diabetes who started on a SGLT2i or DPP4i from 2014 to 2016 according to the Korean National Health Insurance Service database. Subjects initiated on a SGLT2i or DPP4i were matched on a 1:1 basis according to their propensity scores, and Cox proportional hazards regression models were used to calculate the hazard ratios for the risk of diabetic retinopathy and its progression. After propensity score-matching, 41,430 patients without a history of diabetic retinopathy were identified as new users of a SGLT2i (n = 20,175) or DPP4i (n = 20,175). The hazard ratio (95% CI) for diabetic retinopathy was 0.89 (0.83–0.97) for SGLT2i initiators compared with DPP4i initiators. In patients with a history of diabetic retinopathy (n = 4,663 pairs), there was no significant difference in diabetic retinopathy progression between SGLT2i initiators and DPP4i initiators (hazard ratio 0.94, 95% CI 0.78–1.13). This real-world cohort study showed that SGLT2is might be associated with lower risk of diabetic retinopathy compared with DPP4is. Randomized controlled trials are needed to investigate the long-term effect of SGLT2is in diabetic retinopathy in people with diabetes.

Incidence of sight-threatening diabetic retinopathy in people with Type 2 diabetes mellitus and numbers needed to screen: a systematic review

AIM

To investigate the incidence of sight-threatening diabetic retinopathy in Type 2 diabetes mellitus.

BACKGROUND

In most countries, yearly or biennial screening intervals for diabetic retinopathy in people with Type 2 diabetes are recommended. Fewer screening sessions reduce the effort required of people with Type 2 diabetes and reduce healthcare costs.

METHODS

We conducted a search of PubMed, Embase, Web of Science and the COCHRANE Library for studies published betweeen 1 January 2000 and 1 January 2017. Eligible studies were those that included general populations of >100 people with Type 2 diabetes mellitus. Additional study population criteria were absence of moderate diabetic retinopathy or more severe diabetic retinopathy at last screening session and at least two gradable retinal screening sessions. Outcomes of interest in the included studies were moderate and severe non-proliferative diabetic retinopathy (R2), proliferative diabetic retinopathy (R3) or maculopathy (M1), collectively known as sight-threatening or referable diabetic retinopathy.

RESULTS

A total of 17 studies were included. In people with Type 2 diabetes without or with only mild diabetic retinopathy at baseline, the average incidence rates of sight-threatening diabetic retinopathy were ~1 per 100 person-years and ~8 per 100 person-years, respectively. The average numbers needed to screen to detect one case of sight-threatening diabetic retinopathy were 175 and 19 in people without and with mild retinopathy at last screening, respectively.

CONCLUSION

In people with Type 2 diabetes without retinopathy at last screening, the incidence of severe sight-threatening retinopathy at the subsequent screening session was low. In people with mild retinopathy, progression to sight-threatening diabetic retinopathy was nearly 10-fold higher. This review supports lengthening of the screening interval of patients with Type 2 diabetes without retinopathy at last screening session.

A genome-wide association study implicates that the TTC39C gene is associated with diabetic maculopathy with decreased visual acuity

Background: Diabetic maculopathy is a form of diabetic retinopathy. The visual acuity of one third of patients with diabetic maculopathy will be affected. The purpose of this study was to identify genetic contributors of diabetic maculopathy with decreased visual acuity based on a genome-wide association approach using a well-defined Scottish diabetic cohort. Methods: We used linked e-health records of diabetic patients to define our cases and controls. The cases in this study were defined as type 2 diabetic patients who had ever been recorded in the linked e-health records as having maculopathy (observable or referable) in at least one eye and whose visual acuity of the eye was recorded to have decreased between the first and the last visual acuity record of that eye in the longitudinal e-health records. The controls were defined as a type 2 diabetic individual who had never been diagnosed with maculopathy or retinopathy in the linked e-health records. Anyone who had laser photocoagulation treatment was also excluded from the controls. A standard genome-wide association approach was applied. Results: Overall, we identified 469 cases and 1,374 controls within the Genetics of Diabetes Audit and Research in Tayside Scotland (GoDARTS) dataset. We found that the P value of rs9966620 in the TTC39C gene was 4.13x10^-8, which reached genome-wide significance. Conclusions: We suggest that the TTC39C gene is associated with diabetic maculopathy with decreased visual acuity. This needs to be confirmed by further replication studies and functional studies.

A genome-wide association study suggests new evidence for an association of the NADPH Oxidase 4 (NOX4) gene with severe diabetic retinopathy in type 2 diabetes

Purpose

Diabetic retinopathy is the most common eye complication in patients with diabetes. The purpose of this study is to identify genetic factors contributing to severe diabetic retinopathy.

Methods

A genome‐wide association approach was applied. In the Genetics of Diabetes Audit and Research in Tayside Scotland (GoDARTS) datasets, cases of severe diabetic retinopathy were defined as type 2 diabetic patients who were ever graded as having severe background retinopathy (Level R3) or proliferative retinopathy (Level R4) in at least one eye according to the Scottish Diabetic Retinopathy Grading Scheme or who were once treated by laser photocoagulation. Controls were diabetic individuals whose longitudinal retinopathy screening records were either normal (Level R0) or only with mild background retinopathy (Level R1) in both eyes. Significant Single Nucleotide Polymorphisms (SNPs) were taken forward for meta‐analysis using multiple Caucasian cohorts.

Results

Five hundred and sixty cases of type 2 diabetes with severe diabetic retinopathy and 4,106 controls were identified in the GoDARTS cohort. We revealed that rs3913535 in the NADPH Oxidase 4 (NOX4) gene reached a p value of 4.05 × 10⁻⁹. Two nearby SNPs, rs10765219 and rs11018670 also showed promising p values (p values = 7.41 × 10⁻⁸ and 1.23 × 10⁻⁸, respectively). In the meta‐analysis using multiple Caucasian cohorts (excluding GoDARTS), rs10765219 and rs11018670 showed associations for diabetic retinopathy (p = 0.003 and 0.007, respectively), while the p value of rs3913535 was not significant (p = 0.429).

Conclusion

This genome‐wide association study of severe diabetic retinopathy suggests new evidence for the involvement of the NOX4 gene.

Incidence of diabetic eye disease among migrants: A cohort study of 100,000 adults with diabetes in Denmark

AIMS

To examine the incidence rates of any and referable diabetic retinopathy (DR) among migrants in Denmark.

METHODS

Nationwide clinical data on diabetes patients followed since 2005 were analysed. Patients were classified according to country of origin into six groups: Denmark, other Europe, Sub Saharan Africa, Middle East/North Africa, Asia, and America/Oceania. A total of 93,780 or 110,897 patients without any (including unspecific diagnoses) or referable (proliferative) DR at baseline were analyzed. We estimated event rates and hazard ratios (HRs) for incidence of any and referable DR according to country of origin.

RESULTS

After an average follow-up of 3.59 years 6727 had incident any DR and 4747 patients had referable DR. Compared to people of Danish origin, migrants from the Middle East/North Africa and Asia had a higher risk of any and referable DR after adjustment for age, sex, body mass index, smoking status, types and duration of diabetes, clinic type (general practice vs outpatient clinic), HbA1c, blood pressure and lipid levels. The associations remained significant after further adjustment for frequency of eye screening.

CONCLUSIONS

Migrants from the Middle East/North Africa and Asia were at increased risk of developing any and referable DR compared to native Danes, and these differences were not fully explained by differences in underlying clinical, diabetic and cardiometabolic risk factors.

Lp-PLA2 activity is associated with increased risk of diabetic retinopathy: a longitudinal disease progression study

AIMS/HYPOTHESIS

The aim of the study was to examine the association between lipoprotein-associated phospholipase A2 (Lp-PLA2) activity levels and incident diabetic retinopathy and change in retinopathy grade.

METHODS

This was a cohort study of diabetic participants with serum collected at baseline and routinely collected diabetic retinal screening data. Participants with type 2 diabetes from the GoDARTS (Genetics of Diabetes Audit and Research in Tayside Scotland) cohort were used. This cohort is composed of individuals of white Scottish ancestry from the Tayside region of Scotland. Survival analysis accounting for informative censoring by modelling death as a competing risk was performed for the development of incident diabetic retinopathy from a disease-free state in a 3 year follow-up period (n = 1364) by stratified Lp-PLA2 activity levels (in quartiles). The same analysis was performed for transitions to more severe grades.

RESULTS

The hazard of developing incident diabetic retinopathy was 2.08 times higher (95% CI 1.64, 2.63) for the highest quartile of Lp-PLA2 activity compared with the lowest. Higher Lp-PLA2 activity levels were associated with a significantly increased risk for transitions to all grades. The hazards of developing observable (or more severe) and referable (or more severe) retinopathy were 2.82 (95% CI 1.71, 4.65) and 1.87 (95% CI 1.26, 2.77) times higher for the highest quartile of Lp-PLA2 activity compared with the lowest, respectively.

CONCLUSIONS/INTERPRETATION

Higher Lp-PLA2 levels are associated with increased risk of death and the development of incident diabetic retinopathy, as well as transitions to more severe grades of diabetic retinopathy. These associations are independent of calculated LDL-cholesterol and other traditional risk factors. Further, this biomarker study shows that the association is temporally sensitive to the proximity of the event to measurement of Lp-PLA2.

Serum Extracellular Superoxide Dismutase Is Associated with Diabetic Retinopathy Stage in Chinese Patients with Type 2 Diabetes Mellitus

Extracellular superoxide dismutase (ecSOD) is the major extracellular scavenger of reactive oxygen species and associated with the diabetic complication in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the serum ecSOD activity in Chinese patients with different stages of diabetic retinopathy (DR) and evaluate the association between the serum ecSOD activity and the severity of DR. A total of 343 T2DM patients were categorized into three groups: nondiabetic retinopathy (NDR) group, nonproliferative diabetic retinopathy (NPDR) group, and proliferative diabetic retinopathy (PDR) group. Serum ecSOD activities were measured by the autoxidation of the pyrogallol method. In this study, 271, 46, and 26 patients were enrolled in the NDR, NPDR, and PDR groups, respectively. We found a significantly decreased trend of serum ecSOD activity among NDR subjects (118.0 ± 11.5 U/mL) compared to NPDR subjects (108.5 ± 11.9 U/mL) (P < 0.001) and NPDR subjects compared to PDR subjects (102.7 ± 12.4 U/mL) (P = 0.041). Serum ecSOD activity was an independent risk factor for DR (OR = 0.920, P < 0.001) and was associated with the progression of DR. Serum ecSOD activity might be a biomarker for DR screening and evaluation of the clinical severity of DR in Chinese T2DM patients.

Optimal screening schedules for disease progression with application to diabetic retinopathy

Clinical management of chronic diseases requires periodic evaluations. Subjects transition between various levels of severity of a disease over time, one of which may trigger an intervention that requires treatment. For example, in diabetic retinopathy, patients with type 1 diabetes are evaluated yearly for either the onset of proliferative diabetic retinopathy (PDR) or clinically significant macular edema (CSME) that would require immediate treatment to preserve vision. Herein, we investigate methods for the selection of personalized cost-effective screening schedules and compare them with a fixed visit schedule (e.g., annually) in terms of both cost and performance. The approach is illustrated using the progression of retinopathy in the DCCT/EDIC study.

A Diabetic Retinopathy Screening Tool for Low-Income Adults in Mexico

INTRODUCTION

A national diabetic retinopathy screening program does not exist in Mexico as of 2017. Our objective was to develop a screening tool based on a predictive model for early detection of diabetic retinopathy in a low-income population.

METHODS

We analyzed biochemical, clinical, anthropometric, and sociodemographic information from 1,000 adults with diabetes in low-income communities in Mexico (from 11,468 adults recruited in 2014-2016). A comprehensive ophthalmologic evaluation was performed. We developed the screening tool through the following stages: 1) development of a theoretical predictive model, 2) performance assessment and validation of the model using cross-validation and the area under the receiver operating characteristic curve (AUC ROC), and 3) optimization of cut points for the classification of diabetic retinopathy. We identified points along the AUC ROC that minimized the misclassification cost function and considered various scenarios of misclassification costs and diabetic retinopathy prevalence.

RESULTS

Time since diabetes diagnosis, high blood glucose levels, systolic hypertension, and physical inactivity were considered risk factors in our screening tool. The mean AUC ROC of our model was 0.780 (validation data set). The optimized cut point that best represented our study population (z = -0.640) had a sensitivity of 82.9% and a specificity of 61.9%.

CONCLUSION

We developed a low-cost and easy-to-apply screening tool to detect people at high risk of diabetic retinopathy in Mexico. Although classification performance of our tool was acceptable (AUC ROC > 0.75), error rates (precision) depend on false-negative and false-positive rates. Therefore, confirmatory assessment of all cases is mandatory.

Hypertension with diabetes mellitus: significance from an epidemiological perspective for Japanese

The prevalence of both hypertension and diabetes mellitus is increasing worldwide. Both diseases lead to severe complications such as cardiovascular and chronic kidney diseases, which increase the risk of death over a long period of time. Therefore, the prevention and aggravation of hypertension and diabetes mellitus are major challenges. Because few review articles have focused on the epidemiological perspective of hypertension and diabetes mellitus, we reviewed major observational studies mainly from Japan and from Western countries that have reported on the prevalence of hypertension and diabetes mellitus, the binominal risk of hypertension and diabetes mellitus, and the risk of their coexistence. Our investigation found that approximately 50% of diabetic patients had hypertension, and approximately 20% of hypertensive patients had diabetes mellitus. Those with either hypertension or diabetes mellitus had a 1.5- to 2.0-fold higher risk of having both conditions. These results were similar for both Japan and Western countries. Although comparing the results between Japan and Western countries was difficult because the risks were estimated using widely varying statistical analyses, it was revealed that the coexistence of hypertension and diabetes mellitus certainly increased the risk of complications regardless of the country. The definition, prevalence and medical treatment of hypertension and diabetes mellitus will change in the future. For early intervention based on the latest evidence to prevent severe complications, it is important to accumulate epidemiological knowledge of hypertension and diabetes mellitus and to update the evidence for both Japan and other countries.

Predictors of Development and Progression of Retinopathy in Patients with Type 2 Diabetes: Importance of Blood Pressure Parameters

Diabetic retinopathy (DR) is a chronic microvascular complication associated a worse prognosis. We aimed to evaluate the predictors of development/progression of DR in a cohort of 544 high-risk patients with type 2 diabetes who had annual ophthalmologic examinations over a median follow-up of 6 years. Ambulatory blood pressure (BP) monitoring and aortic stiffness by carotid-femoral pulse wave velocity were performed. Multivariate Cox survival analysis examined the independent predictors of development or progression of DR. During follow-up, 156 patients either newly-developed or worsened DR. Patients who developed/progressed DR had longer diabetes duration, higher ambulatory and clinic BP levels, higher aortic stiffness, and poorer glycemic control than patients who did not developed/progressed DR. After adjustments for baseline retinopathy prevalence, age and sex, a longer diabetes duration (p < 0.001), higher baseline ambulatory BPs (p = 0.013, for 24-hour diastolic BP), and higher mean cumulative exposure of HbA_1c (p < 0.001), clinic diastolic BP (p < 0.001) and LDL-cholesterol (p = 0.05) during follow-up were the independent predictors of development/progression of DR. BP parameters were only predictors of DR development. In conclusion, a longer diabetes duration, poorer glycemic and lipid control, and higher BPs were the main predictors of development/progression of DR. Mean cumulative clinic diastolic BP was the strongest BP-related predictor.

PROTECTIVE EFFECTS OF DIPEPTIDYL PEPTIDASE-4 INHIBITORS ON PROGRESSION OF DIABETIC RETINOPATHY IN PATIENTS WITH TYPE 2 DIABETES

PURPOSE

To investigate the effects of dipeptidyl peptidase-4 (DPP4) inhibitors on the progression of diabetic retinopathy (DR) in patients with Type 2 diabetes based on the DR severity scale.

METHODS

The medical records of 82 patients with Type 2 diabetes enrolled from 2005 to 2015 were retrospectively reviewed. Fundus photographs were graded using Early Treatment Diabetic Retinopathy Study methods. The associations between baseline risk factors and progression of DR were investigated.

RESULTS

Seven of 28 patients treated with DPP4 inhibitors and 26 of 54 treated with other hypoglycemic agents showed progression of retinopathy, defined as one or more steps on the Early Treatment Diabetic Retinopathy Study scale (P = 0.043). Only treatment with DPP4 inhibitors significantly reduced the progression of DR in patients after propensity score matching (P = 0.009). Treatment with DPP4 inhibitors was associated with a lower risk of DR progression (P = 0.011).

CONCLUSION

Treatment with DPP4 inhibitors was the independent protective factor against the progression of DR, aside from improving glycemic control. This is the first study to show the benefits of DPP4 inhibitors in reducing DR progression, and provides encouraging preliminary data for further evaluation of DPP4 inhibitors in the progression of DR in a randomized, double-blind, placebo-controlled trial.

Frequency of Evidence-Based Screening for Retinopathy in Type 1 Diabetes

BACKGROUND

In patients who have had type 1 diabetes for 5 years, current recommendations regarding screening for diabetic retinopathy include annual dilated retinal examinations to detect proliferative retinopathy or clinically significant macular edema, both of which require timely intervention to preserve vision. During 30 years of the Diabetes Control and Complications Trial (DCCT) and its longitudinal follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study, retinal photography was performed at intervals of 6 months to 4 years.

METHODS

We used retinal photographs from the DCCT/EDIC study to develop a rational screening frequency for retinopathy. Markov modeling was used to determine the likelihood of progression to proliferative diabetic retinopathy or clinically significant macular edema in patients with various initial retinopathy levels (no retinopathy or mild, moderate, or severe nonproliferative diabetic retinopathy). The models included recognized risk factors for progression of retinopathy.

RESULTS

Overall, the probability of progression to proliferative diabetic retinopathy or clinically significant macular edema was limited to approximately 5% between retinal screening examinations at 4 years among patients who had no retinopathy, 3 years among those with mild retinopathy, 6 months among those with moderate retinopathy, and 3 months among those with severe nonproliferative diabetic retinopathy. The risk of progression was also closely related to mean glycated hemoglobin levels. The risk of progression from no retinopathy to proliferative diabetic retinopathy or clinically significant macular edema was 1.0% over 5 years among patients with a glycated hemoglobin level of 6%, as compared with 4.3% over 3 years among patients with a glycated hemoglobin level of 10%. Over a 20-year period, the frequency of eye examinations was 58% lower with our practical, evidence-based schedule than with routine annual examinations, which resulted in substantial cost savings.

CONCLUSIONS

Our model for establishing an individualized schedule for retinopathy screening on the basis of the patient's current state of retinopathy and glycated hemoglobin level reduced the frequency of eye examinations without delaying the diagnosis of clinically significant disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; DCCT/EDIC ClinicalTrials.gov numbers, NCT00360893 and NCT00360815 .).

Evaluation of the association between diabetic retinopathy and the incidence of atrial fibrillation: A nationwide population-based study

BACKGROUND

Atrial fibrillation (AF) is prevalent among type 2 diabetic patients. However, the association between diabetic retinopathy (DR) and AF is controversial.

METHODS

We included 40,500 patients with type 2 diabetes (≥40years, mean age 62±11years, 53% men) without AF from the Korean National Insurance Service-National Sample Cohort (2002-2007). Subjects were classified without DR (non-DR, n=30,178), with DR (DR, n=8920), and with proliferative DR (PDR, n=1402).

RESULTS

During a mean 5.9-year follow-up, 1261 (3.1%) patients were newly diagnosed as having AF (4.9, 6.0, and 8.3 per 1000 person-years in the non-DR, DR, and PDR groups, respectively). In multivariate Cox proportional hazard models, patients in the DR and PDR groups had a significantly higher risk of AF than those in the non-DR group (DR group: hazard ratio [HR] 1.14, 95% confidence interval [CI] 1.00-1.30; PDR group: HR 1.46, 95% CI 1.13-1.87); p for trend <0.001). The risk of AF increased in patients with DR and end-stage renal disease (ESRD) (HR 2.39, 95% CI 1.31-3.96, p<0.001) and in those with PDR and ESRD (HR 3.59, 95% CI 1.96-5.97, p<0.001) compared to those without DR and ESRD.

CONCLUSIONS

The presence and severity of DR was significantly associated with the incidence of AF. Also, the presence of ESRD had an impact on the incidence of AF in patients with DR.

Clinical biomarkers and molecular basis for optimized treatment of diabetic retinopathy: current status and future prospects

Diabetic retinopathy is a highly specific microvascular complication of diabetes and a leading cause of blindness worldwide. It is triggered by hyperglycemia which causes increased oxidative stress leading to an adaptive inflammatory assault to the neuroretinal tissue and microvasculature. Prolonged hyperglycemia causes increased polyol pathway flux, increased formation of advanced glycation end-products, abnormal activation of signaling cascades such as activation of protein kinase C (PKC) pathway, increased hexosamine pathway flux, and peripheral nerve damage. All these changes lead to increased oxidative stress and inflammatory assault to the retina resulting in structural and functional changes. In addition, neuroretinal alterations affect diabetes progression. The most effective way to manage diabetic retinopathy is by primary prevention such as hyperglycemia control. While the current mainstay for the management of severe and proliferative diabetic retinopathy is laser photocoagulation, its role is diminishing with the development of newer drugs including corticosteroids, antioxidants, and antiangiogenic and anti-VEGF agents which work as an adjunct to laser therapy or independently. The current pharmacotherapy of diabetic retinopathy is incomplete as a sole treatment option in view of limited efficacy and short-term effect. There is a definite clinical need to develop new pharmacological therapies for diabetic retinopathy, particularly ones which would be effective through the oral route and help recover lost vision. The increasing understanding of the mechanisms of diabetic retinopathy and its biomarkers is likely to help generate better and more effective medications.

African Ancestry Analysis and Admixture Genetic Mapping for Proliferative Diabetic Retinopathy in African Americans

PURPOSE

To examine the relationship between proportion of African ancestry (PAA) and proliferative diabetic retinopathy (PDR) and to identify genetic loci associated with PDR using admixture mapping in African Americans with type 2 diabetes (T2D).

METHODS

Between 1993 and 2013, 1440 participants enrolled in four different studies had fundus photographs graded using the Early Treatment Diabetic Retinopathy Study scale. Cases (n = 305) had PDR while controls (n = 1135) had nonproliferative diabetic retinopathy (DR) or no DR. Covariates included diabetes duration, hemoglobin A1C, systolic blood pressure, income, and education. Genotyping was performed on the Affymetrix platform. The association between PAA and PDR was evaluated using logistic regression. Genome-wide admixture scanning was performed using ANCESTRYMAP software.

RESULTS

In the univariate analysis, PDR was associated with increased PAA (odds ratio [OR] = 1.36, 95% confidence interval [CI] = 1.16-1.59, P = 0.0002). In multivariate regression adjusting for traditional DR risk factors, income and education, the association between PAA and PDR was attenuated and no longer significant (OR = 1.21, 95% CI = 0.59-2.47, P = 0.61). For the admixture analyses, the maximum genome-wide score was 1.44 on chromosome 1.

CONCLUSIONS

In this largest study of PDR in African Americans with T2D to date, an association between PAA and PDR is not present after adjustment for clinical, demographic, and socioeconomic factors. No genome-wide significant locus (defined as having a locus-genome statistic > 5) was identified with admixture analysis. Further analyses with even larger sample sizes are needed to definitively assess if any admixture signal for DR is present.

Effects of vitamin D receptor gene polymorphism and clinical characteristics on risk of diabetic retinopathy in Han Chinese type 2 diabetes patients

PURPOSE

The purpose of this study was to investigate the association of VDR polymorphism with development of retinopathy in a Han Chinese population with type 2 diabetes mellitus.

MATERIALS AND METHODS

A total of 204 T2DM patients were subdivided into groups without diabetic retinopathy (NDR, n=110) and those with DR (n=94). VDR rs2228570 (FokI:C>T), rs1544410 (BsmI:G>A), and rs7975232 (Apal:A>C) polymorphism was assayed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Diabetes duration (10.0 vs. 5.0 years, P<0.01) was longer, systolic blood pressure (143.98 ± 24.31 vs. 135.11 ± 15.23, P<0.01), and HbA1c (9.2 ± 2.06 vs. 8.35 ± 1.62, P<0.01) were higher in DR than in NDR patients. Distribution frequencies of the rs2228570, rs1544410, and rs7975232 genotypes followed the Hardy-Weinberg equilibrium. VDR rs2228570 TT genotype frequency was significantly higher in DR (n=30; 31.9%) than in NDR patients (n=14; 12.7%; P<0.01). DR patients carried more rs2228570 T alleles (n=113; 60.1%) than did NDR patients (n=89; 40.5%; P<0.01). Genotype frequencies of rs1544410 and rs7975232 in NDR and DR patients were not different. Logistic analysis confirmed that diabetes duration (odds ratio (OR) 1.108, P<0.01), SBP (OR 1.022, P<0.05), HbA1c (OR 1.267, P<0.05), and the VDR rs2228570 T allele (OR 1.467, P<0.01) were independently associated with DR risk. TAA haplotype frequency was significantly higher in DR (24.0%) than in NDR (16.1%) patients (P<0.05).

CONCLUSIONS

Diabetes duration, SBP, HbA1c, and the rs2228570 T allele were associated with increased risk of DR. VDR rs2228570 might be good candidate biomarker of DR in Han Chinese T2DM patients.

Association Analysis of Polymorphisms in Genes Related to Oxidative Stress in South Indian Type 2 Diabetic Patients with Retinopathy

BACKGROUND

Diabetic Retinopathy (DR) is one of the most common microvascular complications of type 2 diabetes mellitus (T2DM) and is polygenic with a multitude of genes contributing to disease susceptibility. The present study aimed at exploring the association between DR and seven polymorphisms in oxidative stress-related genes, i.e. ACE, eNOS, p22phox subunit of NAD(P)H oxidase, PARP-1 and XRCC1 in South Indian T2DM subjects.

MATERIALS AND METHODS

The study included 149 T2DM subjects with DR (diagnosed through funduscopic examination) and 162 T2DM patients with no evidence of DR. The selected polymorphisms were genotyped by polymerase chain reaction (PCR) and Taqman allele discrimination assay.

RESULTS

There was no significant difference in the genotype and allele distribution of ACE ins/del, eNOS-786T>C, 894G>T, 4a4b and p22phox 242C>T polymorphisms between T2DM groups with and without DR. Contrastingly, there appeared to be a significant association of PARP-1 Val762Ala and XRCC1 Arg399Gln polymorphisms with DR, wherein 762Ala allele seemed to confer significant protection against DR (p = 0.01; OR = 0.51 [0.3-0.86]), while the presence of 399Gln allele was associated with an enhanced risk for DR (p = 0.02; OR = 1.52 [1.07-2.15]). Multiple logistic regression analysis revealed a significant and independent association of Val762Ala and Arg399Gln polymorphisms and other putative risk factors with DR in T2DM individuals.

CONCLUSIONS

The polymorphisms in the DNA repair genes PARP-1 and XRCC1 tended to associate significantly with DR. While Val762Ala polymorphism was associated with reduced susceptibility to DR, the Arg399Gln polymorphism contributed an elevated to risk for DR in South-Indian T2DM individuals.