Progression to proliferative retinopathy and macular oedema requiring treatment. Assessment of the alternative classification of the Wisconsin Study

Circulating Biomarkers of Inflammation and Endothelial Activation in Diabetic Retinopathy

Inflammation and endothelial activation play a pivotal role in development and progression of diabetic retinopathy (DR), a vision-threatening complication of diabetes mellitus (DM) and the leading cause of blindness in the working age population. Easily accessible and validated biomarkers for DR early diagnosis and progression are required for use in clinical trials: here, we reviewed the available literature to understand the association of circulating levels of selected markers of inflammation and endothelial activation with the presence of nonproliferative and proliferative DR (NPDR and PDR) and investigate the relationship between their systemic and ocular levels. We additionally provide data synthesis and perform statistical analysis for interpretation of the collected evidence. CRP, IL-1β, IL-6, TNFα, sICAM1, and sVCAM1 circulating levels were increased in subjects with DM compared to healthy individuals. Moreover, TNFα and sVCAM1 showed increasing systemic levels with DR presence and severity; circulating CRP increased with the transition from no DR to NPDR, whereas IL-6 was increased in PDR compared to NDPR stages. The relationship between ocular and systemic concentrations of these proteins remained unclear due to the low number of studies with matched sampling. In conclusion, the available data supports the use of systemic biomarkers of inflammation and endothelial activation to identify DM status and DR severity. These systemic biomarkers are likely reflecting an overall state of inflammation and vascular activation in different tissues of the body, including the eyes. Prospective, longitudinal datasets are required to validate these biomarkers as predictors of early DR presence, of DR progression, or for disease monitoring.

Evidence-based Canadian guidelines for tele-retina screening for diabetic retinopathy: recommendations from the Canadian Retina Research Network (CR2N) Tele-Retina Steering Committee

OBJECTIVE

The purpose of this report is to develop a consensus for Canadian national guidelines specific to a tele-medicine approach to screening for diabetic retinopathy (DR) using evidence-based and clinical data.

METHODS

Canadian Tele-Screening Grading Scales for DR and diabetic macular edema (DME) were created primarily based on severity grading scales outlined by the International Clinical Diabetic Retinopathy Disease Severity Scale (ICDR) and the Scottish DR Grading Scheme 2007. Other grading scales used in international screening programs and the clinical expertise of the Canadian Retina Research Network members and retina specialists nationwide were also used in the creation of the guidelines.

RESULTS

National Tele-Screening Guidelines for DR and DME with and without optical coherence tomography (OCT) images are proposed. These outline a diagnosis and management algorithm for patients presenting with different stages of DR and/or DME. General guidelines detailing the requirements for imaged retina fields, image quality, quality control, and follow-up care and the role of visual acuity, pupil dilation, OCT, ultra-wide-field imaging, and artificial intelligence are discussed.

CONCLUSIONS

Tele-retina screening can help to address the need for timely and effective screening for DR, whose prevalence continues to rise. A standardized and evidence-based national approach to DR tele-screening has been proposed, based on DR/DME grading using two 45° image fields or a single widefield or ultra-wide-field image, preferable use of OCT imaging, and a focus on local quality control measures.

Vitreous expression of cytokines and growth factors in patients with diabetic retinopathy-An investigation of their expression based on clinical diabetic retinopathy grade

Diabetic retinopathy (DR) is an inflammatory condition that affects the posterior of the eye; yet, there are limited published data on techniques measuring the expression of growth and inflammatory factors (GIF) from the posterior segment. The purpose of the current study was two-fold: to sample the vitreous fluid from the eyes of patients with DR and assess the expression of GIF. As DR is an inflammatory disease, the second objective of this study was to determine the relationship between the status of DR and the expression of vitreous GIF. This non-randomized clinical trial was approved by BfARM for the analysis and evaluation of 12 eyes from patients with diabetic macular edema. Vitreous sampling was performed before treatment with fluocinolone acetonide and the extracted vitreous material was examined for the determination of GIF including interleukins 6 (IL-6) and 8 (IL-8), interferon gamma-inducible protein (IP-10), monocyte chemoattractant protein-1 (MCP-1), placental growth factor (PIGF), pigment epithelium-derived factor (PEDF), VEGF (vascular endothelial growth factor) and intercellular adhesion molecule (CD54). These were linearly compared with the grade of inflammation in the vitreous assessed via DR score and ART. Additionally, all eyes were grouped based on their diabetic retinopathy status. All cytokine levels, except MCP-1 and PEDF, were numerically higher in DME patients with proliferative DR than those with non-proliferative DR. DR grade was found to linearly correlate with the expression of CD54 (p = 0.02, rho = 0.64), IL-8 (p = 0.03, rho = 0.64) and PIGF (p = 0.007, rho = 0.76). A correlation was found between ART and CD54 (p = 0.02, rho = 0.66) and also between ART and IL-8 (p = 0.04, rho = 0.60). A trend was found between ART and PIGF (p = 0.08, rho 0.52). For IL-6, there appeared to be a trend with DR grade (p = 0.14, rho = 0.45) and ART (p = 0.09, rho = 0.51). Proliferative DR was shown to be associated with a significant higher expression of CD54, IL-8 and PIGF, thus suggesting that they are potentially important in defining and monitoring the effectiveness of a patients' therapy. Vitreous probes may be helpful in deciding which therapy to administer (i.e. anti-VEGF or corticosteroid or both) based on the expression of GIF. Registry EudraCT number: 2016-004488-38; DRKS-ID: DRKS00014915.

Characteristics Associated with Early Worsening of Retinopathy in Patients with Type 2 Diabetes Diagnosed with Retinopathy at Their First Visit: A Retrospective Observational Study

MATERIALS AND METHODS

Our study design was a retrospective observational study. Subjects with type 2 diabetes diagnosed with either simple or preproliferative diabetic retinopathy by ophthalmologists at their first visit and followed up for 6-18 months thereafter were included and divided into worsening and nonworsening groups. Thereafter, baseline characteristics and changes in HbA1c and therapy over a year were investigated.

RESULTS

Among the 88 subjects with simple diabetic retinopathy, 16% improved to no retinopathy, 65% retained their simple diabetic retinopathy, 18% worsened to preproliferative diabetic retinopathy, and 1% worsened to proliferative diabetic retinopathy. Among the 47 subjects with preproliferative diabetic retinopathy, 9% improved to simple diabetic retinopathy, 72% retained their preproliferative diabetic retinopathy, and 19% worsened to proliferative diabetic retinopathy. Patients with simple diabetic retinopathy had an odds ratio of 1.44 for worsening retinopathy with a 1% increase in baseline HbA1c. Meanwhile, the odds ratios for worsening retinopathy with a 1% decrease in HbA1c from baseline at 3, 6, and 12 months were 1.34, 1.31, and 1.38, respectively. Among patients with simple diabetic retinopathy, significantly more new interventions were introduced in the worsening group than in the nonworsening group.

CONCLUSIONS

Increased baseline HbA1c, a substantial decrease in HbA1c, and intensified therapy were identified as risk factors for early worsening of diabetic retinopathy in patients with simple diabetic retinopathy at the first visit. Patients should therefore be intimately followed for retinopathy after their first visit.

Periodontal conditions, retinopathy, and serum markers in individuals with type 1 diabetes

BACKGROUND

The prevalence of diabetes is high and increasing. Periodontitis has been identified as a risk factor in both type 1 and 2 diabetes. The study purpose was to assess periodontal conditions, retinopathy, and serum glutamic acid decarboxylase antibody (GADA) titers in relation to retinopathy in individuals with type 1 diabetes (T1D).

METHODS

The study is a case series. Adult individuals with a diagnosis of T1D (n = 85) monitored ≥5 years were recruited from an endocrinology clinic. Peripheral venous blood samples were analyzed including assessments of serum HbA1c levels and GADA titers. Medical and periodontal conditions were examined, and the data assessed. Independent t tests, binary and multivariate analyses, χ² and odds ratios were employed.

RESULTS

Gingivitis was found in 68.2%, periodontitis in 21.2%, and retinopathy in 64.7%, GADA (≥35 U/mL) in 54.1%, and serum HbA1c > 48 mmol/mol in 94.3% of the individuals. The unadjusted odds ratio for periodontitis to differentiate a diagnosis of retinopathy was 7.3 (95%CI 1.6, 4.4, P <0.01). Multivariate analyses identified the following dependent factors to differentiate retinopathy; age, T1D duration, gingivitis, periodontitis at P < 0.001, sex, and serum GADA at P < 0.01, and by the number of remaining teeth at P < 0.05.

CONCLUSION

Retinopathy as a complication to T1D is linked to the duration of diabetes, age of the individual and with increasing severity to periodontitis. Periodontal intervention studies are warranted.

HbA1c levels in children with type 1 diabetes and correlation to diabetic retinopathy

BACKGROUND

Type 1 diabetes mellitus (T1D) is a metabolic disease causing hyperglycemia due to β-cell destruction. Despite adequate treatment, complications such as diabetic retinopathy (DR) are common. The first aim was to investigate if acute onset of type 1 diabetes differed between those who had developed retinopathy and who had not after 15 years from diagnosis. The second aim was to investigate if mean glycosylated hemoglobin (HbA1c) levels affect the time to development of DR.

METHODS

The medical records of all children and adolescents diagnosed with type 1 diabetes during 1993-2001 in our area in Sweden were studied retrospectively and the mean HbA1c each year until the development of retinopathy was investigated. In total 72 patients were included and the follow-up time was between 15 and 23 years. Gender, p-glucose, age and HbA1c at diagnosis were analyzed for possible correlations to years to retinopathy.

RESULTS

HbA1c was significantly higher among those who had developed DR after 15 years from diagnosis, 98±9.2 (n=25) vs. 86±9.2 (n=46; p=0.025). A negative correlation was found between age at diagnosis and years to DR (rs=-0.376; p=0.026). Mean HbA1c levels at years 6-10 after diabetes diagnosis correlated significantly (rs=-0.354, p=0.037) to years until retinopathy. Mean HbA1c levels at years 1-15 after diabetes diagnosis were significantly higher at years 2-3 and years 5-8 for those who had developed retinopathy after 15 years from diagnosis.

CONCLUSIONS

Higher HbA1c levels shortened the time to development of retinopathy. It is therefore important to keep HbA1c as close to normal as possible.

Experience of intravitreal triamcinolone acetonide for treatment of diabetic macular edema among Omani population

PURPOSE:

The purpose of this study was to evaluate the outcome of intravitreal (IVT) triamcinolone in diabetic macular edema (DME).

MATERIALS AND METHODS:

A retrospective study of 42 eyes diagnosed clinically and supported with optical coherence tomography (OCT), with DME of more than 300 μm in thickness. All eyes were injected with a single IVT injection of preservative free triamcinolone acetonide (TA) with dose of 4 mg. Patients were subjected to visual acuity (VA) and OCT on each follow-up visit which was continued for 6 months. The total number of IVT injections given was 48. Six eyes had a repeat injection. None of the eyes had any other IVT injection within 6 weeks of TA. Twenty-one eyes were pseudophakic.

RESULTS:

Mean age of the patients was 58.8 years. The mean central subfield thickness (CST) at baseline was 504.6 μm. At 6 weeks, the mean CST dropped by 183.6 μm (P < 0.00001). At 6-month follow-up, the mean CST had increased by 74.6 μm from 6 weeks level; however, the 6-month mean CST was 109 μ less than mean baseline thickness (P < 0.0005). The mean baseline VA was 0.80 LogMAR units. At 6 weeks, the mean VA dropped by 0.01 LogMAR. At 6 months, VA improved by 0.02 LogMAR units from baseline. Overall, VA improved in 47% eyes, dropped from baseline in 35% eyes, and remained unchanged in 18% eyes.

CONCLUSION:

Triamcinolone acetonide is a safe, effective, and promising therapy in DME.

Cost-utility of ranibizumab versus aflibercept for treating Greek patients with visual impairment due to diabetic macular edema

Background

To conduct a cost-utility analysis of ranibizumab versus aflibercept for the treatment of patients with visual impairment due to diabetic macular edema (DME) in the Greek setting.

Methods

A Markov model was adapted to compare the use of ranibizumab 0.5 mg (pro re nata-PRN and treat and extend-T&E) to aflibercept 2 mg (every 8 weeks after five initial doses) in DME. Patients transitioned at a 3-month cycle among nine specified health states (including death) over a lifetime horizon. Transition probabilities, utilities, as well as DME-related mortality were extracted from relevant clinical trials, a network meta-analysis and other published studies. The analysis was conducted from payer perspective and as such only costs reimbursed by the payer were considered (year 2014). The incremental cost per quality-adjusted life year (QALY) gained and the net monetary benefit was the main outcome measures.

Results

Τhe use of PRN and T&E ranibizumab regimens were shown to be cost saving comparing to aflibercept (by €2824 and €22, respectively), and more beneficial in terms of QALYs gained (+0.05) and time without visual impairment (0.031 and 0.034 years), thereby dominating aflibercept. Moreover, ranibizumab used as PRN or T&E resulted in a net monetary benefit of €3984 and €1278, respectively.

Conclusions

Both PRN and T&E ranibizumab regimens were more beneficial and less costly compared to aflibercept for the management of DME. Hence, ranibizumab seems to be a dominant option for the treatment of visual impairment due to DME in the Greek setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s12962-016-0056-1) contains supplementary material, which is available to authorized users.

Management paradigms for diabetic macular edema

PURPOSE

To provide evidence-based recommendations for diabetic macular edema (DME) management based on updated information from publications on DME treatment modalities.

DESIGN

Perspective.

METHODS

A literature search for "diabetic macular edema" or "diabetic maculopathy" was performed using the PubMed, Cochrane Library, and ClinicalTrials.gov databases to identify studies from January 1, 1985 to July 31, 2013. Meta-analyses, systematic reviews, and randomized controlled trials with at least 1 year of follow-up published in the past 5 years were preferred sources.

RESULTS

Although laser photocoagulation has been the standard treatment for DME for nearly 3 decades, there is increasing evidence that superior outcomes can be achieved with anti-vascular endothelial growth factor (anti-VEGF) therapy. Data providing the most robust evidence from large phase II and phase III clinical trials for ranibizumab demonstrated visual improvement and favorable safety profile for up to 3 years. Average best-corrected visual acuity change from baseline ranged from 6.1-10.6 Early Treatment Diabetic Retinopathy Study (ETDRS) letters for ranibizumab, compared to 1.4-5.9 ETDRS letters with laser. The proportion of patients gaining ≥ 10 or ≥ 15 letters with ranibizumab was at least 2 times higher than that of patients treated with laser. Patients were also more likely to experience visual loss with laser than with ranibizumab treatment. Ranibizumab was generally well tolerated in all studies. Studies for bevacizumab, aflibercept, and pegaptanib in DME were limited but also in favor of anti-VEGF therapy over laser.

CONCLUSIONS

Anti-VEGF therapy is superior to laser photocoagulation for treatment of moderate to severe visual impairment caused by DME.

Screening intervals for diabetic retinopathy and incidence of visual loss: a systematic review

Screening for diabetic retinopathy can help to prevent this complication, but evidence regarding frequency of screening is uncertain. This paper systematically reviews the published literature on the relationship between screening intervals for diabetic retinopathy and the incidence of visual loss. The PubMed and EMBASE databases were searched until December 2012. Twenty five studies fulfilled the inclusion criteria, as these assessed the incidence/prevalence of sight-threatening diabetic retinopathy in relation to screening frequency. The included studies comprised 15 evaluations of real-world screening programmes, three studies modelling the natural history of diabetic retinopathy and seven cost-effectiveness studies. In evaluations of diabetic retinopathy screening programmes, the appropriate screening interval ranged from one to four years, in people with no retinopathy at baseline. Despite study heterogeneity, the overall tendency observed in these programmes was that 2-year screening intervals among people with no diabetic retinopathy at diagnosis were not associated with high incidence of sight-threatening diabetic retinopathy. The modelling studies (non-economic and economic) assessed a range of screening intervals (1-5 years). The aggregated evidence from both the natural history and cost-effectiveness models favors a screening interval >1 year, but ≤2 years. Such an interval would be appropriate, safe and cost-effective for people with no diabetic retinopathy at diagnosis, while screening intervals ≤1 year would be preferable for people with pre-existing diabetic retinopathy. A 2-year screening interval for people with no sight threatening diabetic retinopathy at diagnosis may be safely adopted. For patients with pre-existing diabetic retinopathy, a shorter interval ≤1 year is warranted.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Plasma kallikrein mediates retinal vascular dysfunction and induces retinal thickening in diabetic rats

OBJECTIVE

Plasma kallikrein (PK) has been identified in vitreous fluid obtained from individuals with diabetic retinopathy and has been implicated in contributing to retinal vascular dysfunction. In this report, we examined the effects of PK on retinal vascular functions and thickness in diabetic rats.

RESEARCH DESIGN AND METHODS

We investigated the effects of a selective PK inhibitor, ASP-440, and C1 inhibitor (C1-INH), the primary physiological inhibitor of PK, on retinal vascular permeability (RVP) and hemodynamics in rats with streptozotocin-induced diabetes. The effect of intravitreal PK injection on retinal thickness was examined by spectral domain optical coherence tomography.

RESULTS

Systemic continuous administration of ASP-440 for 4 weeks initiated at the time of diabetes onset inhibited RVP by 42% (P = 0.013) and 83% (P < 0.001) at doses of 0.25 and 0.6 mg/kg per day, respectively. Administration of ASP-440 initiated 2 weeks after the onset of diabetes ameliorated both RVP and retinal blood flow abnormalities in diabetic rats measured at 4 weeks' diabetes duration. Intravitreal injection of C1-INH similarly decreased impaired RVP in rats with 2 weeks' diabetes duration. Intravitreal injection of PK increased both acute RVP and sustained focal RVP (24 h postinjection) to a greater extent in diabetic rats compared with nondiabetic control rats. Intravitreal injection of PK increased retinal thickness compared with baseline to a greater extent (P = 0.017) in diabetic rats (from 193 ± 10 μm to 223 ± 13 μm) compared with nondiabetic rats (from 182 ± 8 μm to 193 ± 9 μm).

CONCLUSIONS

These results show that PK contributes to retinal vascular dysfunctions in diabetic rats and that the combination of diabetes and intravitreal injection of PK in rats induces retinal thickening.

Multifocal electroretinograms predict onset of diabetic retinopathy in adult patients with diabetes

PURPOSE

The authors' previous models predicted local formation of diabetic retinopathy (DR) in adults with diabetes and existing retinopathy. Here they derived a multivariate model for local prediction of DR onset in patients with no previous retinopathy.

METHODS

Seventy-eight eyes from 41 diabetes patients were tested annually for several years. The presence or absence of DR at the last study visit was the outcome measure, and measurements of risk factors from the previous visit were used for prediction. Logistic regression was used to assess the relationship between DR development and 7 factors: multifocal ERG (mfERG) implicit time (IT) Z-score, sex, diabetes duration, blood glucose, HbA1c, age, and diabetes type. Thirty-five retinal zones, spanning 45°, were constructed from the mfERG stimulus elements. The maximum IT Z-score for each zone was calculated based on data from 50 control subjects. ROC curve analysis, using fivefold cross-validation, was used to determine the model's predictive properties.

RESULTS

Mild DR developed in 80 of 2730 retinal zones (3%) in 29 of 78 eyes (37%). Multivariate analysis showed mfERG IT to be predictive for DR development in a zone after adjusting for diabetes type. The multivariate model has a sensitivity of 80% and a specificity of 74%.

CONCLUSIONS

mfERG IT is a good predictor of DR onset, 1 year later, in patients with diabetes without DR. It can be used to assess the risk for DR development in these patients and may be a valuable outcome measure in evaluation of novel prophylactic therapeutics directed at impeding DR.

Burden of illness of diabetic macular edema: literature review

OBJECTIVE

To provide an overview of the literature on the burden of diabetic macular edema (DME) in the United States and selected European countries.

RESEARCH DESIGN AND METHODS

Computerized searches of English-language literature were conducted in PubMed/MEDLINE (1980-2009). The searches were supplemented with electronic and manual searches of relevant society/association proceedings and bibliographies of electronically identified sources. Abstracts were reviewed for relevance to any of the following topics: epidemiology, including prevalence and incidence; health outcomes; resource use and treatment patterns; and economic and humanistic burden associated with DME. Relevant full text articles were retrieved and major findings were synthesized and compared within and across countries.

RESULTS

A total of 400 citations were included in the initial review. After abstract screening, 47 articles were deemed pertinent and summarized in this review. The prevalence of DME among diabetic patients ranged from 0.85% to 12.3% across the countries studied. The prevalence and incidence of DME vary depending on type of diabetes (1 vs. 2), insulin- vs. non-insulin-dependence, and duration of disease (years since diagnosis). Although literature findings are limited and indicate a need for further investigation, a synthesis of the available results indicates that DME has a negative impact on patients' health-related quality of life. In addition, patients with DME consume significantly more healthcare resources and incur higher costs compared to diabetic patients without retinal complications.

CONCLUSIONS

There remains a need for consistent data capture and assessment within and between countries included in this analysis. Despite the limited evidence, DME appears to be a costly disease that has a negative impact on patients' quality of life.

How the diabetic eye loses vision

The objective is to review the most common causes of vision loss in patients with diabetes with the goal of better managing patients with diabetic eye disease. In this review, the causes of vision loss, and the clinical evaluation and management of diabetic retinopathy (DR) and diabetic macular edema (DME) are outlined. Patients with diabetes mellitus have an increased risk of vision loss and blindness. In patients with diabetes, the primary mechanism responsible for vision loss is centrally involved DME or clinically significant macular edema (CSME), defined as vascular leakage resulting in fluid accumulation that affects the center of the macula. DR and DME are thought to result from the effects of excessive blood glucose on the vessels that produces microvascular damage. The progression of DR can be slowed by intensive glycemic and blood pressure control. Severe visual loss from proliferative DR and moderate visual loss from DME can be reduced by laser photocoagulation. DR and DME are diagnosed on dilated retinal examination and confirmed with diagnostic testing. Many experts and associations recommend that patients with diabetes have an yearly, thorough, dilated eye exam. This manuscript describes the case history of a patient with diabetes and vision loss.

Kidney outcomes in long-term studies of ruboxistaurin for diabetic eye disease

BACKGROUND

A pilot study showed that ruboxistaurin (RBX), a protein kinase C beta inhibitor, significantly decreased albuminuria and stabilized kidney function over 1 yr in patients who had diabetic nephropathy and persistent macroalbuminuria despite receiving the current standard of care, including renin-angiotensin system inhibition. In contrast, in a trial of patients with diabetic retinopathy, investigators reported the adverse event "diabetic nephropathy" more frequently in patients who received RBX.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

The purpose of this study was to evaluate long-term effects of RBX on kidney outcomes among patients with diabetic eye disease in three diabetic retinopathy trials (n = 1157). Baseline-to-study end changes in estimated GFR (eGFR) were calculated. Kidney outcomes included doubling of serum creatinine, development of advanced chronic kidney disease (stages 4 to 5), and death.

RESULTS

Baseline eGFR was 81.6 +/- 26.0 ml/min per 1.73 m(2). In the combined placebo and RBX treatment groups, eGFR decreased by 11.0 +/- 19.6 ml/min per 1.73 m(2) during median follow-up of 33 to 39 mo. At least one kidney outcome occurred in 11.3% of patients. Frequency of doubling of serum creatinine was 6.0%, progression to advanced chronic kidney disease was 4.1%, and death was 4.1%. Kidney outcome rates did not differ by treatment assignment.

CONCLUSIONS

Long-term kidney outcomes in patients with diabetic eye disease were similar in placebo and RBX groups. In conclusion, large-scale, prospective trials in patients with diabetic nephropathy are needed to confirm safety and potential benefits of RBX on clinical outcomes.

Extracellular carbonic anhydrase mediates hemorrhagic retinal and cerebral vascular permeability through prekallikrein activation

Excessive retinal vascular permeability contributes to the pathogenesis of proliferative diabetic retinopathy and diabetic macular edema, leading causes of vision loss in working-age adults. Using mass spectroscopy-based proteomics, we detected 117 proteins in human vitreous and elevated levels of extracellular carbonic anhydrase-I (CA-I) in vitreous from individuals with diabetic retinopathy, suggesting that retinal hemorrhage and erythrocyte lysis contribute to the diabetic vitreous proteome. Intravitreous injection of CA-I in rats increased retinal vessel leakage and caused intraretinal edema. CA-I-induced alkalinization of vitreous increased kallikrein activity and its generation of factor XIIa, revealing a new pathway for contact system activation. CA-I-induced retinal edema was decreased by complement 1 inhibitor, neutralizing antibody to prekallikrein and bradykinin receptor antagonism. Subdural infusion of CA-I in rats induced cerebral vascular permeability, suggesting that extracellular CA-I could have broad relevance to neurovascular edema. Inhibition of extracellular CA-I and kallikrein-mediated innate inflammation could provide new therapeutic opportunities for the treatment of hemorrhage-induced retinal and cerebral edema.

Diabetic macular oedema: a clinical overview

Diabetic retinopathy is the leading cause of blindness in working aged-adults in westernised countries. Diabetic macular oedema (DMO) is a manifestation of diabetic retinopathy and is the leading cause of the visual impairment that occurs with diabetic retinopathy. There are multiple ways of classifying DMO; however, none appear to be wholly satisfactory. DMO occurs more frequently in type 2 diabetes mellitus, and appears to be more prevalent as the duration of diabetes increases, and as the severity of diabetic retinopathy worsens. There are multiple risk factors in common with diabetic retinopathy, such as hyperglycaemia, hypertension and dyslipidaemia; however, specific factors such as the presence of renal disease appear to be more significantly associated with DMO. Whereas the gold standard for diagnosis of DMO is via clinical examination, there is considerable variability involved, and hence, this has led to the advent of more objective methods of quantifying the degree of retinal thickness, such as optical coherence tomography. Laser photocoagulation appears to be the only universally acceptable treatment of choice to date; however, this is a destructive therapy, and its side effects coupled with the suboptimal efficacy has led to the advent of potential new therapies which will undoubtedly compliment the existing approaches, in the future management of a patient with DMO.

Incidence of sight-threatening retinopathy in Type 1 diabetes in a systematic screening programme

AIM

To measure the cumulative incidence of any retinopathy, maculopathy and sight-threatening diabetic retinopathy (STDR), and calculate optimal screening intervals by retinopathy grade at baseline for patients with Type 1 diabetes attending an established systematic retinal screening programme.

METHODS

All patients with Type 1 diabetes registered with enrolled general practitioners, excluding only those attending an ophthalmologist, were studied if retinopathy data was available at baseline and at least one further screen event. Screening utilized non-stereoscopic 3-field mydriatic photography and modified Wisconsin grading. STDR was defined as moderate pre-proliferative retinopathy or greater and/or significant maculopathy in any eye.

RESULTS

Patients (n=501) underwent 2742 screen events. Cumulative incidence of STDR in patients without baseline retinopathy was 0.3% (95% CI 0.0-0.9) at 1 year, rising to 3.9% (1.4-5.4) at 5 years. Rates of progression to STDR in patients with background and mild pre-proliferative retinopathy at 1 year were 3.6% (0.5-6.6) and 13.5% (4.2-22.7), respectively. Progression to STDR was greater in patients with a higher grade of baseline retinopathy (P=0.001) or a longer disease duration (P=0.003). For a 95% likelihood of remaining free of STDR, mean screening intervals by baseline status were: no retinopathy 5.7 (95% CI 3.5-7.6) years, background 1.3 (0.4-2.0) years and mild pre-proliferative 0.4 (0-0.8) years.

CONCLUSIONS

Screening at 2-3 year intervals, rather than annually, for patients without retinopathy in Type 1 diabetes is feasible because of the low risk of progression to STDR, and may result in significant cost savings for a screening programme. Patients with higher grades of retinopathy require screening at least annually or more frequent.

Incidence of sight-threatening retinopathy in patients with type 2 diabetes in the Liverpool Diabetic Eye Study: a cohort study

BACKGROUND

Incidence data on which to base targets and protocols for screening for sight-threatening diabetic retinopathy are few. We aimed to investigate yearly and cumulative incidence of any retinopathy, maculopathy, and sight-threatening diabetic retinopathy in patients with type 2 diabetes in an established systematic programme and to calculate optimum screening intervals according to retinopathy grade at baseline.

METHODS

We investigated all patients with type 2 diabetes registered with enrolled general practices (except those who were attending an ophthalmologist) who had retinopathy data available at baseline and at least one further screening event. To screen patients, we used non-stereoscopic three-field mydriatic photography and modified Wisconsin grading. Sight-threatening diabetic retinopathy was defined as moderate preproliferative retinopathy or worse, or clinically significant maculopathy in either or both eyes.

FINDINGS

Results were obtained from 20 570 screening events. Yearly incidence of sight-threatening diabetic retinopathy in patients without retinopathy at baseline was 0.3% (95% CI 0.1-0.5) in the first year, rising to 1.8% (1.2-2.5) in the fifth year; cumulative incidence at 5 years was 3.9% (2.8-5.0). Rates of progression to sight-threatening diabetic retinopathy in year 1 by baseline status were: background 5.0% (3.5-6.5), and mild preproliferative 15% (10.2-19.8). For a 95% probability of remaining free of sight-threatening diabetic retinopathy, mean screening intervals by baseline status were: no retinopathy 5.4 years (95% CI 4.7-6.3), background 1.0 years (0.7-1.3), and mild preproliferative 0.3 years (0.2-0.5).

INTERPRETATION

A 3-year screening interval could be safely adopted for patients with no retinopathy, but yearly or more frequent screening is needed for patients with higher grades of retinopathy.