Five-Year Cost-effectiveness of Intravitreous Ranibizumab Therapy vs Panretinal Photocoagulation for Treating Proliferative Diabetic Retinopathy: A Secondary Analysis of a Randomized Clinical Trial

Diabetic Retinopathy: New Treatment Approaches Targeting Redox and Immune Mechanisms

Diabetic retinopathy (DR) represents a severe complication of diabetes mellitus, characterized by irreversible visual impairment resulting from microvascular abnormalities. Since the global prevalence of diabetes continues to escalate, DR has emerged as a prominent area of research interest. The development and progression of DR encompass a complex interplay of pathological and physiological mechanisms, such as high glucose-induced oxidative stress, immune responses, vascular endothelial dysfunction, as well as damage to retinal neurons. Recent years have unveiled the involvement of genomic and epigenetic factors in the formation of DR mechanisms. At present, extensive research explores the potential of biomarkers such as cytokines, molecular and cell therapies, antioxidant interventions, and gene therapy for DR treatment. Notably, certain drugs, such as anti-VEGF agents, antioxidants, inhibitors of inflammatory responses, and protein kinase C (PKC)-β inhibitors, have demonstrated promising outcomes in clinical trials. Within this context, this review article aims to introduce the recent molecular research on DR and highlight the current progress in the field, with a particular focus on the emerging and experimental treatment strategies targeting the immune and redox signaling pathways.

Anti-Vascular Endothelial Growth Factor Drugs Compared With Panretinal Photocoagulation for the Treatment of Proliferative Diabetic Retinopathy: A Cost-Effectiveness Analysis

OBJECTIVES

This study aimed to evaluate the cost-effectiveness of anti-vascular endothelial growth factor drugs (anti-VEGFs) compared with panretinal photocoagulation (PRP) for treating proliferative diabetic retinopathy (PDR) in the United Kingdom.

METHODS

A discrete event simulation model was developed, informed by individual participant data meta-analysis. The model captures treatment effects on best corrected visual acuity in both eyes, and the occurrence of diabetic macular edema and vitreous hemorrhage. The model also estimates the value of undertaking further research to resolve decision uncertainty.

RESULTS

Anti-VEGFs are unlikely to generate clinically meaningful benefits over PRP. The model predicted anti-VEGFs be more costly and similarly effective as PRP, generating 0.029 fewer quality-adjusted life-years at an additional cost of £3688, with a net health benefit of -0.214 at a £20 000 willingness-to-pay threshold. Scenario analysis results suggest that only under very select conditions may anti-VEGFs offer potential for cost-effective treatment of PDR. The consequences of loss to follow-up were an important driver of model outcomes.

CONCLUSIONS

Anti-VEGFs are unlikely to be a cost-effective treatment for early PDR compared with PRP. Anti-VEGFs are generally associated with higher costs and similar health outcomes across various scenarios. Although anti-VEGFs were associated with lower diabetic macular edema rates, the number of cases avoided is insufficient to offset the additional treatment costs. Key uncertainties relate to the long-term comparative effectiveness of anti-VEGFs, particularly considering the real-world rates and consequences of treatment nonadherence. Further research on long-term visual acuity and rates of vision-threatening complications may be beneficial in resolving uncertainties.

Cost-Utility of Rhegmatogenous Retinal Detachment Repair With Pars Plana Vitrectomy, Scleral Buckle, and Pneumatic Retinopexy: A Microsimulation Model

PURPOSE

To assess the cost-effectiveness of primary noncomplex rhegmatogenous retinal detachment (RRD) repair, comparing 3 different strategies, pars plana vitrectomy (PPV), scleral buckle (SB), and pneumatic retinopexy (PnR) from the health care payer perspective over a lifetime.

DESIGN

Model-based cost-utility analysis.

METHODS

A simulated cohort of 100,000 adult patients (≥18 years old) requiring primary noncomplex RRD repair in theoretical surgical centers in the United States. Quality-adjusted life years (QALYs), lifetime costs (2022 United States dollars), and the incremental cost-effectiveness ratio (ICER) of the 3 interventions were projected over a lifetime horizon, with a cost-effectiveness threshold of ≤$50,000 per gained QALY.

RESULTS

Based on inputted parameters, the primary anatomical success was highest for PPV (95.00%) compared to SB (91.76%) and PnR (63.41%). The QALYs associated with PPV, SB, and PnR were (11.87, SD 1.62), (11.84, SD 1.63), and (11.59, SD 1.72), respectively. The incurred lifetime costs of RRD repair and associated postoperative surgeries for PPV, SB, and PnR were $4445.72 (SD 655.75), $4518.04 (662.92), and $3978.45 (728.50), respectively. Parameter-level simulations suggested that PPV was most likely to be the most cost-effective therapy compared to SB and PnR beyond a threshold of $3000/QALY. The incremental cost-effectiveness ratio for PPV compared to PnR was $1693.54. SB was dominant in all scenarios. Threshold analyses indicated that the success rate of PnR would have to be 100% and/or the cost would have to be $2000 or less over lifetime for it to be more cost-effective than PPV.

CONCLUSIONS

This study found PPV to be the most cost-effective primary procedure for RRD repair at a threshold of $50,000/QALY gained over a lifetime horizon from the health care payer perspective.

Machine learning regression algorithms to predict short-term efficacy after anti-VEGF treatment in diabetic macular edema based on real-world data

The objective of this retrospective study was to predict short-term efficacy of anti-vascular endothelial growth factor (VEGF) treatment in diabetic macular edema (DME) using machine learning regression models. Real-world data from 279 DME patients who received anti-VEGF treatment at Ineye Hospital of Chengdu University of TCM between April 2017 and November 2022 were analyzed. Eight machine learning regression models were established to predict four clinical efficacy indicators. The accuracy of the models was evaluated using mean absolute error (MAE), mean square error (MSE) and coefficient of determination score (R2). Multilayer perceptron had the highest R2 and lowest MAE among all models. Regression tree and lasso regression had similar R2, with lasso having lower MAE and MSE. Ridge regression, linear regression, support vector machines and polynomial regression had lower R2 and higher MAE. Support vector machine had the lowest MSE, while polynomial regression had the highest MSE. Stochastic gradient descent had the lowest R2 and high MAE and MSE. The results indicate that machine learning regression algorithms are valuable and effective in predicting short-term efficacy in DME patients through anti-VEGF treatment, and the lasso regression is the most effective ML algorithm for developing predictive regression models.

Cost-Utility Comparison of Bevacizumab and Aflibercept in the Treatment of Central or Hemiretinal Vein Occlusion in the SCORE2 Trial

Importance

Retinal vein occlusion is the second most common retinal vascular disease. Bevacizumab was demonstrated in the Study of Comparative Treatments for Retinal Vein Occlusion 2 (SCORE2) to be noninferior to aflibercept with respect to visual acuity in study participants with macular edema due to central retinal vein occlusion (CRVO) or hemiretinal vein occlusion (HRVO) following 6 months of therapy. In this study, the cost-utility of bevacizumab vs aflibercept for treatment of CRVO is evaluated.

Objective

To investigate the relative cost-effectiveness of bevacizumab vs aflibercept for treatment of macular edema associated with CRVO or HRVO.

Design, Setting, and Participants

This economic evaluation study used a microsimulation cohort of patients with clinical and demographic characteristics similar to those of SCORE2 participants and a Markov process. Parameters were estimated and validated using a split-sample approach of the SCORE2 population. The simulated cohort included 5000 patients who were evaluated 100 times, each with a different set of characteristics randomly selected based on the SCORE2 trial. SCORE2 data were collected from September 2014 October 2019, and data were analyzed from October 2019 to July 2021.

Interventions

Bevacizumab (followed by aflibercept among patients with a protocol-defined poor or marginal response to bevacizumab at month 6) vs aflibercept (followed by a dexamethasone implant among patients with a protocol-defined poor or marginal response to aflibercept at month 6).

Main Outcomes and Measures

Incremental cost-utility ratio.

Results

The simulation demonstrated that patients treated with aflibercept will have an expected cost $18 127 greater than those treated with bevacizumab in the year following initiation. When coupled with the lack of clinical superiority over bevacizumab (ie, patients treated with bevacizumab had a gain over aflibercept in visual acuity letter score of 4 in the treated eye and 2 in the fellow eye), these results demonstrate that first-line treatment with bevacizumab dominated aflibercept in the simulated cohort of SCORE2 participants. At current price levels, aflibercept would be considered the preferred cost-effective option only if treatment restored the patient to nearly perfect health.

Conclusions and Relevance

While there will be some patients with CRVO-associated or HRVO-associated macular edema who will benefit from first-line treatment with aflibercept rather than bevacizumab, given the minimal differences in visual acuity outcomes and large cost differences for bevacizumab vs aflibercept, first-line treatment with bevacizumab is cost-effective for this condition.

Update on the Management of Diabetic Retinopathy: Anti-VEGF Agents for the Prevention of Complications and Progression of Nonproliferative and Proliferative Retinopathy

Diabetic retinopathy (DR) is a microvascular disease caused by poorly controlled blood glucose, and it is a leading cause of vision loss in people with diabetes. In this review we discuss the current management of DR with particular focus on the use of intraocular anti-vascular endothelial growth factor (anti-VEGF) agents. Intraocular anti-VEGF agents were first studied in the 1990s, and now several of these agents are either FDA approved or used off-label as first-line treatments for DR. Recent evidence shows that anti-VEGF agents can halt the progression of markers of DR severity, reduce the risk of DR worsening, and reduce the onset of new macular edema. These significant benefits have been demonstrated in patients with proliferative DR and the milder nonproliferative DR (NPDR). A wealth of evidence from recent trials and meta-analyses has detailed the intraoperative and postoperative benefits of adjunctive anti-VEGF therapy prior to pars plana vitrectomy (PPV) for proliferative DR with vitreous hemorrhage. In this review, we also discuss literature comparing various anti-VEGF injection regimens including monthly, quarterly, as-needed, and treat and extend protocols. Combination protocols with panretinal photocoagulation (PRP) or PPV are also discussed. Current evidence suggests that anti-VEGF therapies are effective therapy for NPDR and PDR and may also provide significant benefits when used adjunctively with other DR treatment modalities such as PRP or PPV.

Anti-vascular endothelial growth factor for proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is an advanced complication of diabetic retinopathy that can cause blindness. It consists of the presence of new vessels in the retina and vitreous haemorrhage. Although panretinal photocoagulation (PRP) is the treatment of choice for PDR, it has secondary effects that can affect vision. Anti-vascular endothelial growth factor (anti-VEGF), which produces an inhibition of vascular proliferation, could improve the vision of people with PDR.

OBJECTIVES

To assess the effectiveness and safety of anti-VEGFs for PDR and summarise any relevant economic evaluations of their use.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov, and the WHO ICTRP. We did not use any date or language restrictions. We last searched the electronic databases on 1 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing anti-VEGFs to another active treatment, sham treatment, or no treatment for people with PDR. We also included studies that assessed the combination of anti-VEGFs with other treatments. We excluded studies that used anti-VEGFs in people undergoing vitrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, and assessed the risk of bias (RoB) for all included trials. We calculated the risk ratio (RR) or the mean difference (MD), and 95% confidence intervals (CI). We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 15 new studies in this update, bringing the total to 23 RCTs with 1755 participants (2334 eyes). Forty-five per cent of participants were women and 55% were men, with a mean age of 56 years (range 48 to 77 years). The mean glycosylated haemoglobin (Hb1Ac) was 8.45% for the PRP group and 8.25% for people receiving anti-VEGFs alone or in combination. Twelve studies included people with PDR, and participants in 11 studies had high-risk PDR (HRPDR). Twelve studies were of bevacizumab, seven of ranibizumab, one of conbercept, two of pegaptanib, and one of aflibercept. The mean number of participants per RCT was 76 (ranging from 15 to 305). Most studies had an unclear or high RoB, mainly in the blinding of interventions and outcome assessors. A few studies had selective reporting and attrition bias. No study reported loss or gain of 3 or more lines of visual acuity (VA) at 12 months. Anti-VEGFs ± PRP probably increase VA compared with PRP alone (mean difference (MD) -0.08 logMAR, 95% CI -0.12 to -0.04; I2 = 28%; 10 RCTS, 1172 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP may increase regression of new vessels (MD -4.14 mm2, 95% CI -6.84 to -1.43; I2 = 75%; 4 RCTS, 189 eyes; low-certainty evidence) and probably increase a complete regression of new vessels (RR 1.63, 95% CI 1.19 to 2.24; I2 = 46%; 5 RCTS, 405 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP probably reduce vitreous haemorrhage (RR 0.72, 95% CI 0.57 to 0.90; I2 = 0%; 6 RCTS, 1008 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP may reduce the need for vitrectomy compared with eyes that received PRP alone (RR 0.67, 95% CI 0.49 to 0.93; I2 = 43%; 8 RCTs, 1248 eyes; low-certainty evidence). Anti-VEGFs ± PRP may result in little to no difference in the quality of life compared with PRP alone (MD 0.62, 95% CI -3.99 to 5.23; I2 = 0%; 2 RCTs, 382 participants; low-certainty evidence). We do not know if anti-VEGFs ± PRP compared with PRP alone had an impact on adverse events (very low-certainty evidence). We did not find differences in visual acuity in subgroup analyses comparing the type of anti-VEGFs, the severity of the disease (PDR versus HRPDR), time to follow-up (< 12 months versus 12 or more months), and treatment with anti-VEGFs + PRP versus anti-VEGFs alone. The main reasons for downgrading the certainty of evidence included a high RoB, imprecision, and inconsistency of effect estimates.

AUTHORS' CONCLUSIONS

Anti-VEGFs ± PRP compared with PRP alone probably increase visual acuity, but the degree of improvement is not clinically meaningful. Regarding secondary outcomes, anti-VEGFs ± PRP produce a regression of new vessels, reduce vitreous haemorrhage, and may reduce the need for vitrectomy compared with eyes that received PRP alone. We do not know if anti-VEGFs ± PRP have an impact on the incidence of adverse events and they may have little or no effect on patients' quality of life. Carefully designed and conducted clinical trials are required, assessing the optimal schedule of anti-VEGFs alone compared with PRP, and with a longer follow-up.

Cost-effectiveness Analysis of a Personalized, Teleretinal-Inclusive Screening Policy for Diabetic Retinopathy via Markov Modeling

PURPOSE

Although teleretinal imaging has proved effective in increasing population-level screening for diabetic retinopathy (DR), there is a lack of quantitative understanding of how to incorporate teleretinal imaging into existing screening guidelines. We develop a mathematical model to determine personalized DR screening recommendations that utilize teleretinal imaging and evaluate the cost-effectiveness of the personalized screening policy.

DESIGN

A partially observable Markov decision process is employed to determine personalized screening recommendations based on patient compliance, willingness to pay, and A1C level. Deterministic sensitivity analysis was conducted to evaluate the impact of patient-specific factors on personalized screening policy. The cost-effectiveness of identified screening policies was evaluated via hidden-Markov chain Monte Carlo simulation on a data-based hypothetical cohort.

PARTICIPANTS

Screening policies were simulated for a hypothetical cohort of 500 000 patients with parameters based on the literature and electronic medical records of 2457 patients who received teleretinal imaging from 2013 to 2020 from the Harris Health System.

METHODS

Population-based mathematical modeling study. Interventions included dilated fundus examinations referred to as clinical screening, teleretinal imaging, and wait and watch recommendations.

MAIN OUTCOME MEASURES

Personalized screening recommendations based on patient-specific factors. Accumulated quality-adjusted life-years (QALYs) and cost (USD) per patient under different screening policies. Incremental cost-effectiveness ratio to compare different policies.

RESULTS

For the base cohort, on average, teleretinal imaging was recommended 86.7% of the time over each patient's lifetime. The model-based personalized policy dominated other standardized policies, generating more QALY gains and cost savings for at least 57% of the base cohort. Similar outcomes were observed in sensitivity analyses of the base cohort and the Harris Health-specific cohort and rural population scenario analysis.

CONCLUSIONS

A mathematical model was developed as a decision support tool to identify a personalized screening policy that incorporates both teleretinal imaging and clinical screening and adapts to patient characteristics. Compared with current standardized policies, the model-based policy significantly reduces costs, whereas it is performing comparably, if not better, in terms of QALY gain. A personalized approach to DR screening has significant potential benefits that warrant further exploration.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

A systematic review and meta-analysis of the effect of intravitreal VEGF inhibitors on cardiorenal outcomes

BACKGROUND

Vascular endothelial growth factor inhibitors (VEGFi) have transformed the treatment of many retinal diseases, including diabetic maculopathy. Increasing evidence supports systemic absorption of intravitreal VEGFi and development of significant cardiorenal side effects.

METHODS

Systematic review and meta-analysis (PROSPERO: CRD42020189037) of randomised controlled trials of intravitreal VEGFi treatments (bevacizumab, ranibizumab and aflibercept) for any eye disease. Outcomes of interest were cardiorenal side effects (hypertension, proteinuria, kidney function decline and heart failure). Fixed-effects meta-analyses were conducted where possible.

RESULTS

There were 78 trials (81 comparisons; 13 175 participants) that met criteria for inclusion: 47% were trials in diabetic eye disease. Hypertension (29 trials; 8570 participants) was equally common in VEGFi and control groups (7.3 versus 5.4%; RR 1.08 [0.91; 1.28]). New or worsening heart failure (10 trials; 3384 participants) had similar incidence in VEGFi and control groups (RR 1.03 [0.70; 1.51]). Proteinuria (5 trials; 1902 participants) was detectable in some VEGFi-treated participants (0.2%) but not controls (0.0%; RR 4.43 [0.49; 40.0]). Kidney function decline (9 trials; 3471 participants) was similar in VEGFi and control groups. In participants with diabetic eye disease, risk of all-cause mortality was higher in VEGFi-treated participants (RR 1.62 [1.04; 2.46]).

CONCLUSION

In trials of intravitreal VEGFi, we did not identify an increased risk of cardiorenal outcomes, though these outcomes were reported in only a minority of cases. There was an increased risk of death in VEGFi-treated participants with diabetic eye disease. Additional scrutiny of post-licensing observational data may improve recognition of safety concerns in VEGFi-treated patients.

Potential impact of fluorescein angiography as a primary imaging modality in the management of diabetic retinopathy

Purpose

To evaluate current practice patterns for Egyptian ophthalmologists in the diagnosis of diabetic retinopathy (DR) and explore potential implications of these approaches on management.

Methods

Cross-sectional survey conducted in Egypt amongst practicing ophthalmologists.

Results

The study had 203 responses (~6% of all Egyptian ophthalmologists). A majority of respondents were general ophthalmologists (78.2%), practicing for five to ten years (41.9%). In patients with DR and no diabetic macular edema (DME), 33.0% of respondents would use FA in patients with mild DR, 44.3% in patients with moderate DR and 51.2% in patients with severe non-proliferative diabetic retinopathy (NPDR). Color imaging (CI) was used by less than 1% as the sole imaging modality for any level of DR. Approximately 70% of respondents used fluorescein angiography (FA) to grade and base treatment decisions for DR, either alone or in conjunction with dilated eye exams and/or CI. Given the known more severe appearance of DR on FA than on standard color imaging upon which treatment guidelines are based, use of FA as the primary modality over a one-year period could result in PRP that would otherwise not be suggested in approximately 78,820 eyes at an additional cost of $10.1 million US dollars. These numbers are projected to double by 2045.

Conclusion

Given that FA detects significantly greater pathology than CI, and that treatment and follow-up recommendations are based on CI, its use as the primary imaging modality in DR grading may result in apparently significantly higher DR severity, with subsequently increased procedures and associated costs.

A Paradigm Shift in the Management Approaches of Proliferative Diabetic Retinopathy: Role of Anti-VEGF Therapy

Diabetic retinopathy (DR) is considered one of the leading causes of vision loss globally. It principally causes upregulation of pro-angiogenic, proinflammatory, and vascular permeability factors such as vascular endothelial growth factor (VEGF), leading to neovascularisation. The advanced stage of DR or proliferative diabetic retinopathy (PDR) is of more concern, as it leads to vitreous haemorrhage and traction retinal detachment. Various risk factors associated with PDR include hyperglycemia, hypertension, neuropathy, dyslipidemia, anaemia, nephropathy, and retinal complications of drugs used for diabetes. Current management approaches for PDR have been stratified and involve pan-retinal photocoagulation, vitrectomy, and anti-VEGF agents. Given the emerging role of anti-VEGF agents as a favourable adjunct or alternative therapy, they have a critical role in the management of PDR. The review emphasises current management approaches for PDR focusing on anti-VEGF therapy. The review also highlights the risk/benefit evaluation of the various approaches employed for PDR management in various clinical scenarios.

Diabetic Macular Edema Treatment: Laser Photocoagulation Versus anti-VEGF Drugs

Abstract: Objective: The present study was aimed to compare best-corrected vision and central macular thickness for macular edema in diabetes (DME) after utilizing laser, Avastin, and Lucentis. Methods: A retrospective randomized cross-sectional study was conducted at Alfaisal Eye Center, Khartoum. Best-corrected vision and central macular thickness (CMT) were assessed by Snellen's chart and Heidelberg optical coherence tomography OCT, respectively. Results: In this study, a total of 252 records of DME-treated patients with laser applications, Avastin, and Lucentis were enrolled, their mean age was 57 ± 5.22 yrs. A significant enhancement in best-corrected vision and CMT of studied groups with laser applications, Avastin, and Lucentis was obtained (P= 0.000) with no differences between treated groups (p= 0.445 and 0,479), respectively. Non-significant differences in variable measurements related to gender or age (p = 0.117, 0.781), respectively. CMT of females (260 ± 48 μm) was thinner than males (306 ± 74 μm) after treatment (P = 0.000). Conclusion: laser applications, Avastin, and Lucentis improved best-corrected vision and reduced central macular thickness significantly with no clear differences between studied groups. Age or gender have a non-significant impact on dependent variables. Females gained thinner results compared to males after treatment.  

The economics of vision impairment and its leading causes: A systematic review

Vision impairment (VI) can have wide ranging economic impact on individuals, households, and health systems. The aim of this systematic review was to describe and summarise the costs associated with VI and its major causes. We searched MEDLINE (16 November 2019), National Health Service Economic Evaluation Database, the Database of Abstracts of Reviews of Effects and the Health Technology Assessment database (12 December 2019) for partial or full economic evaluation studies, published between 1 January 2000 and the search dates, reporting cost data for participants with VI due to an unspecified cause or one of the seven leading causes globally: cataract, uncorrected refractive error, diabetic retinopathy, glaucoma, age-related macular degeneration, corneal opacity, trachoma. The search was repeated on 20 January 2022 to identify studies published since our initial search. Included studies were quality appraised using the British Medical Journal Checklist for economic submissions adapted for cost of illness studies. Results were synthesized in a structured narrative. Of the 138 included studies, 38 reported cost estimates for VI due to an unspecified cause and 100 reported costs for one of the leading causes. These 138 studies provided 155 regional cost estimates. Fourteen studies reported global data; 103/155 (66%) regional estimates were from high-income countries. Costs were most commonly reported using a societal (n = 48) or healthcare system perspective (n = 25). Most studies included only a limited number of cost components. Large variations in methodology and reporting across studies meant cost estimates varied considerably. The average quality assessment score was 78% (range 35-100%); the most common weaknesses were the lack of sensitivity analysis and insufficient disaggregation of costs. There was substantial variation across studies in average treatment costs per patient for most conditions, including refractive error correction (range $12-$201 ppp), cataract surgery (range $54-$3654 ppp), glaucoma (range $351-$1354 ppp) and AMD (range $2209-$7524 ppp). Future cost estimates of the economic burden of VI and its major causes will be improved by the development and adoption of a reference case for eye health. This could then be used in regular studies, particularly in countries with data gaps, including low- and middle-income countries in Asia, Eastern Europe, Oceania, Latin America and sub-Saharan Africa.

Ocular manifestations of endocrine disorders

Endocrinopathies are prevalent diseases that typically affect multiple organs, and the eye and orbital tissues are often involved in endocrine disorders. Some conditions, such as diabetes and thyroid gland dysfunction, may cause serious eye pathology and even blindness. A clear insight into the pathogenesis of endocrinopathies and their ocular manifestations would enhance preventive and therapeutic measures and reduce the incidence of sight-threatening complications. This review discusses the ocular manifestations of several endocrine disorders that eye care providers are likely to encounter in clinical practice.

The Role of Ultra-Widefield Fundus Imaging and Fluorescein Angiography in Diagnosis and Treatment of Diabetic Retinopathy

PURPOSE OF REVIEW

Early detection and treatment are important for preventing vision loss from diabetic retinopathy. Historically, the gold standard for grading diabetic retinopathy has been based on 7-field 30-degree color fundus photographs that capture roughly the central third of the retina. Our aim was to review recent literature on the role of ultra-widefield (allowing capture of up to 82% of the retina in one frame) fundus imaging in screening, prognostication, and treatment of diabetic retinopathy.

RECENT FINDINGS

Ultra-widefield fundus imaging can capture peripheral retinal lesions outside the traditional 7-field photographs that may correlate with increased risk of diabetic retinopathy progression. The speed and ability to image through undilated pupils make ultra-widefield imaging attractive for tele-ophthalmology screening. Ultra-widefield fluorescein angiography may help guide targeted laser treatment in eyes with proliferative diabetic retinopathy. Ultra-widefield imaging has potential to help shape new diabetic retinopathy screening, staging, and treatment protocols.

Intravitreal Anti-Vascular Endothelial Growth Factor Agents for the Treatment of Diabetic Retinopathy: A Review of the Literature

Background: Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population. The purpose of this review is to gather the existing literature regarding the use of the approved anti-vascular endothelial growth (anti-VEGF) agents in the treatment of DR. Methods: A comprehensive literature review in PubMed engine search was performed for articles written in English language up to 1 July 2021, using the keywords “diabetic retinopathy”, “ranibizumab”, “aflibercept”, and “anti-VEGF”. Emphasis was given on pivotal trials and recent robust studies. Results: Intravitreal anti-VEGF agents have been found to significantly improve visual acuity and reduce retinal thickness in patients with diabetic macular edema (DME) in a long-term follow-up ranging from 1 to 5 years and are considered the standard-of-care in such patients. Regarding DR, intravitreal anti-VEGF agents provided ≥2-step improvement in DR severity on color fundus photography in about 30–35% of patients with NPDR at baseline, in the majority of clinical trials originally designed to evaluate the efficacy of intravitreal anti-VEGF agents in patients with DME. Protocol S and CLARITY study have firstly reported that intravitreal anti-VEGF agents are non-inferior to panretinal photocoagulation (PRP) in patients with proliferative DR (PDR). However, the use of new imaging modalities, such as optical coherence tomography-angiography and wide-field fluorescein angiography, reveals conflicting results about the impact of anti-VEGF agents on the regression of retinal non-perfusion in patients with DR. Furthermore, one should consider the high “loss to follow-up” rate and its devastating consequences especially in patients with PDR, when deciding to treat the latter with intravitreal anti-VEGF agents alone compared to PRP. In patients with PDR, combination of treatment of intravitreal anti-VEGF agents and PRP has been also supported. Moreover, in the specific case of vitreous hemorrhage or tractional retinal detachment as complications of PDR, intravitreal anti-VEGF agents have been found to be beneficial as an adjunct to pars plana vitrectomy (PPV), most commonly given 3–7 days before PPV, offering reduction in the recurrence of vitreous hemorrhage. Conclusions: There is no general consensus regarding the use of intravitreal anti-VEGF agents in patients with DR. Although anti-VEGF agents are the gold standard in the treatment of DME and seem to improve DR severity, challenges in their use exist and should be taken into account in the decision of treatment, based on an individualized approach.

Clinical efficacy of anti-vascular endothelial growth factor versus panretinal photocoagulation for patients with proliferative diabetic retinopathy: A protocol for systematic review and meta-analysis

BACKGROUND

The argument on the optimal treatment for patients with proliferative diabetic retinopathy (PDR) remains to be resolved. Therefore, the primary objective of the present study was to evaluate the clinical efficacy of anti-vascular endothelial growth factor (anti-VEGF) therapy versus panretinal photocoagulation (PRP) for patients with PDR.

METHODS

Two independent investigators followed The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines and the recommendations of the Cochrane Collaboration to conduct this meta-analysis. The electronic databases of EMBASE, PubMed, Cochrane Library, and Web of Science were searched from the inception to April 2021 using the following key terms: "proliferative diabetic retinopathy," "anti-vascular endothelial growth factor," and "panretinal photocoagulation," for all relevant studies. We identified literature that met the following inclusion criteria: patients with PDR; studies focusing on assessing anti-VEGF therapy and PRP; the following outcome measures must be shown: anatomical outcomes, including complete regression and recurrence of neovascularization, mean change in best corrected vision acuity from baseline to the end of follow-up period. The Cochrane risk of bias tool was used to evaluate the risk of bias of included randomized clinical trials by 2 independent reviewers.

RESULTS

This protocol will provide a reliable theoretical basis for the following research.

TRIAL REGISTRATION NUMBER

10.17605/OSF.IO/UHYDR.

Quantifying Conflict of Interest in the Choice of Anti-VEGF Agents

Purpose

To quantify the economic incentives associated with the choice of anti-VEGF drugs for retinal diseases.

Methods

An economic model was created based on the distribution of use and number of injections of bevacizumab (B), versus aflibercept or ranibizumab (AR); published Medicare reimbursement rates; published rebates; estimated unreimbursed drug use; estimated use of drug company samples; and published costs-of-drugs. Differential economic incentives associated with the choice of drugs were calculated over a range of distributions of drug use.

Results

The splits in drug choice ranged from 92% AR/8% B to 31% AR/69% B, and in annual injection numbers from 2000 to 6000 with a median of 4000 in one 5-person retina service. Assumed values for rebates were 1% for drug company rebate, 1% for group purchasing organization rebate, and 5 for number of unreimbursed injections per year. The differential economic incentive of a 92% AR/8% B split compared to a 31% AR/69% B split for the median annual number of injections was $266, 893.

Conclusion

Using real-world data, the economic incentive associated with a choice of more expensive anti-VEGF drugs is large. Accounting for unreimbursed drug use and the cost of additional staff required to manage expensive drug inventory does not nullify the incentive. To what degree this financial incentive influences ophthalmologists’ choice of drugs is unknown, but not trivial. Financial disclosure of the conflicts of interest in the drugs recommended for treatment should be discussed with patients.

Real-world outcomes of two-year Conbercept therapy for diabetic macular edema

AIM

To evaluate the two-year outcomes of patients treated for diabetic macular edema (DME) with intravitreal Conbercept (IVC).

METHODS

The clinical data of 30 DME patients (36 eyes) were retrospectively reviewed. The patients were treated with IVC for 3mo. Additional IVC was given at subsequent monthly visits, if needed (3+PRN). The patients were followed up for 24mo.

RESULTS

The best-corrected visual acuity (BCVA) at 24mo significantly increased (66.7±15.3 letters) in comparison with the baseline (54.4±15.4 letters, P<0.0001). The mean improvement in BCVA was 11.0±2.9 letters. At 24mo, 44.1% of the eyes surveyed gained ≥15 letters, 52.9% of the eyes gained ≥10 letters, and 70.6% of the eyes gained ≥5 letters. No vision loss was noted in 96.8% of the eyes, and 5.9% of the eyes lost ≥5 letters, but ≤10 letters. The central retinal thickness (CRT) at 24mo was significantly reduced (277.1±122.9 µm) in comparison with the baseline (510.9±186.1 µm, P<0.0001). At 24mo, 43.3% of the patients had a CRT ≤250 µm. The mean number of injections over 24mo was 10.6±2.0. No severe eye or systemic adverse events related to either the drug or injection were noted.

CONCLUSION

IVC is safe and effective for the treatment of DME.

Evaluation of real-world early response of DMO to aflibercept therapy to inform future clinical trial design of novel investigational agents

New clinical trials for diabetic macular oedema (DMO) are being designed to prove superiority over aflibercept when this agent is already very effective in improving visual acuity (VA) and DMO. The aim of this study was to determine the optimal inclusion–exclusion criteria for trials to aim for superiority in visual outcomes with newer agents. As Phase 1 studies are short duration, we aimed to evaluate the early response of aflibercept in a real-world cohort initiated on monthly aflibercept for 3 consecutive injections and observed the effects at 4 months. The sub-optimal responders were pre-defined based on different cut-offs for VA and central sub-field thickness (CST). 200 patients with treatment naïve DMO treated with 3 loading doses of aflibercept were included in the study. We found that those presenting with baseline VA of 35–54 ETDRS letters (n = 43) had higher proportion of sub-optimal responders compared to other categories (p < 0.001). Patients with baseline CST of less than 400 µm (n = 96) responded less well functionally and anatomically to loading dose than eyes with baseline CST of 400 µm or more (n = 104, p = 0.02), indicating that eyes with CST ≥ 400 µm is another inclusion criteria. There was minimal correlation between change in CST and change in VA at 4 months (r = − 0.27), suggesting that both these inclusion criteria are non-exclusive. However, for maximal efficacy, patients that meet both these inclusion criteria are more likely to show benefit from an alternative intervention. New trials should aim to include patients with treatment naïve DMO with VA between 35–54 letters and CST of 400 µm or more when aflibercept is used as the comparator.

Intravitreal ranibizumab alone or in combination with panretinal photocoagulation for the treatment of proliferative diabetic retinopathy with coexistent macular edema: long-term outcomes of a prospective study

AIMS

To compare intravitreal ranibizumab as monotherapy or in combination with panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PDR) and coexistent diabetic macular edema (DME) in a long-term follow-up of 24 months.

METHODS

Participants in this prospective study were 47 patients with PDR and concurrent DME, who were randomized at baseline into two groups: (i) the "ranibizumab alone" group (n = 23), which was treated with at least 3 intravitreal ranibizumab injections as a loading phase, and (ii) the "combination" group (n = 24), which was treated with PRP and at least 3 intravitreal ranibizumab injections. Thereafter, all patients were followed up at a pro re nata (PRN) basis, with regular monthly monitoring for 24 months. At each visit, best corrected visual acuity (BCVA) and spectral domain-optical coherence tomography were performed, while regression of neovascularization was also recorded.

RESULTS

The "combination" group had better control of neovascularization and less events of vitreous hemorrhage than ranibizumab alone through the 2 years. BCVA did not differ significantly between the two groups at months 12 and 24 of the follow-up. The "ranibizumab" alone group presented greater reduction in central retinal thickness at month 12, which did not reach significance at month 24 compared to "combination" group. Greater number of injections was needed in the monotherapy group (mean 14 injections) compared to "combination" group (mean 11 injections) through month 24.

CONCLUSIONS

Both intravitreal ranibizumab alone or in combination with PRP could be used effectively for the treatment of PDR and coexistent DME. Even though there was no difference in BCVA and CRT at the 24-month follow-up between the two groups, the combination group presented greater regression of neovascularization with less injections.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

Profile of non-responder and late responder patients treated for diabetic macular edema: systemic and ocular factors

Diabetic macular edema (DME) treatment represents a challenge for the ophthalmologists, and several aspects of real treatment expectancy are still being discussed and not yet fully elucidated. A univocal definition of responsiveness to treatment has not been reached. How the clinicians can evaluate the therapeutic success? The evaluation of systemic and ocular factors should help in this complex management. The age influences the long-term outcomes, and the role of glycemic control is confounded by contrasting correlations between hemoglobin glycated A1c and DME. Long-term treatment success is influenced by baseline best-corrected visual acuity (BCVA), central macular thickness (CMT) and early BCVA response. Also baseline diabetic retinopathy severity scale score is useful to evaluate the chances of improvement before and during treatments. The time-switching was influenced by early BCVA response, however considering a delayed response in a percentage of patients. Several structural optical coherence tomography (OCT) findings could predict long-term success, as the presence of serous retinal detachment, hyperreflective retinal spots, the disruption of external limiting membrane and ellipsoid zone, the disorganization of inner retinal layers and continued increase in CMT were considered predictors of poor response to treatment. Foveal avascular zone enlargement, high number of microaneurysms (Mas), lower vessel density (VD) in deep capillary plexus and lower parafoveal VD in superficial capillary plexus were considered as OCT angiography biomarkers of poor responsiveness. The aim of this review is to report the factors that could influence the response to treatment of DME patients.

Do we have enough ophthalmologists to manage vision-threatening diabetic retinopathy? A global perspective

We aimed to estimate the supply of ophthalmologists in relation to the global and regional burden of vision-threatening diabetic retinopathy (VTDR). Diabetes mellitus (DM) population data from seven world regions were obtained from the International Diabetes Federation Atlas 2017. A systematic review was performed to include population-, community-based studies that reported country-specific VTDR prevalence. Random effect meta-analysis was then performed to estimate global and regional VTDR prevalence. VTDR prevalence estimates coupled with DM population data were then used to estimate the number of VTDR cases. Global and regional number of ophthalmologists were derived from the International Council of Ophthalmology Report 2015. Fifty studies (17 from Western Pacific [WP], nine North America and Caribbean [NAC], nine Middle East and North Africa [MENA], five Europe, eight South East Asia [SEA], one South and Central America [SACA] and one from Africa) were included. Global VTDR prevalence was 7.26% (95% CI, 6.18-8.32%). Regional VTDR prevalence was 14.35% in Africa, 11.21% in MENA, 10.00% in NAC, 6.32% in Europe, 6.22% in WP, 5.83% in SACA and 2.97% in SEA. Globally, there were 7.16 ophthalmologists per 1000 VTDR patients. Europe had the highest ophthalmologist per 1000 VTDR patient ratio at 18.03 followed by SACA (17.41), while NAC, MENA and Africa had the lowest at 4.90, 4.81 and 0.91 respectively. Across regions, the ophthalmologist densities ranged from 0.91 to 18.03 per 1000 VTDR patients, with NAC, MENA and Africa having less than 5 ophthalmologists per 1000 patients. These findings will aid global and regional policy planning and healthcare resource allocation for VTDR management.