Worsening of diabetic retinopathy with rapid improvement in systemic glucose control: A review

Reversible bilateral central scotoma under scotopic conditions associated with oral semaglutide

Introduction

Semaglutide is a glucagon-like peptide-1 receptor agonist that treats type 2 diabetes mellitus and can be used as an adjunct for weight loss when combined with exercise and diet. Here we report a case of a bilateral, incongruent central visual scotoma under scotopic conditions in a board-certified ophthalmologist associated with semaglutide use that resolved quickly following medication discontinuation.

Case report

A 72-year-old male ophthalmologist (JAD) started 3.0 mg daily oral semaglutide (Rybelsus) to help with weight loss and seventeen days after treatment initiation developed a small, round central scotoma in his right eye that enlarged over several days. After two days a similar but smaller scotoma developed in his left eye. These symptoms were present only under scotopic conditions and were not visible in daylight or artificially lit conditions. When symptoms developed in the left eye, the medication was discontinued, and all symptoms completely resolved two days later. A subsequent clinical evaluation revealed no abnormalities on macular optical coherence tomography, fundus photography, fundus autofluorescence or Humphrey visual field.

Conclusions

This case of a bilateral central scotoma under scotopic conditions that resolved after medication discontinuation expands the knowledge of potential side effects from this increasingly popular diabetic and weight loss medication.

The Effect of Glucagon-Like Peptide-1 Receptor Agonists on Diabetic Retinopathy at a Tertiary Care Center

Objective

The potential association between diabetic retinopathy (DR) worsening and glucagon-like peptide-1 receptor agonists (GLP-1RA) has affected therapeutic management of diabetic patients but remains controversial. This study compared rates of DR development or progression in patients on GLP-1RA to those on SGLT-2 inhibitors (SGLT-2I).

Design

Retrospective cohort study.

Subjects

Nine hundred eighty-one patients with diabetes mellitus taking GLP-1RA or SGLT-2I, the latter serving as controls, between 2012 and 2023.

Methods

Patients were one-to-one greedy matched by propensity scores on race/ethnicity, age, smoking status, baseline body mass index and hemoglobin A1c %, type of diabetes mellitus, baseline DR status and history of DR procedures, duration of drug use, whether they had taken both drug types, and change in hemoglobin A1c % after 1 year on the drug.

Main Outcome Measures

The primary outcome was clinical DR development or progression (termed "worsening") detected by International Classification of Diseases (ICD), 10th edition codes, confirmed by manual review, on GLP-1RA compared with SGLT-2I after propensity score matching. Secondary outcomes included DR worsening indicated by need for procedures due to complications, and time-to-first DR worsening event.

Results

The study included 692 GLP-1RA users and 289 SGLT-2I users. The mean follow-up periods for GLP-1RA versus SGLT-2I use were 1.54 (standard deviation [SD] 1.82) years and 1.38 (SD 1.56) years, respectively. The rates of clinical worsening were 2.3% and 2.8%, respectively. After propensity score matching, an association was not identified between GLP1-RA and DR worsening neither clinically by ICD-10 codes (odds ratio [OR] = 0.33, 95% confidence interval [CI]: 0.11-1.03) nor by indication for procedures (OR = 0.50, 95% CI 0.13-2.00). Time-to-first DR worsening did not differ between the groups in Kaplan-Meier analysis. The most common type of clinical worsening event for both drug types was vitreous hemorrhage (43.7% and 50% of worsening events in GLP-1RA and SGLT-2I users, respectively). The most common DR procedure indicated was anti-VEGF injections (34% and 35% of GLP-1RA and SGLT-2I events, respectively).

Conclusions

Diabetic retinopathy worsening, either clinically or by procedures, was not associated with GLP-1RA compared with SGLT-2I, both before and after propensity score matching on all analyses, including time-to-first worsening event.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Glucagon-Like Peptide-1 Receptor Agonists are Not Associated with an Increased Risk of Progressing to Vision-Threatening Diabetic Retinopathy

PURPOSE

Glucagon-like peptide-1 receptor agonists (GLP-1RA) are used to treat type 2 diabetes mellitus (DM) by augmenting insulin release and sensitivity. We assessed the overall risk for development of vision-threatening diabetic retinopathy (VTDR), proliferative diabetic retinopathy (PDR), and diabetic macular edema (DME), among GLP-1RA users.

METHODS

A retrospective cohort of patients with NPDR newly started on a GLP-1RA from a national insurance claims database was compared to a cohort of patients treated with other oral anti-diabetic agents and matched for age, sex, race, index year, and number of active diabetic medications. Exclusions occurred for < 2 years in the database before diagnosis; prior diagnoses of PDR, DME, vitreous hemorrhage, and/or other retinal vascular diseases; and prior intraocular treatment for VTDR.

RESULTS

A total of 6093 users of GLP-1RA were matched to 14,122 controls. In the GLP-1RA cohort, 632 (10.1%), 76 (1.2%), and 544 (8.9%) patients progressed to VTDR, PDR, or DME, respectively. This is compared to 1332 (9.5%) VTDR, 165 (1.2%) PDR, or 1148 (8.1%) DME in the control group. Accounting for underlying DM severity with IPTW, no difference in hazard was seen in the GLP-1RA cohort compared to controls for progression to VTDR (HR = 1.02, 95%CI: 0.92-1.14 p = 0.69), DME (HR = 1.06, 95%CI: 0.95-1.1.9, p = 0.31), or PDR (HR = 0.81, 95%CI: 0.58-1.12, p = 0.20).

CONCLUSION

We found no difference in the risk for vision-threatening diabetic retinopathy, nor for its component diseases, DME or PDR, with GLP-1RA use compared to other oral anti-hyperglycemic agents in patients with NPDR.

Causality between diabetes and membranous nephropathy: Mendelian randomization

BACKGROUND

Membranous nephropathy (MN) has not yet been fully elucidated regarding its relationship with Type I and II Diabetes. This study aims to evaluate the causal effect of multiple types of diabetes and MN by summarizing the evidence from the Mendelian randomization (MR) study.

METHODS

The statistical data for MN was obtained from a GWAS study encompassing 7979 individuals. Regarding diabetes, fasting glucose, fasting insulin, and HbA1C data, we accessed the UK-Biobank, within family GWAS consortium, MAGIC, FinnGen database, MRC-IEU, and Neale Lab, which provided sample sizes ranging from 17,724 to 298,957. As a primary method in this MR analysis, we employed the Inverse Variance Weighted (IVW), Weighted Median, Weighted mode, MR-Egger, Mendelian randomization pleiotropy residual sum, and outlier (MR-PRESSO) and Leave-one-out sensitivity test. Reverse MR analysis was utilized to investigate whether MN affects Diabetes. Meta-analysis was applied to combine study-specific estimates.

RESULTS

It has been determined that type 2 diabetes, gestational diabetes, type 1 diabetes with or without complications, maternal diabetes, and insulin use pose a risk to MN. Based on the genetic prediction, fasting insulin, fasting blood glucose, and HbA1c levels were not associated with the risk of MN. No heterogeneity, horizontal pleiotropy, or reverse causal relationships were found. The meta-analysis results further validated the accuracy.

CONCLUSIONS

The MR analysis revealed the association between MN and various subtypes of diabetes. This study has provided a deeper understanding of the pathogenic mechanisms connecting MN and diabetes.

Incidence and progression of diabetic retinopathy in patients treated with glucagon-like peptide-1 receptor agonists versus sodium-glucose cotransporter 2 inhibitors: A population-based cohort study

AIM

Glucagon-like peptide 1 receptor agonists (GLP1RA) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) are both recommended for patients with diabetes, yet their effects on the development or progression of diabetic retinopathy (DR) are largely unknown.

METHODS

In this retrospective cohort study, data were collected from a nationwide database. Patients with diabetes who initiated treatment with a GLP1RA or SGLT2i between 1 May 2016 and 31 December 2017, were identified. Patients were divided into those with or without a previous diagnosis of DR and then categorized into the GLP1RA and the SGLT2i groups according to drug use. The primary outcome of interest in the DR group was the composite of new-onset proliferative DR, vitreous haemorrhage and tractional retinal detachment (RD). In the non-DR group, the primary outcome was the composite of newly diagnosed DR of any severity, vitreous haemorrhage and RD.

RESULTS

In total, 97 413 patients were identified. After matching, 1517 patients were treated with a GLP1RA and 3034 with an SGLT2i in the DR cohort. In the non-DR cohort, 9549 initiated a GLP1RA and 19 098 initiated an SGLT2i. In patients with pre-existing DR, the incidence of any DR progression event was significantly higher in the GLP1RA group than the SGLT2i group (subdistribution hazard ratio 1.50, 95% confidence interval 1.01-2.23), primarily because of the increased risk of tractional RD. In patients without DR at baseline, the risks of all ocular outcomes were similar between the GLP1RA and SGLT2i groups.

CONCLUSIONS

In patients with diabetes mellitus and established DR, GLP1RA treatment was associated with increased risks of DR progression compared with SGLT2i use.

Comparative Effectiveness of Glucagon-Like Peptide-1 Receptor Agonists, Sodium-Glucose Cotransporter 2 Inhibitors, Dipeptidyl Peptidase-4 Inhibitors, and Sulfonylureas for Sight-Threatening Diabetic Retinopathy

OBJECTIVE

To investigate whether the choice of glucose-lowering agent for type 2 diabetes (T2D) impacts a patient's risk of developing sight-threatening diabetic retinopathy complications.

DESIGN

Retrospective observational database study emulating an idealized target trial.

SUBJECTS

Adult (≥21 years) enrollees in United States commercial, Medicare Advantage, and Medicare fee-for-service plans from January 1, 2014, to December 31, 2021, with T2D and moderate cardiovascular disease (CVD) risk who had no baseline history of advanced diabetic retinal complications, initiating treatment with glucagon-like peptide-1 receptor agonists (GLP-1 RA), sodium-glucose cotransporter 2 inhibitors (SGLT2i), dipeptidyl peptidase-4 inhibitors (DPP-4i), and sulfonylureas.

METHODS

We used inverse propensity scoring weights in time-to-event Cox proportional hazards models.

MAIN OUTCOME MEASURES

Treatment for either diabetic macular edema or proliferative diabetic retinopathy.

RESULTS

The final study population included 371 698 patients, of whom 42 265 initiated GLP-1 RA, 53 476 initiated SGLT2i, 78 444 initiated DPP-4i, and 197 513 initiated sulfonylurea agents. The probability of treatment for sight-threatening retinopathy within 2 and 5 years was 0.3% and 0.7% for patients initiating SGLT2i (median follow-up 830 [interquartile range (IQR), 343-1401] days), 0.4% and 1.0% for GLP-1 RA (669 [IQR, 256-1167] days), 0.4% and 0.9% for DPP-4i (1263 [IQR, 688-1938] days), and 0.5% and 1.2% for sulfonylurea (1223 [IQR, 662-1879] days). Sodium-glucose cotransporter 2 inhibitors use was associated with a lower risk of treatment for sight-threatening retinopathy compared with all other medication classes, including GLP-1 RA (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.55-0.97), DPP-4i (HR, 0.79; 95% CI, 0.64-0.97), and sulfonylurea (HR, 0.61; 95% CI, 0.50-0.74). Glucagon-like peptide-1 receptor agonists use was associated with a similar risk of sight-threatening retinopathy as DPP-4i (HR, 1.07; 95% CI, 0.85-1.35) and sulfonylurea (HR, 0.83; 95% CI, 0.67-1.03).

CONCLUSIONS

Sodium-glucose cotransporter 2 inhibitors use was associated with a lower risk of sight-threatening diabetic retinopathy among adults with T2D and moderate CVD risk compared with other glucose-lowering therapies. Glucagon-like peptide-1 receptor agonists do not confer increased retinal risk, relative to DPP-4i and sulfonylurea medications.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The influence of insulin on diabetic retinopathy and retinal vessel parameters in diabetes

AIM

To investigate the associations between insulin use and diabetic retinopathy (DR), and retinal vascular parameters in type 2 diabetes (T2DM).

METHODS

A total of 6,374 T2DM patients, consisting of 2,231 patients receiving insulin alone and 4143 patients without any hypoglycemic medication, were included in cross-sectional analyses. Among those without DR at baseline, 791 patients were followed for three years in longitudinal analyses. Fundus photography was taken to diagnose DR and calculate central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), arteriolar-to-venular ratio (AVR), and vascular tortuosity. Inverse probability treatment-weighted analyses were performed.

RESULTS

After adjusting for gender, age, body mass index, blood pressure, blood glucose, T2DM duration, smoking, and alcohol use, insulin users showed a higher risk of DR (odds ratio (OR) = 2.27, 95% confidence interval (95%CI) = 2.08-2.48, P < 0.001), larger CRVE (β = 3.92, 95%CI = 2.46-5.37, P < 0.001), smaller AVR (β=-0.0083, 95%CI=-0.0121- -0.0046, P < 0.001), and larger vascular curvature (β = 0.19, 95%CI = 0.05-0.33, P = 0.008). After 3 years, insulin users had a higher risk of developing DR (OR = 1.94; 95% CI = 1.37-2.73, P = 0.002), and greater change in CRVE (β = 3.92, 95%CI = 0.96-6.88, P = 0.009).

CONCLUSIONS

The impact of insulin on the retinal microvasculature provides support for linking insulin to the increased risk of DR, as well as cardiovascular events in T2DM.

Impact of glucagon-like peptide-1 receptor agonists on diabetic retinopathy: A meta-analysis of clinical studies emphasising retinal changes as a primary outcome

BACKGROUND

To determine if glucagon-like peptide-1 receptor agonists (GLP-1RA) are associated with the development and progression of diabetic retinopathy (DR).

METHODS

A systematic search was conducted on PubMed, Cochrane Library, and Embase from inception to February 2024 to identify clinical studies reporting the development of and changes in DR as the primary outcome in patients with type 2 diabetes taking GLP-1RA, insulin, or oral antidiabetic medication (OAD). Two researchers independently completed the search and referred to a third as necessary. Data for meta-analysis was pooled using a random-effects model.

RESULTS

Analysis of seven studies representing 242 537 patients showed a significantly decreased risk of incidence of DR between GLP-1RA and insulin use (RR = 0.66, 95% CI (0.48, 0.91), p = 0.01). There was no difference in the risk of DR complications (e.g., vitreous haemorrhage, retinal detachment, or requiring treatment with intravitreal injections, lasers, vitrectomy). Between GLP-1RA and OAD use, there was no difference in the risk of incidence of DR, while there was a significantly increased risk of DR complications (RR = 1.39, 95% CI (1.07, 1.80), p = 0.01).

CONCLUSION

Our findings indicate no elevated risk of incidence of DR linked to GLP-1RA compared to insulin. In fact, GLP-1RA may offer potential advantages over insulin regarding the overall incidence of DR. The increased risk of DR requiring treatment and associated complications in the GLP-1RA group compared to OAD may be due to the transient progression of DR associated with a rapid decrease in HbA1c - a phenomenon not specific to GLP-1RA and warrants further investigation.

Assessing the therapeutic and toxicological profile of novel GLP-1 receptor agonists for type 2 diabetes

INTRODUCTION

GLP-1 receptor agonists provide multiple benefits for patients with type 2 diabetes. Nonetheless, there are also several significant adverse effects associated with these agents. A thorough understanding of both therapeutic and toxicological profiles of GLP-1 receptor agonists is crucial for appropriate utilization of this medication class. A literature search of PubMed and ClinicalTrials.gov was carried out to inform discussion on the topic.

AREAS COVERED

This review article discusses the key advantages and disadvantages derived from the use of GLP-1 receptor agonists in the treatment of type 2 diabetes. Landmark trials which helped characterize the cardiovascular and renal benefits of GLP-1 receptor agonists are highlighted. We also discuss key studies still in progress and new formulations under investigation.

EXPERT OPINION

GLP-1 receptor agonists provide glycemic and complication-risk reduction benefits for individuals with type 2 diabetes. Current data suggests there is a lot of potential for further applications, even outside of type 2 diabetes management. It would be of particular interest to see the range of benefits conferred from GLP-1 receptor agonists in individuals without type 2 diabetes. Broader application of these medications could be expected given the ongoing development of new oral formulations and combination agents.

Association of continuous subcutaneous insulin therapy and diabetic retinopathy in type 1 diabetes: A national cohort study

AIM

This study aimed to investigate the short-and long-term effect on diabetic retinopathy (DR) in individuals with type 1 diabetes treated with continuous subcutaneous insulin injections (CSII) compared to those using multiple daily injections (MDI).

METHODS

We conducted a register-based matched cohort study utilizing data from the Danish Registry of Diabetic Retinopathy as well as several other national Danish health registers. Our cohort consisted of all individuals with type 1 diabetes who attended the Danish screening program for DR from 2013 to 2022. We included individuals registered with CSII treatment, and compared them to individuals using MDI, matched by age, sex, and DR level. Cox regression analysis was performed to evaluate the outcomes.

RESULTS

The study included 674 individuals treated with CSII and 2006 matched MDI users. In our cohort 53.4 % were female and median age was 36 (IQR 27-47). Average follow-up risk-time was 4.8 years. There was no difference in the risk of DR worsening between the CSII group and MDI group (HR 1.05 [95%CI 0.91; 1.22], p = 0.49). However, an increased risk of focal photocoagulation was observed in the CSII group (HR 2.40 [95%CI 1.11; 5.19], p = 0.03).

CONCLUSIONS

Our findings indicate that CSII treatment does not confer a significant difference in the overall short- and long-term risk of DR worsening or ocular intervention compared to MDI treatment. These results provide insights into the DR outcomes of CSII treatment in individuals with type 1 diabetes.

Incidence and Progression of Diabetic Retinopathy After Cataract Surgery: A Systematic Review and Meta-Analysis

PURPOSE

The impact of cataract surgery on diabetic retinopathy (DR) in patients with diabetes mellitus (DM) remains uncertain. This study aimed to investigate the incidence and progression of DR in patients with DM who underwent cataract surgery.

DESIGN

Meta-analysis.

METHODS

A systematic search of PubMed, Cochrane CENTRAL, and Embase databases was conducted from inception to April 2024. Randomized controlled trials or observational cohort studies involving adult patients with DM who underwent cataract surgery were included. Studies reporting data on the incidence or progression of postoperative DR were considered. Effect sizes were determined using risk ratios (RRs) with 95% confidence intervals (CIs), and meta-analysis was performed using a random-effects model. Subgroup analysis and meta-regression were conducted on perioperative demographic factors such as types of cataract surgery, DM durations, preoperative glycated hemoglobin A1c levels, and postoperative follow-up durations.

RESULTS

Data from 15 studies, involving 7,287 patients were analyzed. Postoperative DR incidence was elevated compared to the control group (RR, 1.38; 95% CI: 1.16-1.63; P < .001), although not significantly different in paired studies (RR, 0.85; 95% CI: 0.39-1.83; P = .671). DR progression was significantly higher after cataract surgery (RR, 1.46; 95% CI: 1.28-1.66; P < .001), irrespective of cataract surgery type and study design. Our analysis also revealed a significant increase in DR progression to sight-threatening DR, which includes clinically significant macular edema and proliferative diabetic retinopathy, following cataract surgery (RR, 1.84; 95% CI: 1.21-2.81; P = .005). Additionally, various risk factors such as preoperative HbA1c level, duration of postoperative follow-up, duration of diabetic diagnosis, age, and use of insulin therapy were investigated, However, none of these parameters significantly influenced the incidence or progression of postoperative DR.

CONCLUSIONS

Further research is needed to fully understand the incidence of DR after cataract surgery. However, our study provides moderate evidence supporting the progression of DR following such surgical interventions. Therefore, it is imperative to closely monitor DR progression within one year following cataract surgery in patients with DM.

Artificial intelligence in individualized retinal disease management

Owing to the rapid development of modern computer technologies, artificial intelligence (AI) has emerged as an essential instrument for intelligent analysis across a range of fields. AI has been proven to be highly effective in ophthalmology, where it is frequently used for identifying, diagnosing, and typing retinal diseases. An increasing number of researchers have begun to comprehensively map patients' retinal diseases using AI, which has made individualized clinical prediction and treatment possible. These include prognostic improvement, risk prediction, progression assessment, and interventional therapies for retinal diseases. Researchers have used a range of input data methods to increase the accuracy and dependability of the results, including the use of tabular, textual, or image-based input data. They also combined the analyses of multiple types of input data. To give ophthalmologists access to precise, individualized, and high-quality treatment strategies that will further optimize treatment outcomes, this review summarizes the latest findings in AI research related to the prediction and guidance of clinical diagnosis and treatment of retinal diseases.

Disability-related disparities in health outcomes among newly diagnosed diabetic patients: A retrospective cohort

BACKGROUND

A distinct gap in the literature persists regarding the health outcome of individuals with Type 2 diabetes who also have disabilities. This study aimed to investigate potential disparities in events occurrence among diabetes patients across various disability stages.

METHODS

We conducted a retrospective cohort study on patients newly diagnosed with diabetes in 2013 and 2014, aged ≥ 18 years, and followed them until December 2021, using data from the Korean National Health Insurance database. All-cause mortality and hospitalization for diabetes mellitus and cardio-cerebrovascular diseases (CVD) was assessed.

RESULTS

The study included 26,085 patients, encompassing individuals without disabilities and those with physical, visual, hearing and speech, intellectual and developmental, and mental disabilities. After adjustment, individuals with disabilities had a higher risk of all-cause death (adjusted hazard ratio [aHR]: 1.25, 95% CI: 1.07-1.48) compared to those without disabilities. In particular, severe disabilities and hearing and speech disabilities showed significantly higher risks of all-cause death (aHR: 1.40, 95% CI: 1.06-1.85 and aHR: 1.58, 95% CI: 1.17-2.15, respectively), with marginal significance for mild disabilities (aHR: 1.20, 95% CI: 0.99-1.45) and mental disorders (aHR: 1.92, 95% CI: 0.98-3.73). Patients with disabilities also had significantly increased risks of CVD-related first admissions (aHR: 1.30, 95% CI: 1.07-1.56) and diabetes-related first admissions (aHR: 1.31, 95% CI: 1.20-1.43) compared to those without disabilities.

CONCLUSIONS

This study underscores the urgent need for public health policies to prioritize individuals with disabilities and diabetes, addressing the disparities in health outcome.

Glucagon-like Peptide 1 Receptor Agonist use and the effect on diabetic retinopathy: An uncertain relationship

Glucagon-like Peptide 1 Receptor Agonists (GLP-1 RAs) are a group of relatively novel medications for the treatment of diabetes mellitus. These medications can mimic the naturally occurring incretins of the body, which promote the release of insulin in response to hyperglycaemia. The anti-glycaemic effects of these medications can be profound and carry other metabolic benefits such as promoting weight loss. Clinical trials have shown GLP-1 RAs are safe to use from a cardiovascular perspective. However, some trials have suggested a link between GLP-1 RA use and worsening diabetic retinopathy. The conclusions surrounding this link are poorly established as data is drawn primarily from cardiovascular outcome trials. If an association does exist, a possible explanation might be the observed phenomenon of early worsening diabetic retinopathy with rapid correction of hyperglycaemic states. Trials which look at diabetic retinopathy as a primary outcome in relation to use of GLP-1 RAs are sparse and warrant investigation given the growing use of this group of medications. Therefore currently, it is uncertain what effect, beneficial or adverse, GLP-1 RA use has on diabetic retinopathy. This article provides an overview of GLP-1 RA use as a treatment for diabetes mellitus and the current understanding of their relationship with diabetic retinopathy.

Drug Exposure As a Predictor in Diabetic Retinopathy Risk Prediction Models-A Systematic Review and Meta-Analysis

PURPOSE

To conduct a systematic review to assess drug exposure handling in diabetic retinopathy (DR) risk prediction models, a network-meta-analysis to identify drugs associated with DR and a meta-analysis to determine which drugs contributed to enhanced model performance.

DESIGN

Systematic review and meta-analysis.

METHODS

We included studies presenting DR models incorporating drug exposure as a predictor. We searched EMBASE, MEDLINE, and SCOPUS from inception to December 2023. We evaluated the quality of studies using the Prediction model Risk of Bias Assessment Tool and certainty using GRADE. We conducted network meta-analysis and meta-analysis to estimate the odds ratio (OR) and pooled C-statistic, respectively, and 95% confidence intervals (CI) (PROSPERO: CRD42022349764).

RESULTS

Of 5,653 records identified, we included 28 studies of 678,837 type 1 or 2 diabetes participants, of which 38,579 (5.7%) had DR. A total of 19, 3, and 7 studies were at high, unclear, and low risk of bias, respectively. Drugs included in models as predictors were: insulin (n = 24), antihypertensives (n = 5), oral antidiabetics (n = 12), lipid-lowering drugs (n = 7), antiplatelets (n = 2). Drug exposure was modelled primarily as a categorical variable (n = 23 studies). Two studies handled drug exposure as time-varying covariates, and one as a time-dependent covariate. Insulin was associated with an increased risk of DR (OR = 2.50; 95% CI: 1.61-3.86). Models that included insulin (n = 9) had a higher pooled C-statistic (C-statistic = 0.84, CI: 0.80-0.88), compared to models (n = 9) that incorporated a combination of drugs alongside insulin (C-statistic = 0.79, CI: 0.74-0.84), as well as models (n = 3) not including insulin (C-statistic = 0.70, CI: 0.64-0.75). Limitations include the high risk of bias and significant heterogeneity in reviewed studies.

CONCLUSION

This is the first review assessing drug exposure handling in DR prediction models. Drug exposure was primarily modelled as a categorical variable, with insulin associated with improved model performance. However, due to suboptimal drug handling, associations between other drugs and model performance may have been overlooked. This review proposes the following for future DR prediction models: (1) evaluation of drug exposure as a variable, (2) use of time-varying methodologies, and (3) consideration of drug regimen details. Improving drug exposure handling could potentially unveil novel variables capable of significantly enhancing the predictive capability of prediction models.

Resilience to diabetic retinopathy

Chronic elevation of blood glucose at first causes relatively minor changes to the neural and vascular components of the retina. As the duration of hyperglycemia persists, the nature and extent of damage increases and becomes readily detectable. While this second, overt manifestation of diabetic retinopathy (DR) has been studied extensively, what prevents maximal damage from the very start of hyperglycemia remains largely unexplored. Recent studies indicate that diabetes (DM) engages mitochondria-based defense during the retinopathy-resistant phase, and thereby enables the retina to remain healthy in the face of hyperglycemia. Such resilience is transient, and its deterioration results in progressive accumulation of retinal damage. The concepts that co-emerge with these discoveries set the stage for novel intellectual and therapeutic opportunities within the DR field. Identification of biomarkers and mediators of protection from DM-mediated damage will enable development of resilience-based therapies that will indefinitely delay the onset of DR.

Melatonin: Unveiling the functions and implications in ocular health

Melatonin, a versatile hormone produced by the pineal gland, has garnered considerable scientific interest due to its diverse functions. In the eye, melatonin regulates a variety of key processes like inhibiting angiogenesis by reducing vascular endothelial growth factor levels and protecting the blood-retinal barrier (BRB) integrity by enhancing tight junction proteins and pericyte coverage. Melatonin also maintains cell health by modulating autophagy via the Sirt1/mTOR pathways, reduces inflammation, promotes antioxidant enzyme activity, and regulates intraocular pressure fluctuations. Additionally, melatonin protects retinal ganglion cells by modulating aging and inflammatory pathways. Understanding melatonin's multifaceted functions in ocular health could expand the knowledge of ocular pathogenesis, and shed new light on therapeutic approaches in ocular diseases. In this review, we summarize the current evidence of ocular functions and therapeutic potential of melatonin and describe its roles in angiogenesis, BRB integrity maintenance, and modulation of various eye diseases, which leads to a conclusion that melatonin holds promising treatment potential for a wide range of ocular health conditions.

Role of Systemic Factors in Improving the Prognosis of Diabetic Retinal Disease and Predicting Response to Diabetic Retinopathy Treatment

Topic

To review clinical evidence on systemic factors that might be relevant to update diabetic retinal disease (DRD) staging systems, including prediction of DRD onset, progression, and response to treatment.

Clinical relevance

Systemic factors may improve new staging systems for DRD to better assess risk of disease worsening and predict response to therapy.

Methods

The Systemic Health Working Group of the Mary Tyler Moore Vision Initiative reviewed systemic factors individually and in multivariate models for prediction of DRD onset or progression (i.e., prognosis) or response to treatments (prediction).

Results

There was consistent evidence for associations of longer diabetes duration, higher glycosylated hemoglobin (HbA1c), and male sex with DRD onset and progression. There is strong trial evidence for the effect of reducing HbA1c and reducing DRD progression. There is strong evidence that higher blood pressure (BP) is a risk factor for DRD incidence and for progression. Pregnancy has been consistently reported to be associated with worsening of DRD but recent studies reflecting modern care standards are lacking. In studies examining multivariate prognostic models of DRD onset, HbA1c and diabetes duration were consistently retained as significant predictors of DRD onset. There was evidence of associations of BP and sex with DRD onset. In multivariate prognostic models examining DRD progression, retinal measures were consistently found to be a significant predictor of DRD with little evidence of any useful marginal increment in prognostic information with the inclusion of systemic risk factor data apart from retinal image data in multivariate models. For predicting the impact of treatment, although there are small studies that quantify prognostic information based on imaging data alone or systemic factors alone, there are currently no large studies that quantify marginal prognostic information within a multivariate model, including both imaging and systemic factors.

Conclusion

With standard imaging techniques and ways of processing images rapidly evolving, an international network of centers is needed to routinely capture systemic health factors simultaneously to retinal images so that gains in prediction increment may be precisely quantified to determine the usefulness of various health factors in the prognosis of DRD and prediction of response to treatment.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Assessing the importance of risk factors for diabetic retinopathy in patients with type 2 diabetes mellitus: Results from the classification and regression tree models

BACKGROUND

Diabetic retinopathy (DR) is one of the serious complications of diabetes mellitus (DM). Many studies have identified the risk factors associated with DR, but there is not much evidence on the importance of these factors for DR. This study aimed to investigate the associated factors for patients with type 2 DM (T2DM) and calculate the importance of the identified factors.

MATERIALS AND METHODS

Using probability proportionate to size sampling method in this community-based cross-sectional study, 22 community health service centers were selected from 10 administrative districts in Shenzhen, China. Approximately 60 T2DM patients were recruited from each center. The participants completed a structural questionnaire, had their venous blood collected, and underwent medical examinations and fundus photography. Logistic regression models were used to identify the risk factors of DR. The classification and regression tree (CART) model was used to calculate the importance of the identified risk factors.

RESULTS

This study recruited 1097 T2DM patients, 266 of whom were identified as having DR, yielding a prevalence rate of 24.3% (95% confidence interval [CI]: 21.7%-26.9%). Results showed that a longer duration of DM, indoor-type lifestyle, and higher levels of hemoglobin A1c (HbA1c) or urea increased the risk of DR. Patients with HbA1c values ≥7% were about 2.45 times (odds ratio: 2.45; 95% CI: 1.83-3.29) more likely to have DR than their counterparts. The CART model found that the values of variable importance for HbA1c, DM duration, lifestyle (i.e., indoor type), and urea were 48%, 37%, 10%, and 4%, respectively.

CONCLUSION

The prevalence of DR is high for T2DM patients who receive DM health management services from the primary healthcare system. HbA1c is the most important risk factor for DR. Integration of DR screening and HbA1c testing into the healthcare services for T2DM to reduce vision impairment and blindness is urgently warranted.

Impact of treatment cessation on incidence and progression of retinopathy in Japanese patients with type 2 diabetes mellitus: a retrospective cohort study

Aims

This cohort study investigated the association between treatment cessation and incidence/progression of diabetic retinopathy (DR) in Japanese patients with type 2 diabetes mellitus (T2DM).

Materials and methods

Data were extracted from electronic medical records at the University of the Ryukyu Hospital and the Tomishiro Central Hospital of Okinawa, Japan. We enrolled 417 diabetic patients without DR (N = 281) and with nonproliferative DR (N = 136) at the baseline. Treatment cessation was defined as failing to attend outpatient clinics for at least twelve months prior to the baseline. After a median follow-up of 7 years, we compared the incidence/progression rate of DR including nonproliferative and proliferative DR between patients with and without treatment cessation and calculated the odds ratio (OR) in the treatment cessation group using a logistic regression model.

Results

The overall prevalence of treatment cessation was 13% in patients with T2DM. Characteristics of treatment cessation included relative youth (57 ± 11 years vs. 63 ± 12 years, P < 0.01). Treatment cessation was tightly associated with the incidence of DR (OR 4.20 [95% confidence interval [CI] 1.46-12.04, P < 0.01) and also incidence/progression of DR (OR 2.70 [1.28-5.69], P < 0.01), even after adjusting for age, sex, BMI, duration of T2DM, and HbA1c level.

Conclusions

By considering major confounding factors, the present study demonstrates an independent association between treatment cessation and incidence of DR in patients with T2DM, highlighting treatment cessation as an independent risk for DR in T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-024-00724-7.

Prevention and treatment of ischaemic and haemorrhagic stroke in people with diabetes mellitus: a focus on glucose control and comorbidities

Diabetes mellitus is a significant risk factor for both ischaemic and haemorrhagic stroke, affecting up to a third of individuals with cerebrovascular diseases. Beyond being a risk factor for stroke, diabetes and hyperglycaemia have a negative impact on outcomes after ischaemic and haemorrhagic stroke. Hyperglycaemia during the acute ischaemic stroke phase is associated with a higher risk of haemorrhagic transformation and poor functional outcome, with evidence in favour of early intervention to limit and manage severe hyperglycaemia. Similarly, intensive glucose control nested in a broader bundle of care, including blood pressure, coagulation and temperature control, can provide substantial benefit for clinical outcomes after haemorrhagic stroke. As micro- and macrovascular complications are frequent in people with diabetes, cardiovascular prevention strategies also need to consider tailored treatment. In this regard, the broader availability of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists can allow tailored treatments, particularly for those with heart failure and chronic kidney disease as comorbidities. Here, we review the main concepts of hyperacute stroke management and CVD prevention among people with diabetes, capitalising on results from large studies and RCTs to inform clinicians on preferred treatments.

Existing and emerging GLP-1 receptor agonist therapy: Ramifications for diabetic retinopathy screening

GLP-1 receptor agonist treatment revolutionised the management of type 2 diabetes mellitus with significant enhancement of cardiovascular risk reduction. They have been instrumental in effectively managing the glycaemic control of this at-risk patient group. This class of drugs are associated with rapid improvement in glucose levels and consequently, transient early worsening of pre-existing diabetic retinopathy (DR) which is well-recognised, but this paradox is less commonly perceived in routine clinical practice. The recent shortage of supply has resulted in an enforced hiatus to prescribing all existing GLP-1 receptor agonists, which is expected to last all through 2024. This becomes even more pertinent as their DR could have progressed due to worsening HbA1c as a result of the unforeseen interruption to GLP-1 receptor agonist treatment. Therefore, when these medications are recommenced in a few months' time, all prescribers need to be aware of these patients' most up-to-date DR status and liaise with their affiliated screening service.

Evaluation of systemic medications associated with diabetic retinopathy: a nested case-control study from the UK Biobank

AIMS

This study aims to investigate the associations between commonly used systemic medications and diabetic retinopathy (DR).

METHODS

Individuals with linked primary care prescription data from the UK Biobank were included. Cases were defined as individuals with a Hospital Episode Statistics-coded or primary care recorded diagnosis of DR or self-reported DR. Controls were matched for age, sex, glycosylated haemoglobin, duration of diabetes mellitus (DM), hypertension status and cardiovascular disease status. ORs and 95% CIs were calculated using conditional univariate and multivariable logistic regression models.

RESULTS

A total of 3377 case subjects with DR were included in the study and matched with 3377 control subjects. In multivariable logistic regression, increased odds of incident DR were observed for exposure to short-acting insulins (OR 1.63; 95% CI 1.22 to 2.18), medium-acting insulins (OR 2.10; 95% CI 1.60 to 2.75), sulfonylureas (OR 1.30; 95% CI 1.16 to 1.46). Instead, the use of fibrates (OR 0.71; 95% CI 0.53 to 0.94) and Cox-2 inhibitors (OR 0.68; 95% CI 0.58 to 0.79) was associated with decreased odds of incident DR. Dose-response relationships were observed for all five drug categories (all p<0.05).

CONCLUSIONS

This study comprehensively investigated the associations between systemic medication use and DR and found significant associations between the use of short-acting insulins, medium-acting insulins and sulfonylureas with increased odds of incident DR. In contrast, fibrates and Cox-2 inhibitors were associated with decreased odds of incident DR. These findings may provide valuable insights into DM medication management and serve as a reference for the prevention of DR in patients with DM.

Therapeutic Effects of Anti-Inflammatory and Anti-Oxidant Nutritional Supplementation in Retinal Ischemic Diseases

Appropriate nutrients are essential for cellular function. Dietary components can alter the risk of systemic metabolic diseases, including cardiovascular diseases, cancer, diabetes, and obesity, and can also affect retinal diseases, including age-related macular degeneration, diabetic retinopathy, and glaucoma. Dietary nutrients have been assessed for the prevention or treatment of retinal ischemic diseases and the diseases of aging. In this article, we review clinical and experimental evidence concerning the potential of some nutritional supplements to prevent or treat retinal ischemic diseases and provide further insights into the therapeutic effects of nutritional supplementation on retinopathies. We will review the roles of nutrients in preventing or protecting against retinal ischemic diseases.

Update on diabetic retinopathy during pregnancy

Diabetes mellitus (DM) leads to several vascular and neurological complications, including diabetic retinopathy (DR). As the population ages, health problems in certain groups, including children and pregnant women, are drawing more and more attention. Pregnancy is one of the independent risk factors for the development and progression of DR. Pregnancy-induced changes may contribute to or worsen DR, which can cause a tremendous burden on public health. It is essential for pregnant women with DR and their offspring to minimize the risk of vision loss from DR in this population and adverse outcomes by understanding the development and processes behind this process. Thus, we have updated the recent situation of epidemiology, evolution characteristics, risk factors, pathophysiology, pregnancy outcomes for a better understanding of the latest status of DR, helping to improve maternal and neonatal pregnancy outcomes, and promoting health for women with DR.

Weight loss, bariatric surgery, and novel antidiabetic drugs effects on diabetic retinopathy: a review

PURPOSE OF REVIEW

Diabetic retinopathy (DR) is a leading cause of visual impairment, and the increasing prevalence of diabetes and obesity will impact rates of visual impairment moving forward. Our review aims to synthesize the current body of evidence regarding the impact of lifestyle interventions, such as weight loss, bariatric surgery, and novel antidiabetic drugs, on DR.

RECENT FINDINGS

Literature review revealed insufficient evidence regarding the impact of weight loss on DR. Preoperative DR patients undergoing bariatric surgery were found to have similar short-term chances of improvement or worsening DR. Progression of DR with glucagon-like peptide 1 receptor agonists treatments appears unrelated to specific drugs and was also observed with traditional antidiabetic medications.

SUMMARY

Rapidly correcting HbA1c levels (≥2%) can paradoxically lead to early worsening DR. Patients considering weight loss, bariatric surgery, and novel antidiabetic drugs should be aware of the potential for DR progression, but they should not be discouraged, as achieving glycemic control is essential for reducing long-term morbidity and mortality from other diabetes-related complications. It is advisable to conduct a baseline retinal examination before treatment and continue monitoring during therapy. Further research is needed to understand the long-term effects of these treatments on DR.

Drp1-dependent mitochondrial fragmentation mediates photoreceptor abnormalities in type 1 diabetic retina

Recent studies have highlighted that retinal neurodegeneration precedes microvascular changes in diabetic retinopathy (DR), but the specific mechanisms remain unclear. Given the pivotal role of dysfunctional mitochondria and oxidative stress in early DR, our objective was to observe mitochondria-related alterations in the neural retina of type one diabetic mellitus mice with no evidence of DR (T1DM-NDR). We aimed to identify the key mitochondrial-related proteins contributing to mitochondrial injury. Our study revealed that T1DM-NDR mice exhibited outer retina thinning, including the ellipsoid zone, inner segment, and outer segment. Additionally, there was an impaired amplitude of the b-wave in electroretinogram (ERG) and a disorganized arrangement of the photoreceptor layer. In both the retina of DM mice and high glucose (HG)-treated 661w cells, mitochondria appeared swollen and fragmented, with disrupted cristae, disorganized or shortened branches in the mitochondrial network, and decreased mitochondrial membrane potential. Among the mitochondrial-related proteins, dynamin-related protein 1 (Drp1) was upregulated, and the ratio of phosphorylated Drp1 protein at serine 616 (S616) and serine 637 (S637) sites significantly increased in the retina of DM mice. The administration of Mdivi-1 ameliorated high-glucose-induced dysfunctional mitochondria, thereby protecting T1DM-NDR mice retina from morphological and functional injuries. Our findings suggest that hyperglycemia promotes Drp1-mediated mitochondrial dysfunction, which may be a significant factor in the development of DR. The inhibition of high-glucose-induced mitochondrial fission emerges as a potential and innovative intervention strategy for preventing DR.

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.

Association between obstructive coronary disease and diabetic retinopathy: Cross-sectional study of coronary angiotomography and multimodal retinal imaging

AIMS

To investigate the association between diabetic retinopathy (DR) and coronary artery disease (CAD) using coronary angiotomography (CCTA) and multimodal retinal imaging (MMRI) with ultra-widefield retinography and optical coherence tomography angiography and structural domain.

METHODS

Single-center, cross-sectional, single-blind. Patients with diabetes who had undergone CCTA underwent MMRI. Uni and multivariate analysis were used to assess the association between CAD and DR and to identify variables independently associated with DR.

RESULTS

We included 171 patients, 87 CAD and 84 non-CAD. Most CAD patients were males (74 % vs 38 %, P < 0.01), insulin users (52 % vs 38 %, p < 0.01) and revascularized (64 %). They had a higher prevalence of DR (48 % vs 22 %, p = 0.01), microaneurysms (25 % vs 13 %, p = 0.04), intraretinal cysts (22 % vs 8 %, p = 0.01) and areas of reduced capillary density (46 % vs 20 %, p < 0.01). CAD patients also had lower mean vascular density (MVD) (15.7 % vs 16.5,%, p = 0.049) and foveal avascular zone (FAZ) circularity (0.64 ± 0.1 vs 0.69 ± 0.1, p = 0.04). There were significant and negative correlations between Duke coronary score and MVD (r = -0.189; p = 0.03) and FAZ circularity (r = -0,206; p = 0.02). CAD, DM duration and insulin use independently associated with DR.

CONCLUSIONS

CAD patients had higher prevalence of DR and lower MVD. CAD, DM duration and insulin use were independently associated with DR.

Acute worsening of microvascular complications of diabetes mellitus during rapid glycemic control: The pathobiology and therapeutic implications

While chronic hyperglycaemia resulting from poorly controlled diabetes mellitus (DM) is a well-known precursor to complications such as diabetic retinopathy, neuropathy (including autonomic neuropathy), and nephropathy, a paradoxical intensification of these complications can rarely occur with aggressive glycemic management resulting in a rapid reduction of glycated haemoglobin. Although, acute onset or worsening of retinopathy and treatment induced neuropathy of diabetes are more common among these complications, rarely other problems such as albuminuria, diabetic kidney disease, Charcot's neuroarthropathy, gastroparesis, and urinary bladder dysfunction are also encountered. The World Journal of Diabetes recently published a rare case of all these complications, occurring in a young type 1 diabetic female intensely managed during pregnancy, as a case report by Huret et al. It is essential to have a comprehensive understanding of the pathobiology, prevalence, predisposing factors, and management strategies for acute onset, or worsening of microvascular complications when rapid glycemic control is achieved, which serves to alleviate patient morbidity, enhance disease management compliance, and possibly to avoid medico-legal issues around this rare clinical problem. This editorial delves into the dynamics surrounding the acute exacerbation of microvascular complications in poorly controlled DM during rapid glycaemic control.

Sight threatening diabetic retinopathy in patients with macular telangiectasia type 2

PURPOSE

Although diabetes is highly prevalent in patients with MacTel, progression to severe non-proliferative (NPDR) and proliferative diabetic retinopathy (PDR) is rarely reported. We report multimodal imaging features of sight-threatening diabetic retinopathy (STDR) in eyes with macular telangiectasia type 2 (MacTel).

METHODS

Retrospective case series of seven participants of the MacTel Study at the Moorfields Eye Hospital NHS Foundation Trust study site and one patient from the Institute of Retina and Vitreous of Londrina, Brazil. Sight threatening diabetic retinopathy was defined as severe NPDR, PDR or diabetic macular edema.

RESULTS

We report imaging features of 16 eyes of eight patients (7/8, 87.5% female) with diagnoses of MacTel and type 2 diabetes mellitus with STDR. Mean (SD) age was 56 (8.3) years. Patients were followed-up for a mean time of 9.1 (4.7) years. A total of 10/16 (62.5%) eyes showed PDR and 2/16 (12.5%) eyes presented a macular epiretinal neovascularization.

CONCLUSIONS

People with diabetes mellitus and MacTel may not be protected from STDR as previously reported. Although the two diseases rarely co-exist, regular monitoring for diabetic retinopathy progression is recommended according to baseline retinopathy severity grades in line with established international guidelines. The presence of MacTel may not modify extended screening intervals, but there is no current evidence. The limited case series in the literature support treatment for complications and should follow the standard of care for either condition. Due to dual pathology, reactivation may be difficult to diagnose on standard imaging and multimodal imaging is recommended.

Acute and Chronic Adverse Outcomes of Type 1 Diabetes

Type 1 diabetes is associated with both acute and chronic complications. Acute complications include diabetic ketoacidosis and severe hypoglycemia. Chronic complications can be microvascular or macrovascular. Microvascular complications include retinopathy, nephropathy, and neuropathy. The pathophysiology of microvascular complications is complex. Hyperglycemia is a common underlying risk factor, underscoring the importance of optimizing glycemic management. Patients with type 1 diabetes are also at increased risk of macrovascular complications including coronary artery disease and vascular disease. The American Diabetes Association provides screening guidelines for chronic complications of diabetes. Adherence to these guidelines is an important aspect of diabetes care.

Shedding light on eye disease in obesity: A review

Obesity is known to be associated with numerous ocular manifestations, including but not limited to, diabetic retinopathy (DR), age-related macular degeneration (AMD), cataracts, glaucoma, and dry eye disease. This review aims to provide an overview of the ophthalmological findings in obesity. A literature search was conducted using PubMed and Cochrane databases for studies describing randomized clinical trials, meta-analyses, systematic reviews, and observational studies published from 1 January 2017 to 1 April 2023. The search terms used included relevant keywords such as 'obesity', 'body mass index', 'waist-to-hip ratio', 'bariatric', 'ophthalmology', 'eye disease', 'myopia', 'retinopathy', 'glaucoma', and 'cataract'. This literature search was performed on 1 April 2023. Obesity is associated with increased risk of developing DR, a sight-threatening complication of diabetes mellitus. Similarly, obesity has been shown to increase risk of AMD, cataracts, glaucoma, and ocular surface disease. Multiple mechanisms linking obesity to ophthalmic disease have been proposed. Adipose tissue produces various inflammatory cytokines that can affect ocular tissues, leading to disease progression. Additionally, obesity is associated with systemic metabolic changes that can influence ocular health. Bariatric surgery has been shown to be protective against development of ophthalmic disease. Obesity is a significant risk factor for several ophthalmological diseases. Healthcare providers should encourage weight loss in patients with overweight or obesity to prevent or delay the onset of ocular complications. Further research is needed to better understand the underlying mechanisms of this association, and to identify effective strategies for preventing or managing ophthalmic disease in patients with obesity.

Association of sodium-glucose cotransporter-2 inhibitors and the risk of retinal vascular occlusion: A real-world retrospective cohort study in Taiwan

AIMS

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are proposed to alleviate the development of inflammatory eye diseases. However, the association between SGLT2i and retinal vascular occlusion remains unclear. Therefore, this study aims to explore the effects of SGLT2i on the incidence of retinal vascular occlusion.

MATERIALS AND METHODS

This retrospective cohort study analysed electronic medical records data from the largest multi-institutional database in Taiwan. Individuals who initiated SGLT2is and dipeptidyl peptidase 4 inhibitors (DPP4is) between 2016 and 2019 were included in our analysis. To conduct a homogenous comparison, inverse probability of treatment weighting with propensity scoring was employed. The primary outcome was retinal vascular occlusion, and the secondary outcomes were retinal vascular occlusion-related complications (macular oedema, vitreous haemorrhage, and tractional retinal detachment) and conditions requiring vitreoretinal intervention (intravitreal injection, retinal laser therapy, and vitrectomy).

RESULTS

In total, 12,074 SGLT2i users and 39,318 DPP4i users were included. The incidence rate of retinal vascular occlusion in the SGLT2i and DPP4i groups was 1.2 (95% confidence interval [CI], 0.9-1.4) and 1.6 (95% CI, 1.3-1.8) events per 1000 person-years, respectively, which yielded a subdistribution hazard ratio (SHR) of 0.74 (95% CI, 0.55-0.99). Similar risk reductions were observed in the retinal vascular occlusion-related complications (SHR, 0.76; 95% CI, 0.69-0.84) and conditions requiring vitreoretinal intervention (SHR, 0.84; 95% CI, 0.77-0.94).

CONCLUSIONS

In this multi-institutional study in Taiwan, SGLT2i use was associated with a reduced risk of retinal vascular occlusion. Further prospective studies are required to ascertain this association.

PACE: randomized, controlled, multicentre, multinational, phase III study of PLX-PAD for critical limb ischaemia in patients unsuitable for revascularization: randomized clinical trial

BACKGROUND

Revascularization is the primary treatment modality for chronic limb-threatening ischaemia (CLTI), but is not feasible in all patients. PLX-PAD is an off-the-shelf, placental-derived, mesenchymal stromal cell-like cell therapy. This study aimed to evaluate whether PLX-PAD would increase amputation-free survival in people with CLTI who were not candidates for revascularization.

METHODS

People with CLTI and minor tissue loss (Rutherford 5) who were unsuitable for revascularization were entered into a randomized, parallel-group, placebo-controlled, multinational, blinded, trial, in which PLX-PAD was compared with placebo (2 : 1 randomization), with 30 intramuscular injections (0.5 ml each) into the index leg on days 0 and 60. Planned follow-up was 12-36 months, and included vital status, amputations, lesion size, pain and quality-of-life assessments, haemodynamic parameters, and adverse events.

RESULTS

Of 213 patients enrolled, 143 were randomized to PLX-PAD and 70 to placebo. Demographics and baseline characteristics were balanced. Most patients were Caucasian (96.2%), male (76.1%), and ambulatory (85.9%). Most patients (76.6%) reported at least one adverse event, which were mostly expected events in CLTI, such as skin ulcer or gangrene. The probability of major amputation or death was similar for placebo and PLX-PAD (33 and 28.6% respectively; HR 0.93, 95% c.i. 0.53 to 1.63; P = 0.788). Revascularization and complete wound healing rates were similar in the two groups. A post hoc analysis of a subpopulation of 121 patients with a baseline haemoglobin A1c level below 6.5% showed improved 12-month amputation-free survival (HR 0.46, 0.21 to 0.99; P = 0.048).

CONCLUSION

Although there was no evidence that PLX-PAD reduced amputation-free survival in the entire study population, benefit was observed in patients without diabetes mellitus or whose diabetes was well controlled; this requires confirmation in further studies. Trial registration: NCT03006770 (http://www.clinicaltrials.gov); 2015-005532-18 (EudraCT Clinical Trials register - Search for 2015-005532-18).

Associations of antidiabetic drugs with diabetic retinopathy in people with type 2 diabetes: an umbrella review and meta-analysis

Background

Diabetic retinopathy (DR) is the most frequent complication of type 2 diabetes and remains the leading cause of preventable blindness. Current clinical decisions regarding the administration of antidiabetic drugs do not sufficiently incorporate the risk of DR due to the inconclusive evidence from preceding meta-analyses. This umbrella review aimed to systematically evaluate the effects of antidiabetic drugs on DR in people with type 2 diabetes.

Methods

A systematic literature search was undertaken in Medline, Embase, and the Cochrane Library (from inception till 17th May 2022) without language restrictions to identify systematic reviews and meta-analyses of randomized controlled trials or longitudinal studies that examined the association between antidiabetic drugs and DR in people with type 2 diabetes. Two authors independently extracted data and assessed the quality of included studies using the AMSTAR-2 (A MeaSurement Tool to Assess Systematic Reviews) checklist, and evidence assessment was performed using the GRADE (Grading of recommendations, Assessment, Development and Evaluation). Random-effects models were applied to calculate relative risk (RR) or odds ratios (OR) with 95% confidence intervals (CI). This study was registered with PROSPERO (CRD42022332052).

Results

With trial evidence from 11 systematic reviews and meta-analyses, we found that the use of glucagon-like peptide-1 receptor agonists (GLP-1 RA), sodium-glucose cotransporter-2 inhibitors (SGLT-2i), or dipeptidyl peptidase-4 inhibitors (DPP-4i) was not statistically associated with the risk of DR, compared to either placebo (RR: GLP-1 RA, 0.98, 0.89-1.08; SGLT-2i, 1.00, 95% CI 0.79-1.27; DPP-4i, 1.17, 0.99-1.39) or other antidiabetic drugs. Compared to other antidiabetic drugs, meglitinides (0.34, 0.01-8.25), SGLT-2i (0.73, 0.10-5.16), thiazolidinediones (0.92, 0.67-1.26), metformin (1.15, 0.81-1.63), sulphonylureas (1.24, 0.93-1.65), and acarbose (4.21, 0.44-40.43) were not statistically associated with the risk of DR. With evidence from longitudinal studies only, insulin was found to have a higher risk of DR than other antidiabetic drugs (OR: 2.47, 95% CI: 2.04-2.99).

Conclusion

Our results indicate that antidiabetic drugs are generally safe to prescribe regarding the risk of DR among people with type 2 diabetes. Further robust and large-scale trials investigating the effects of insulin, meglitinides, and acarbose on DR are warranted.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=332052, identifier CRD42022332052.

Challenging Clinical Perspectives in Type 2 Diabetes with Tirzepatide, a First-in-Class Twincretin

Tirzepatide is a first-in-class GIP/GLP-1 receptor agonist ('twincretin')-a single molecule that acts as an agonist at both glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors. In the SURPASS clinical trial program in type 2 diabetes mellitus (T2D), tirzepatide was associated with unprecedented reductions in HbA1c, clinically significant weight loss and other metabolic benefits, combined with low rates of hypoglycaemia across a wide range of patient characteristics. The safety and adverse event rate for tirzepatide appears comparable to that of GLP-1 receptor agonists. Although results from dedicated cardiovascular (CV) and kidney trials are currently not available, information to date suggests that tirzepatide may have CV and kidney benefits in people with T2D. Tirzepatide has been approved for the treatment of T2D in the USA, United Arab Emirates, European Union, Japan and Australia. Here, we review how tirzepatide will fit into the T2D treatment continuum. We also consider future directions with tirzepatide in T2D, including its potential for targeting cardio-renal-metabolic disease in T2D, and discuss how tirzepatide-and other co-agonists in development-may challenge current approaches for management of T2D.

GLP-1 receptor agonists and diabetic retinopathy: A meta-analysis of randomized clinical trials

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are used to treat type 2 diabetes mellitus. Recent research suggests that GLP-1 RAs may influence diabetic retinopathy (DR). We searched ClinicalTrials.gov for trials comparing FDA-approved GLP-1 RAs to placebo, insulin, or oral antidiabetic medicine. Rates of DR, ocular adverse events, demographics, and clinical characteristics were compared amongst cohorts on 93 trials. GLP-1 RA use was significantly associated with increased risk of early-stage DR (risk ratio (RR) = 1.31, 95% confidence interval (CI) [1.01, 1.68]) and early-stage retinal adverse events (RR = 1.29, 95% CI [1.01, 1.66]) compared to placebo. Compared to insulin, GLP-1 RA use protected against late-stage DR (RR = 0.38, 95% CI [0.15, 0.98]). Analysis of individual GLP-1 RAs showed that albiglutide is responsible for these trends, as it is significantly associated with a higher risk of early-stage DR (RR = 2.18, 95% CI [1.01, 4.67]) compared to placebo and a lower risk of late-stage DR (RR = 0.25, 95% CI [0.09, 0.70]) compared to insulin. Albiglutide similarly affected retinal and ocular adverse events. Demographic analysis revealed significant differences between GLP-1 RA and comparator groups for age, HbA1c, body weight, BMI, duration of diabetes, sex, race, and ethnicity. The influence of GLP-1 RAs on DR and the eye may depend on the specific GLP-1 RA and patient demographic and clinical characteristics.

Treatment‐induced neuropathy of diabetes: an update

Background and aims: Treatment‐induced neuropathy of diabetes is an acute small‐fibre neuropathy associated with rapid glycaemia improvement.

Methods: This study is a narrative review carried out based on a bibliographic review, using articles indexed in PubMed/Medline and Scielo.

Results: This entity is more frequent in adult patients with poor previous glycaemic control. Its precise pathophysiology is unknown, but it is likely related to unrestored microcirculation changes that occurred during the hyperglycaemic period. It presents with intense, sudden neuropathic pain and autonomic dysfunction after a rapid glycaemic correction and a poorer analgesic response than in diabetic neuropathy.

Conclusions: Since rapid glycaemia correction is the cause of this problem, clinical practice guidelines that can help physicians to prevent, diagnose and manage this entity should be developed. Copyright © 2023 John Wiley & Sons.

Mechanisms of Diabetic Nephropathy Not Mediated by Hyperglycemia

Diabetes mellitus (DM) is characterized by the appearance of progressive kidney damage, which may progress to end-stage kidney disease. The control of hyperglycemia is usually not sufficient to halt this progression. The kidney damage is quantitatively and qualitatively different in the two forms of diabetes; the typical nodular fibrosis (Kimmelstiel Wilson nodules) appears mostly in type 1 DM, whereas glomerulomegaly is primarily present in type 2 obese DM. An analysis of the different metabolites and hormones in type 1 and type 2 DM and their differential pharmacological treatments might be helpful to advance the hypotheses on the different histopathological patterns of the kidneys and their responses to sodium/glucose transporter type 2 inhibitors (SGLT2i).

Retinal Microvascular Density and Perfusion during an Insulin-Induced Hypoglycemia Episode: A Warning Call

Aim

To evaluate retinal vascular perfusion and density by optical coherence tomography angiography (OCTA) before, during, and after hypoglycemia in individuals with diabetes mellitus with or without diabetic retinopathy (DR).

Methods

A focused clinical history was performed, followed by an ophthalmological examination to document retinopathy status. OCTA was performed at baseline, at hypoglycemia, and at glucose normalization. Eye tracking and eye alignment devices on the platform were used to obtain a macular thickness cube (512 × 128) and vascular perfusion and density protocols of 3 × 3 mm. Retinal vascular reactivity was analyzed with superficial plexus vascular perfusion and density protocols on OCTA.

Results

Fifty-two participants encompassing 97 eyes fulfilled the eligibility criteria. Their mean age was 42.9 ± 15.1 years (range, 22 to 65), and 20 (38.2%) were men. We found a statistically significant difference in vascular perfusion and density when comparing all groups at baseline. The controls had higher vascular perfusion and density values than the cases. Vascular perfusion and density were significantly reduced in all groups during the hypoglycemia episode, except for vascular density in DR cases.

Conclusion

Acute hypoglycemia significantly alters the retinal vascularity in DM patients with and without DR, suggesting that repeated episodes of acute hypoglycemia could exacerbate retinopathy in the long term.

Effects of amygdalin on ferroptosis and oxidative stress in diabetic retinopathy progression via the NRF2/ARE signaling pathway

Oxidative stress has been involved in the pathogenesis of diabetic retinopathy (DR). Amygdalin is an effective component of bitter almond that exhibits excellent antioxidant properties. We explored the effects of amygdalin on ferroptosis and oxidative stress in high-glucose (HG)-stimulated human retinal endothelial cells (HRECs) via the NRF2/ARE pathway. HG-stimulated HRECs were used to establish a DR model. Cell viability was evaluated using the MTT assay. The release of lactate dehydrogenase was used to evaluate cell toxicity. The protein levels of NRF2, NQO1, and HO-1 were detected using western blotting. The GSH, GSSG, GPX4, SOD, CAT, MDA, and Fe2+ levels in the HRECs were also detected. Flow cytometry was used to detect reactive oxygen species (ROS) using a fluorescent probe. Immunofluorescence staining was performed to detect NRF2 expression. The results revealed that HG stimulation decreased the levels of GSH, GPX4, SOD, and CAT but increased those of MDA, ROS, GSSG, and Fe2+ in HRECs. Ferrostatin-1 treatment reversed the effects of HG stimulation, whereas erastin aggravated these effects. Amygdalin treatment relieved HG-induced injury in HRECs. Amygdalin treatment promoted the nuclear transport of NRF2 in HG-stimulated HRECs. NQO1 and HO-1 levels were upregulated in HG-stimulated HRECs after amygdalin treatment. An inhibitor of NRF2 reversed the effects of amygdalin. Therefore, amygdalin treatment inhibited ferroptosis and oxidative stress in HG-stimulated HRECs by activating the NRF2/ARE signaling pathway.

Vitamin D deficiency and diabetic retinopathy risk

PURPOSE

Vitamin D deficiency may play an important role in the development and progression of diabetic retinopathy. The present study aimed to assess the relationship between vitamin D deficiency and the likelihood of diabetic retinopathy.

METHODS

This nested case-control study was conducted on all type II diabetic patients among the participants of the third phase of the Shahroud eye cohort study. Overall, 278 patients aged 50 to 74 years, 101 in the case group (diabetic retinopathy) and 178 in the control group (diabetic without retinopathy), were assessed. Serum levels of vitamin D on admission were measured for all participants by a radio immunoassay (RIA) technique.

RESULTS

The overall prevalence of vitamin D deficiency (defined as a vitamin D level of less than or equal to 20mg/dL) was 30.7%. Comparison of the serum level of vitamin D across the three groups - without retinopathy, with non-proliferative retinopathy, and with proliferative retinopathy - showed a significantly lower level of this marker in the latter group (P=0.036). Reducing vitamin D to less than or equal to 20ng/mL increased the odds of proliferative retinopathy by 6.25 times (P value: 0.027).

CONCLUSION

Vitamin D deficiency is a potential risk factor for diabetes-related proliferative retinopathy.

What else can we do to prevent diabetic retinopathy?

The classical modifiable factors associated with the onset and progression of diabetic retinopathy are the suboptimal control of blood glucose levels and hypertension, as well as dyslipidaemia. However, there are other less recognised modifiable factors that can play a relevant role, such as the presence of obesity or the abnormal distribution of adipose tissue, and others related to lifestyle such as the type of diet, vitamin intake, exercise, smoking and sunlight exposure. In this article we revisit the prevention of diabetic retinopathy based on modulating the modifiable risk factors, as well as commenting on the potential impact of glucose-lowering drugs on the condition. The emerging concept that neurodegeneration is an early event in the development of diabetic retinopathy points to neuroprotection as a potential therapeutic strategy to prevent the advanced stages of the disease. In this regard, the better phenotyping of very early stages of diabetic retinopathy and the opportunity of arresting its progression using treatments targeting the neurovascular unit (NVU) are discussed.