The Effect of Bariatric Surgery on Diabetic Retinopathy: Good, Bad, or Both?

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.

Impact of Bariatric Surgery on Treatment Burden and Progression of Diabetic Retinopathy

Purpose: To assess the severity, progression, and treatment burden of diabetic retinopathy (DR) in patients after bariatric surgery compared with controls. Methods: A retrospective cohort study was performed of patients with type 2 diabetes and DR seen at the Duke Eye Center between 2014 and 2023. Clinical data included hemoglobin A1c (HbA1c), diagnostic stage of DR, diabetic macular edema (DME) or vitreous hemorrhage (VH), visual acuity (VA), and treatment burden at baseline and follow-up. Generalized estimating equation analysis was used to account for the correlation between 2 eyes of the same patient. Results: Sixteen patients who had bariatric surgery were matched by age, sex, and duration of diabetes with 60 control patients managed medically during the same time period. The HbA1c level, severity of DR, presence of DME or VH, VA, and treatment burden were not significantly different (all P > .05) at the baseline examination. On average, patients were followed for 6 years. The HbA1c level at the follow-up was significantly lower in the bariatric surgery group (6.4% vs 8.5%; P < .001). At the follow-up, the treatment burden was reduced in the bariatric surgery group compared with the control group (P = .04). There was a clear trend toward reduced progression of DR and treatment burden in the bariatric surgery group over the follow-up. Conclusions: Bariatric surgery may improve glycemic control, stabilize DR progression, and reduce the treatment burden, which may have a significant impact on quality of life for patients with DR.

Rapid Reduction of HbA1c and Early Worsening of Diabetic Retinopathy: A Real-world Population-Based Study in Subjects With Type 2 Diabetes

OBJECTIVE

Early worsening of diabetic retinopathy (EWDR) due to the rapid decrease of blood glucose levels is a concern in diabetes treatment. The aim of the current study is to evaluate whether this is an important issue in subjects with type 2 diabetes with mild or moderate nonproliferative DR (NPDR), who represent the vast majority of subjects with DR attended in primary care.

RESEARCH DESIGN AND METHODS

This is a retrospective nested case-control study of subjects with type 2 diabetes and previous mild or moderate NPDR. Using the SIDIAP ("Sistema d'informació pel Desenvolupament de la Recerca a Atenció Primària") database, we selected 1,150 individuals with EWDR and 1,150 matched control subjects (DR without EWDR). The main variable analyzed was the magnitude of the reduction of HbA1c in the previous 12 months. The reduction of HbA1c was categorized as rapid (>1.5% reduction in <12 months) or very rapid (>2% in <6 months).

RESULTS

We did not find any significant difference in HbA1c reduction between case and control subjects (0.13 ± 1.21 vs. 0.21 ± 1.18; P = 0.12). HbA1c reduction did not show significant association with worsening of DR, neither in the unadjusted analyses nor in adjusted statistical models that included the main confounding variables: duration of diabetes, baseline HbA1c, presence of hypertension, and antidiabetic drugs. In addition, when stratification by baseline HbA1c was performed, we did not find that those patients with higher levels of HbA1c presented a higher risk to EWDR.

CONCLUSIONS

Our results suggest that the rapid reduction of HbA1c is not associated with progression of mild or moderate NPDR.

New Insights into Treating Early and Advanced Stage Diabetic Retinopathy

Diabetic retinopathy (DR) is the leading cause of preventable blindness in the working-age population. The disease progresses slowly, and we can roughly differentiate two stages: early-stage (ESDR), in which there are mild retinal lesions and visual acuity is generally preserved, and advanced-stage (ASDR), in which the structural lesions are significant and visual acuity is compromised. At present, there are no specific treatments for ESDR and the current recommended action is to optimize metabolic control and maintain close control of blood pressure. However, in the coming years, it is foreseeable that therapeutic strategies based in neuroprotection will be introduced in the clinical arena. This means that screening aimed at identifying patients in whom neuroprotective treatment might be beneficial will be crucial. Regarding the treatment of ASDR, the current primary course is based on laser photocoagulation and intravitreal injections of anti-angiogenic factors or corticosteroids. Repeated intravitreal injections of anti-VEGF agents as the first-line treatment would be replaced by more cost-effective and personalized treatments based on the results of “liquid biopsies” of aqueous humor. Finally, topical administration (i.e., eye drops) of neuroprotective, anti-inflammatory and anti-angiogenic agents will represent a revolution in the treatment of DR in the coming decade. In this article, all these approaches and others will be critically discussed from a holistic perspective.

Early microvascular complications in type 1 and type 2 diabetes: recent developments and updates

The prevalence of youth-onset diabetes is progressing rapidly worldwide, and poor glycemic control, in combination with prolonged diabetes duration and comorbidities including hypertension, has led to the early development of microvascular complications including diabetic kidney disease, retinopathy, and neuropathy. Pediatric populations with type 1 (T1D) and type 2 (T2D) diabetes are classically underdiagnosed with microvascular complications, and this leads to both undertreatment and insufficient attention to the mitigation of risk factors that could help attenuate further progression of complications and decrease the likelihood for long-term morbidity and mortality. This narrative review aims to present a comprehensive summary of the epidemiology, risk factors, symptoms, screening practices, and treatment options, including future opportunities for treatment advancement, for microvascular complications in youth with T1D and T2D. We seek to uniquely focus on the inherent challenges of managing pediatric populations with diabetes and discuss the similarities and differences between microvascular complications in T1D and T2D, while presenting a strong emphasis on the importance of early identification of at-risk youth. Further investigation of possible treatment mechanisms for microvascular complications in youth with T1D and T2D through dedicated pediatric outcome trials is necessary to target the brief window where early pathological vascular changes may be significantly attenuated.

Future perspectives in diabesity treatment: Semaglutide, a glucagon-like peptide 1 receptor agonist (Review)

Given their endemic prevalence in the past decades, obesity and type 2 diabetes mellitus (T2DM) have become a major sanitary burden with an important economic impact. Novel treatment options have been designed with the aim of reducing the numerous complications associated with these metabolic disorders, as well as reducing morbidity and mortality and improving the quality of life of those who suffer from these disorders. Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) are among the most modern therapeutics that target ‘diabesity’, a term used to describe the pathophysiological link between obesity and T2DM. Their glucose-lowering effects are mainly attributed to glucose-dependent insulin secretion, glucagon inhibition and decreased gastric emptying. Given the effects on the central nervous system, GLP-1 RA usage may lead to body weight reduction. GLP-1 RAs are classified based on their pharmacokinetic properties as short- and long-acting agents, with both types being administered by subcutaneous injection. The latest agent from this drug class approved for use in T2DM is semaglutide, a long-acting compound that is the only GLP-1 RA available as an oral pill. The present narrative review highlights the most recently published data on the effects and safety of semaglutide in diabetic obesity, also emphasizing its cardiovascular benefits and potential side effects. In addition, an overview of the role of semaglutide in the treatment of non-diabetic obesity is provided.

Outcomes of Diabetic Retinopathy Post-Bariatric Surgery in Patients with Type 2 Diabetes Mellitus

Bariatric surgery is an emerging therapeutic approach for obese type 2 diabetes mellitus (T2DM) patients, with proven benefits for achieving target glucose control and even remission of diabetes. However, the effect of bariatric surgery upon diabetic retinopathy is still a subject of debate as some studies show a positive effect while others raise concerns about potential early worsening effects. We performed a systematic review, on PubMed, Science Direct, and Web of Science databases regarding the onset and progression of diabetic retinopathy in obese T2DM patients who underwent weight-loss surgical procedures. A total of 6375 T2DM patients were analyzed. Most cases remained stable after bariatric surgery (89.6%). New onset of diabetic retinopathy (DR) was documented in 290 out of 5972 patients (4.8%). In cases with DR at baseline, progression was documented in 50 out of 403 (12.4%) and regression in 90 (22.3%). Preoperative careful preparation of hemoglobin A1c (HbA1c), blood pressure, and lipidemia should be provided to minimize the expectation of DR worsening. Ophthalmologic follow-up should be continued regularly in the postoperative period even in the case of diabetic remission. Further randomized trials are needed to better understand the organ-specific risk factors for progression and provide personalized counseling for T2DM patients planned for bariatric surgery.

Safety of Semaglutide

The glucagon-like peptide-1 receptor agonist (GLP-1RA) semaglutide is the most recently approved agent of this drug class, and the only GLP-1RA currently available as both subcutaneous and oral formulation. While GLP-1RAs effectively improve glycemic control and cause weight loss, potential safety concerns have arisen over the years. For semaglutide, such concerns have been addressed in the extensive phase 3 registration trials including cardiovascular outcome trials for both subcutaneous (SUSTAIN: Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes) and oral (PIONEER: Peptide InnOvatioN for the Early diabEtes tReatment) semaglutide and are being studied in further trials and registries, including real world data studies. In the current review we discuss the occurrence of adverse events associated with semaglutide focusing on hypoglycemia, gastrointestinal side effects, pancreatic safety (pancreatitis and pancreatic cancer), thyroid cancer, gallbladder events, cardiovascular aspects, acute kidney injury, diabetic retinopathy (DRP) complications and injection-site and allergic reactions and where available, we highlight potential underlying mechanisms. Furthermore, we discuss whether effects are specific for semaglutide or a class effect. We conclude that semaglutide induces mostly mild-to-moderate and transient gastrointestinal disturbances and increases the risk of biliary disease (cholelithiasis). No unexpected safety issues have arisen to date, and the established safety profile for semaglutide is similar to that of other GLP-1RAs where definitive conclusions for pancreatic and thyroid cancer cannot be drawn at this point due to low incidence of these conditions. Due to its potent glucose-lowering effect, patients at risk for deterioration of existing DRP should be carefully monitored if treated with semaglutide, particularly if also treated with insulin. Given the beneficial metabolic and cardiovascular actions of semaglutide, and the low risk for severe adverse events, semaglutide has an overall favorable risk/benefit profile for patient with type 2 diabetes.

The Safety of Pharmacological and Surgical Treatment of Diabetes in Patients with Diabetic Retinopathy-A Review

BACKGROUND

Diabetes mellitus (DM) is a non-infectious pandemic of the modern world; it is estimated that in 2045 it will affect 10% of the world's population. As the prevalence of diabetes increases, the problem of its complications, including diabetic retinopathy (DR), grows. DR is a highly specific neurovascular complication of diabetes that occurs in more than one third of DM patients and accounts for 80% of complete vision loss cases in the diabetic population. We are currently witnessing many groundbreaking studies on new pharmacological and surgical methods of treating diabetes.

AIM

The aim of the study is to assess the safety of pharmacological and surgical treatment of DM in patients with DR.

MATERIAL AND METHODS

An analysis of the data on diabetes treatment methods currently available in the world literature and their impact on the occurrence and progression of DR.

RESULTS

A rapid decrease in glycaemia leads to an increased occurrence and progression of DR. Its greatest risk accompanies insulin therapy and sulfonylurea therapy. The lowest risk of DR occurs with the use of SGLT2 inhibitors; the use of DPP-4 inhibitors and GLP-1 analogues is also safe. Patients undergoing pancreatic islet transplants or bariatric surgeries require intensive monitoring of the state of the eye, both in the perioperative and postoperative period.

CONCLUSIONS

It is of utmost importance to individualize therapy in diabetic patients, in order to gradually achieve treatment goals with the use of safe methods and minimize the risk of development and progression of DR.

Clinical potential of treatment with semaglutide in type 2 diabetes patients

Glucagon-like receptor agonists (GLP-1RAs) are included in current national and international guidelines as second-line treatment especially in patients with type 2 diabetes and concomitant cardiovascular disease (CVD). First-generation GLP-1RAs were two- or once-daily injectables, but longer-acting GLP-1RAs have now been developed for once-weekly administration – e.g., exenatide ER, dulaglutide and semaglutide. With semaglutide, the same prolongation principle as designed in liraglutide is used (spacer and fatty acid chain). However, the similarity to endogenous human GLP-1 is well preserved, sharing 94% homology. It is administered with a simple device and without resuspension before use. The efficacy and safety of semaglutide have been investigated in an extensive clinical development program including more than 9,000 patients with type 2 diabetes. Semaglutide has been compared head-to-head with a dipeptidyl peptidase-4 (DPP4)-inhibitor, GLP-1RAs and basal insulin. Further head-to-head studies are awaiting that compare semaglutide against a sodium-dependent-glucose transporter-2 (SGLT2)-inhibitor. In these studies, semaglutide was found to provide significant and clinically relevant reductions in HbA1c, fasting plasma glucose (FPG), glucose excursions, body weight and blood pressure. The reduction in glycaemic parameters was more pronounced than that in the comparator GLP-1RAs. The rate of hypoglycemia is very low during treatment with semaglutide if not combined with sulphonylureas or insulin. A cardiovascular outcome trial (CVOT) was performed before the approval of semaglutide, at the request of legal authorities. Not only non-inferiority was confirmed, but also superiority compared with placebo used in a population of patients with type 2 diabetes and CVD treated with oral antihyperglycaemic drugs (OADs) and/or insulin with regard to the primary composite endpoint: death from cardiovascular (CV) causes, nonfatal myocardial infarction or nonfatal stroke. The safety of treatment with semaglutide in patients with type 2 diabetes has been extensively investigated. Overall, gastrointestinal side effects dominate, as observed with other GLP-1RAs, and was observed in the same range as for comparator GLP-1RAs. As observed with other GLP-1RAs, side effects such as nausea and vomiting diminished over time during continuous treatment. Regarding microvascular complications, an unexpected increase in diabetes-related retinopathy was observed in the CVOT; Semaglutide Unabated Sustainability in Treatment of Type 2 diabetes’ [SUSTAIN 6]), but not in other studies. The reason for this increase is not finally elucidated, but may be due to a nonspecific effect of a rapid decrease in glycaemic parameters in patients with preexisting retinopathy with high HbA1c at the start of the treatment. There is currently a warning in the Summary of Product Characteristics (SmPC) for semaglutide concerning treatment in patients with preexisting retinopathy. Further studies are needed to clarify this.

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

Worsening of diabetic retinopathy (DR) is associated with the initiation of effective treatment of glycaemia in some patients with diabetes. It has been associated with risk factors such as poor blood-glucose control and hypertension, and it manifests prior to the long-term benefits of optimizing glycaemic control. The majority of evidence supports an association of large and rapid reductions in blood-glucose levels with early worsening of DR. Despite a general awareness of early worsening within the diabetes community, mechanisms to explain the phenomenon remain speculative. We provide an overview of early worsening of DR and its pathophysiology based on current data. We describe the phenomenon in various settings, including in patients receiving insulin- or non-insulin-based treatments, in those undergoing bariatric surgery, and in pregnant women. We discuss various mechanisms and theories that have been suggested to explain this paradoxical phenomenon, and we summarize the implications of these in clinical practice.

Glucagon-Like Peptide 1 Receptor Agonists and the Risk of Incident Diabetic Retinopathy

OBJECTIVE

Previous studies suggested that glucagon-like peptide 1 receptor agonists (GLP-1 RAs) may initially worsen and possibly increase the risk of diabetic retinopathy. However, data on this possible association remain limited. Thus, this population-based study aimed to determine whether use of GLP-1 RAs is associated with an increased risk of incident diabetic retinopathy.

RESEARCH DESIGN AND METHODS

Using the U.K. Clinical Practice Research Datalink (CPRD), we conducted a cohort study among 77,115 patients with type 2 diabetes initiating antidiabetic drugs between January 2007 and September 2015. Adjusted hazard ratios (HRs) and 95% CIs of incident diabetic retinopathy were estimated using time-dependent Cox proportional hazards models, comparing use of GLP-1 RAs with current use of two or more oral antidiabetic drugs. In an ancillary analysis, new users of GLP-1 RAs were compared with new users of insulin.

RESULTS

During 245,825 person-years of follow-up, 10,763 patients were newly diagnosed with diabetic retinopathy. Compared with current use of two or more oral antidiabetic drugs, use of GLP-1 RAs was not associated with an increased risk of incident diabetic retinopathy overall (HR 1.00, 95% CI 0.85-1.17). Compared with insulin, GLP-1 RAs were associated with a decreased risk of diabetic retinopathy (HR 0.67, 95% CI 0.51-0.90).

CONCLUSIONS

The associations with diabetic retinopathy varied according to the type of comparator. When compared with use of two or more oral antidiabetic drugs, use of GLP-1 RAs was not associated with an increased risk of incident diabetic retinopathy. The apparent lower risk of diabetic retinopathy associated with GLP-1 RAs compared with insulin may be due to residual confounding.

MANAGEMENT OF ENDOCRINE DISEASE: Which metabolic procedure? Comparing outcomes in sleeve gastrectomy and Roux-en Y gastric bypass

Obesity and its associated comorbidities have become one of the largest challenges for health care in the near future. Conservative therapy for obesity and related comorbidities has a very high failure rate and poor long-term results. Similarly, the conservative and medical management of the majority of metabolic diseases such as type 2 diabetes mellitus are only able to slow down disease progression but have no causal effect on the disease process. Obesity surgery has evolved as a highly effective therapy for severe obesity achieving long-lasting weight loss. Furthermore, several studies have demonstrated the beneficial effects of obesity surgery on reduction of overall mortality, reduction of cardiovascular events and superior control of obesity-related diseases such as type 2 diabetes mellitus, dyslipidemia and also the non-alcoholic steatohepatitis compared to medical therapy. Based on these findings, the term 'metabolic surgery' with the focus on treating metabolic diseases independent of body weight has been coined. Of great interest are recent studies that show that even existing complications of metabolic diseases such as diabetic nephropathy or the non-alcoholic steatohepatitis can be reversed by metabolic surgery. Although metabolic surgery has proven to be a safe and effective treatment for obesity, resolution of comorbidities and enhancing quality of life, it is still uncertain and unclear, which surgical procedure is the most effective to achieve these metabolic effects. The aim of this review is to compare the effects of the two currently most widely used metabolic operations, the Roux-en-Y gastric bypass and the sleeve gastrectomy in the treatment of obesity and its related comorbidities.

Excess visceral adiposity is associated with diabetic retinopathy in a multiethnic Asian cohort with longstanding type 2 diabetes

Purpose/Aim: Diabetic retinopathy (DR) is the most common diabetic microvascular complication, and it typically develops after 10 years of diabetes diagnosis. The primary aim of this study was to evaluate the association between adiposity and DR susceptibility among individuals with longstanding type 2 diabetes mellitus (T2D).

MATERIALS AND METHODS

In this cross-sectional study, DR was assessed by fundus photography in 953 T2D subjects. DR prevalence by categories of T2D duration was evaluated. In a sub-cohort analysis, subjects having T2D for ≥10 years were divided into DR (N = 241) and non-DR (N = 377) groups. Measures of adiposity including body mass index (BMI), waist circumference (WC), and visceral fat area (VFA) were analyzed. Urinary albumin:creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR) were measured.

RESULTS

DR prevalence markedly increased 10 years after T2D diagnosis (p < 0.001). Among subjects with T2D duration ≥10 years, BMI, WC, and VFA were elevated in DR compared with non-DR (all p < 0.05). Contrasting with BMI and WC, the association between VFA and DR sustained adjustment for demographics, metabolic factors, and insulin treatment (OR: 1.060, 95% CI: 1.004-1.119, p = 0.035). However, the association became insignificant after controlling for ACR and eGFR. Mediation analysis revealed that ACR and eGFR explained 47.3% of the relationship between VFA and DR.

CONCLUSIONS

The findings suggest that visceral adiposity is associated with DR in individuals with longstanding T2D. This relationship may be attributable to generalized vascular injury as reflected by coexisting renal burden. Therefore, effective management of visceral adiposity and ameliorating renal burden may ameliorate susceptibility to DR.

Semaglutide, reduction in glycated haemoglobin and the risk of diabetic retinopathy

AIMS

To evaluate diabetic retinopathy (DR) data from across the SUSTAIN clinical trial programme.

MATERIALS AND METHODS

The SUSTAIN clinical trial programme evaluated the efficacy and safety of semaglutide, a glucagon-like peptide-1 analogue, for the treatment of type 2 diabetes (T2D). In SUSTAIN 6, a 2-year, pre-approval cardiovascular outcomes trial, semaglutide was associated with a significant increase in the risk of DR complications (DRC) vs placebo. DR data from across the SUSTAIN trials were evaluated, and post hoc analyses of the SUSTAIN 6 data were conducted. These included subgroup analyses to identify at-risk patients and a mediation analysis with initial change in glycated haemoglobin (HbA1c; percentage-points at week 16) as a covariate, to examine the role of the magnitude of reduction in HbA1c as an intermediate factor affecting risk of DRC.

RESULTS

There was no imbalance in DR adverse events across the SUSTAIN 1 to 5 and Japanese trials. The majority of the effect with semaglutide vs placebo in SUSTAIN 6 may be attributed to the magnitude and rapidity of HbA1c reduction during the first 16 weeks of treatment in patients who had pre-existing DR and poor glycaemic control at baseline, and who were treated with insulin.

CONCLUSIONS

Early worsening of DR is a known phenomenon associated with the rapidity and magnitude of improvement in glycaemic control with insulin; the DRC findings in SUSTAIN 6 are consistent with this. Guidance regarding the early worsening of DR is recommended with insulin. Similar recommendations may be appropriate for semaglutide.

Early worsening of diabetic retinopathy after rapid improvement of blood glucose control in patients with diabetes

AIM

To review the frequency, importance of and risk factors for "early worsening of diabetic retinopathy" (EWDR) after rapid improvement of blood glucose in patients with diabetes.

METHODS

This was a systematic review of key references (PubMed 1980-2016) and the current international recommendations for the above-mentioned topics.

RESULTS

EWDR has been described during intensive treatment (IT) in patients with uncontrolled type 1 or 2 diabetes, and after pancreas transplantation or bariatric surgery. EWDR arises in 10-20% of patients within 3-6 months after abrupt improvement of glucose control, and in nearly two times that proportion in patients with advanced baseline diabetic retinopathy (DR). While EWDR is often transient and predominantly driven by the development of cotton-wool spots and intraretinal microvascular abnormalities in patients with no or minimal DR, it can lead to irreversible retinal damage in patients with advanced DR before IT. Its identified risk factors include higher baseline levels and larger magnitudes of reduction of HbA_1c, longer diabetes durations and previous severity of DR.

CONCLUSION

Intensive diabetes treatment inducing a rapid fall in glucose should prompt vigilance and caution, particularly in patients with long-term and uncontrolled diabetes and DR prior to IT. Careful retinal examination should be performed in all patients before initiating IT; however, in patients with severe non-proliferative or proliferative DR, panretinal photocoagulation therapy should be performed promptly. During the year following IT, quarterly eye monitoring is required in patients at high risk of EWDR (long-term uncontrolled diabetes, previous advanced DR), whereas follow-up every 6 months can be applied in patients with short-term diabetes and no/minimal DR before IT. To date, there is no evidence that controlling the speed or magnitude of HbA_1c decreases will reduce the risk of EWDR in patients with diabetes.

The role of bariatric surgery to treat diabetes: current challenges and perspectives

Bariatric surgery is emerging as a powerful weapon against severe obesity and type 2 diabetes mellitus (T2DM). Given its role in metabolic regulation, the gastrointestinal tract constitutes a meaningful target to treat T2DM, especially in light of accumulating evidence that surgery with gastrointestinal manipulations may result in T2DM remission (metabolic surgery). The major mechanisms mediating the weight loss-independent effects of bariatric surgery comprise effects on tissue-specific insulin sensitivity, β-cell function and incretin responses, changes in bile acid composition and flow, modifications of gut microbiota, intestinal glucose metabolism and increased brown adipose tissue metabolic activity. Shorter T2DM duration, better preoperative glycemic control and profound weight loss, have been associated with higher rates of T2DM remission and lower risk of relapse. In the short and medium term, a significant amount of weight is lost, T2DM may completely regress, and cardiometabolic risk factors are dramatically improved. In the long term, metabolic surgery may achieve durable weight loss, prevent T2DM and cancer, improve overall glycemic control while leading to significant rates of T2DM remission, and reduce total and cause-specific mortality. The gradient of efficacy for weight loss and T2DM remission comparing the four established surgical procedures is biliopancreatic diversion >Roux-en-Y gastric bypass >sleeve gastrectomy >laparoscopic adjustable gastric banding. According to recently released guidelines, bariatric surgery should be recommended in diabetic patients with class III obesity, regardless of their level of glycemic control, and patients with class II obesity with inadequately controlled T2DM despite lifestyle and optimal medical therapy. Surgery should also be considered in patients with class I obesity and inadequately controlled hyperglycemia despite optimal medical treatment.

Bariatric Surgery for Adolescents with Type 2 Diabetes: an Emerging Therapeutic Strategy

PURPOSE OF REVIEW

Type 2 diabetes (T2D) is a growing public health problem in youth, but conventional treatments are often insufficient to treat this disease and its comorbidities. We review evidence supporting an emerging role for bariatric surgery as a treatment for adolescent T2D.

RECENT FINDINGS

Paralleling what has been seen in adult patients, bariatric surgery dramatically improves glycemic control in patients with T2D. In fact, remission of T2D has been observed in as many as 95-100% of adolescents with diabetes after bariatric surgery, particularly vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) surgery. This striking outcome may be due to both weight-dependent- and weight-independent factors, and recent studies suggest that T2D-related comorbidities may also improve after surgery. Bariatric surgery including RYGB and VSG is a powerful therapeutic option for obese adolescents with T2D. Benefits must be weighed against risk for postoperative complications such as nutritional deficiencies, but earlier surgical intervention might lead to more complete metabolic remission in obese patients with T2D.

GLP-1R as a Target for the Treatment of Diabetic Retinopathy: Friend or Foe?

Glucagon-like peptide 1 receptor (GLP-1R) agonists are increasingly being used as treatment for type 2 diabetes. Since the U.S. Food and Drug Administration published recommendations about the cardiovascular safety of new antidiabetes therapies for treating type 2 diabetes in 2008, the results of two outstanding clinical trials using GLP-1R agonists addressing this issue (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results-A Long Term Evaluation [LEADER] and Trial to Evaluate Cardiovascular and Other Long-term Outcomes With Semaglutide in Subjects With Type 2 Diabetes [SUSTAIN-6]) have been published. Both studies found beneficial effects in terms of reducing the rates of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. However, their results regarding the progression of diabetic retinopathy (DR) were neutral with liraglutide (LEADER) or worse when compared with placebo in the case of semaglutide (SUSTAIN-6). These results are surprising because of the beneficial effects of GLP-1R analogs reported in experimental models of DR. In this Perspective, an overview of the mechanisms by which GLP-1R activation exerts its effects in preventing or arresting experimental DR is given. In addition, we consider the possible reasons for the negative results regarding the progression of DR in the SUSTAIN-6 study, as well as the gaps that still need to be covered to further clarify this important issue in the management of type 2 diabetes.