Implementation of a diabetic retinopathy referral network, Peru

Present and future screening programs for diabetic retinopathy: a narrative review

Diabetes is a prevalent global concern, with an estimated 12% of the global adult population affected by 2045. Diabetic retinopathy (DR), a sight-threatening complication, has spurred diverse screening approaches worldwide due to advances in DR knowledge, rapid technological developments in retinal imaging and variations in healthcare resources.Many high income countries have fully implemented or are on the verge of completing a national Diabetic Eye Screening Programme (DESP). Although there have been some improvements in DR screening in Africa, Asia, and American countries further progress is needed. In low-income countries, only one out of 29, partially implemented a DESP, while 21 out of 50 lower-middle-income countries have started the DR policy cycle. Among upper-middle-income countries, a third of 59 nations have advanced in DR agenda-setting, with five having a comprehensive national DESP and 11 in the early stages of implementation.Many nations use 2-4 fields fundus images, proven effective with 80-98% sensitivity and 86-100% specificity compared to the traditional seven-field evaluation for DR. A cell phone based screening with a hand held retinal camera presents a potential low-cost alternative as imaging device. While this method in low-resource settings may not entirely match the sensitivity and specificity of seven-field stereoscopic photography, positive outcomes are observed.Individualized DR screening intervals are the standard in many high-resource nations. In countries that lacks a national DESP and resources, screening are more sporadic, i.e. screening intervals are not evidence-based and often less frequently, which can lead to late recognition of treatment required DR.The rising global prevalence of DR poses an economic challenge to nationwide screening programs AI-algorithms have showed high sensitivity and specificity for detection of DR and could provide a promising solution for the future screening burden.In summary, this narrative review enlightens on the epidemiology of DR and the necessity for effective DR screening programs. Worldwide evolution in existing approaches for DR screening has showed promising results but has also revealed limitations. Technological advancements, such as handheld imaging devices, tele ophthalmology and artificial intelligence enhance cost-effectiveness, but also the accessibility of DR screening in countries with low resources or where distance to or a shortage of ophthalmologists exists.

Rodent Models of Diabetic Retinopathy as a Useful Research Tool to Study Neurovascular Cross-Talk

Diabetes is a group of metabolic diseases leading to dysfunction of various organs, including ocular complications such as diabetic retinopathy (DR). Nowadays, DR treatments involve invasive options and are applied at the sight-threatening stages of DR. It is important to investigate noninvasive or pharmacological methods enabling the disease to be controlled at the early stage or to prevent ocular complications. Animal models are useful in DR laboratory practice, and this review is dedicated to them. The first part describes the characteristics of the most commonly used genetic rodent models in DR research. The second part focuses on the main chemically induced models. The authors pay particular attention to the streptozotocin model. Moreover, this section is enriched with practical aspects and contains the current protocols used in research in the last three years. Both parts include suggestions on which aspect of DR can be tested using a given model and the disadvantages of each model. Although animal models show huge variability, they are still an important and irreplaceable research tool. Note that the choice of a research model should be thoroughly considered and dependent on the aspect of the disease to be analyzed.

Inclusion of diabetic retinopathy screening strategies in national-level diabetes care planning in low- and middle-income countries: a scoping review

BACKGROUND

Diabetes is a major public health concern, with approximately 80% of the burden falling on low- and middle-income countries (LMICs). Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes, and early detection through diabetic eye screening programmes is essential to prevent visual impairment and blindness. Careful planning at a national level is crucial for effective implementation of such programmes.

METHODS

A scoping review was conducted, and the protocol was published previously to explain the methods in detail. Data were collected from databases and searches, including grey literature. Furthermore, consultations were conducted with key informants from LMICs.

RESULTS

Lower-middle-income countries (29/50, 58%) and upper-middle-income countries (27/59, 45.8%) are making more progress than low-income countries (4/29, 13.8%) in terms of DR policy planning. However, no identified data for published policies have actually implemented national DR policies. Compared to low-income and lower-middle-income countries, upper-middle-income countries are making the most progress in implementing national diabetic eye screening programmes; however, their progress is still slow, with only 5/59 (8.5%) having such programmes.

CONCLUSION

There are significant gaps in the literature, with no data reported for 78/138 (56.5%) LMICs. Further research is clearly needed to support and document DR policy development in LMICs.

Intravitreal aflibercept for the treatment of patients with diabetic macular edema in routine clinical practice in Latin America: the AQUILA study

BACKGROUND

AQUILA (NCT03470103) was a prospective, observational, 12-month cohort study to understand treatment patterns and to evaluate the clinical effectiveness and safety of intravitreal aflibercept (IVT-AFL) in patients from Latin America with diabetic macular edema (DME).

METHODS

Treatment-naïve and previously treated (switching to IVT-AFL) patients (aged ≥ 18 years) were enrolled from March 2018, with a primary completion date of September 2020, from Argentina, Colombia, Costa Rica and Mexico. Patients received IVT-AFL in a routine clinical practice setting.

RESULTS

Of 258 patients in the full analysis set, 181 were treatment-naïve and 77 had received previous treatment. The mean ± standard deviation number of IVT-AFL injections by Month 12 was 3.7 ± 1.8 (treatment-naïve) and 4.0 ± 2.2 (previously treated). The median duration from diagnosis to IVT-AFL treatment was 1.8 months (treatment-naïve) and 16.0 months (previously treated). Mean best-corrected visual acuity (Early Treatment Diabetic Retinopathy Study letters) improved from baseline to Month 12 by + 8.1 ± 17.7 (treatment-naïve; baseline: 54.5 ± 19.4) and + 4.6 ± 15.4 letters (previously treated; baseline: 52.9 ± 18.6).

CONCLUSION

AQUILA is the first study to assess the use of IVT-AFL in routine clinical practice in Latin America. Despite few patients being treated with the label-recommended regimen of 5 initial monthly doses or receiving ≥ 8 injections in 12 months, functional and anatomic visual outcomes improved during 12 months of treatment with IVT-AFL. Patients receiving the label-recommended number of injections had numerically greater improvements in visual acuity outcomes. Patients with DME treated regularly and more frequently with IVT-AFL therefore have the potential to achieve outcomes consistent with those observed in interventional studies. Trial registration Clinicaltrials.gov, NCT03470103. Registered February 5, 2018, https://clinicaltrials.gov/ct2/show/NCT03470103.

Implementation research on noncommunicable disease prevention and control interventions in low- and middle-income countries: A systematic review

BACKGROUND

While the evidence for the clinical effectiveness of most noncommunicable disease (NCD) prevention and treatment interventions is well established, care delivery models and means of scaling these up in a variety of resource-constrained health systems are not. The objective of this review was to synthesize evidence on the current state of implementation research on priority NCD prevention and control interventions provided by health systems in low- and middle-income countries (LMICs).

METHODS AND FINDINGS

On January 20, 2021, we searched MEDLINE and EMBASE databases from 1990 through 2020 to identify implementation research studies that focused on the World Health Organization (WHO) priority NCD prevention and control interventions targeting cardiovascular disease, cancer, diabetes, and chronic respiratory disease and provided within health systems in LMICs. Any empirical and peer-reviewed studies that focused on these interventions and reported implementation outcomes were eligible for inclusion. Given the focus on this review and the heterogeneity in aims and methodologies of included studies, risk of bias assessment to understand how effect size may have been compromised by bias is not applicable. We instead commented on the distribution of research designs and discussed about stronger/weaker designs. We synthesized extracted data using descriptive statistics and following the review protocol registered in PROSPERO (CRD42021252969). Of 9,683 potential studies and 7,419 unique records screened for inclusion, 222 eligible studies evaluated 265 priority NCD prevention and control interventions implemented in 62 countries (6% in low-income countries and 90% in middle-income countries). The number of studies published has been increasing over time. Nearly 40% of all the studies were on cervical cancer. With regards to intervention type, screening accounted for 49%, treatment for 39%, while prevention for 12% (with 80% of the latter focusing on prevention of the NCD behavior risk factors). Feasibility (38%) was the most studied implementation outcome followed by adoption (23%); few studies addressed sustainability. The implementation strategies were not specified well enough. Most studies used quantitative methods (86%). The weakest study design, preexperimental, and the strongest study design, experimental, were respectively employed in 25% and 24% of included studies. Approximately 72% of studies reported funding, with international funding being the predominant source. The majority of studies were proof of concept or pilot (88%) and targeted the micro level of health system (79%). Less than 5% of studies report using implementation research framework.

CONCLUSIONS

Despite growth in implementation research on NCDs in LMICs, we found major gaps in the science. Future studies should prioritize implementation at scale, target higher levels health systems (meso and macro levels), and test sustainability of NCD programs. They should employ designs with stronger internal validity, be more conceptually driven, and use mixed methods to understand mechanisms. To maximize impact of the research under limited resources, adding implementation science outcomes to effectiveness research and regional collaborations are promising.

Barriers in establishing systematic diabetic retinopathy screening through telemedicine in low- and middle-income countries

Vision-threatening diabetic retinopathy (VTDR) is one of the leading causes of impaired vision in the working-age population. Early identification, timely diagnosis, and prompt treatment of VTDR have to be tackled simultaneously to reduce the rate of blindness due to this condition. Considerable emphasis has been placed globally on establishing diabetic retinopathy screening (DRS) programs to enable early identification and referral of VTDR for treatment. However, there is an urgent need to shift from the common practice of opportunistic screening to a systematic DRS pathway to ensure that individuals with diabetes are screened at regular intervals and treated appropriately. While systematic DRS programs have been successfully established in countries such as the United Kingdom (UK), it continues to be a challenge to initiate and sustain such programs in low- and middle-income countries (LMIC), home to approximately 80% of people with diabetes. Telemedicine is widely recognized as an ideal DRS screening program. Although it has resulted in an upsurge of opportunistic screening, systematic recall of screened patients remains a challenge. In addition, the link between referred patients from the telemedicine programs to treatment centers is often not established or has failed to deliver; so, there is minimal impact of these telemedicine programs on VTDR blindness at present. This review covers the various barriers of establishing and sustaining systematic telemedicine DRS programs, especially in resource-constrained settings, and the challenges in aligning telemedicine to VTDR treatment pathways to ensure patients with VTDR are treated promptly and effectively.

Screening Diabetic Retinopathy Using an Automated Retinal Image Analysis System in Independent and Assistive Use Cases in Mexico: Randomized Controlled Trial

BACKGROUND

The automated screening of patients at risk of developing diabetic retinopathy represents an opportunity to improve their midterm outcome and lower the public expenditure associated with direct and indirect costs of common sight-threatening complications of diabetes.

OBJECTIVE

This study aimed to develop and evaluate the performance of an automated deep learning-based system to classify retinal fundus images as referable and nonreferable diabetic retinopathy cases, from international and Mexican patients. In particular, we aimed to evaluate the performance of the automated retina image analysis (ARIA) system under an independent scheme (ie, only ARIA screening) and 2 assistive schemes (ie, hybrid ARIA plus ophthalmologist screening), using a web-based platform for remote image analysis to determine and compare the sensibility and specificity of the 3 schemes.

METHODS

A randomized controlled experiment was performed where 17 ophthalmologists were asked to classify a series of retinal fundus images under 3 different conditions. The conditions were to (1) screen the fundus image by themselves (solo); (2) screen the fundus image after exposure to the retina image classification of the ARIA system (ARIA answer); and (3) screen the fundus image after exposure to the classification of the ARIA system, as well as its level of confidence and an attention map highlighting the most important areas of interest in the image according to the ARIA system (ARIA explanation). The ophthalmologists' classification in each condition and the result from the ARIA system were compared against a gold standard generated by consulting and aggregating the opinion of 3 retina specialists for each fundus image.

RESULTS

The ARIA system was able to classify referable vs nonreferable cases with an area under the receiver operating characteristic curve of 98%, a sensitivity of 95.1%, and a specificity of 91.5% for international patient cases. There was an area under the receiver operating characteristic curve of 98.3%, a sensitivity of 95.2%, and a specificity of 90% for Mexican patient cases. The ARIA system performance was more successful than the average performance of the 17 ophthalmologists enrolled in the study. Additionally, the results suggest that the ARIA system can be useful as an assistive tool, as sensitivity was significantly higher in the experimental condition where ophthalmologists were exposed to the ARIA system's answer prior to their own classification (93.3%), compared with the sensitivity of the condition where participants assessed the images independently (87.3%; P=.05).

CONCLUSIONS

These results demonstrate that both independent and assistive use cases of the ARIA system present, for Latin American countries such as Mexico, a substantial opportunity toward expanding the monitoring capacity for the early detection of diabetes-related blindness.

The P2X7 Receptor: A Promising Pharmacological Target in Diabetic Retinopathy

Diabetes is a worldwide emergency. Its chronic complications impose a heavy burden on patients, health systems, and on society as a whole. Diabetic retinopathy is one of the most common and serious complications of diabetes, and an established risk factor for blindness in adults. Over 15 years of investigation led to the identification of vascular endothelial growth factor (VEGF) as a main pathogenic factor in diabetic retinopathy and to the introduction of highly effective anti-VEGF-based therapies, such as the monoclonal antibody bevacizumab or its fragment ranibizumab, which helped to prevent diabetes-related blindness in millions of patients. Recently, a pathogenic role for uncontrolled increases in the extracellular ATP concentration (eATP) and for overactivation of the purinergic receptor P2X7 (P2X7R) has been suggested. The P2X7R is an eATP-gated plasma membrane channel expressed in multiple tissues and organs, with a pleiotropic function in inflammation, immunity, cancer, and hormone and growth factor release. P2X7R stimulation or overexpression positively regulate the secretion and buildup of VEGF, thus promoting neo-angiogenesis in a wide variety of disease processes. In this review, we explore current evidence that supports the role of P2X7R receptor signaling in the pathogenesis of diabetic retinopathy, as well as the most appealing current therapeutical options for P2X7R targeting.

Utilization of eye health services and diabetic retinopathy: a cross-sectional study among persons living with diabetes visiting a tertiary eye care facility in Ghana

BACKGROUND

There have been a major advance made in screening, early diagnosis, and prompt treatment of Diabetic Retinopathy among Person living with diabetes (PLWD). However, screening services remain a challenge in Low-Middle-Income-Countries where access to eye care professionals is inadequate. This study assesses the utilization of Eye Health Service prevalence (UEHS) among PLWD and associated factors and further quantifies its association with Non-Proliferative Diabetic Retinopathy (NPDR).

METHODS

A cross-sectional study design with a random sample of 360 PLWD was conducted at Korle-Bu Teaching Hospital, a National Referral Centre in Ghana from May to July 2019. UEHS and DR were the study outcomes. We adopted Poisson and Probit regression analysis to assess factors associated with UEHS over the past year. We employed pairwise and phi correlation (fourfold correlational analysis) to assess the relationship between UEHS and DR (ordinal and binary respectively). Ordered Logistic and Poisson regression were applied to assess the association between the UEHS and DR. Stata 16.1 was used to perform the analyses and a p-value ≤ 0.05 was deemed significant.

RESULTS

The prevalence of UEHS over the past year and DR was 21.7 %(95 %CI = 17.7-26.2) and 65.0 %(95 %CI = 59.9-69.8 respectively. The prevalence of severe NPDR with Clinically Significant Macular Edema (CSME) was 23.9 %(19.8-28.6). Type of diabetes, increasing age, educational level, mode of payment for healthcare services, marital status, years since diagnosis, and current blood glucose significantly influenced UEHS. There was a negative relationship between DR and UEHS (Pairwise and φ correlation were - 20 and - 15 respectively; p < 0.001). Non-UEHS among PLWD doubles the likelihood of experiencing severe NPDR with CSME compared with UEHS among PLWD [aOR(95 %CI) = 2.05(1.03-4.08)]. Meanwhile, the prevalence of DR among patients per non-UEHS was insignificantly higher [12 %; aPR(95 %CI) = 0.89-1.41)] compared with patients who utilized eye care health service.

CONCLUSIONS

Most of the PLWD did not utilize the eye health service even once in a year and that was highly influenced by type of diabetes and increasing age. Type 2 diabetes patients and middle age decreased the likelihood of UEHS. There was a negative relationship between DR and UEHS among PLWD and this doubled the likelihood of experiencing severe NPDR with CSME. Structured health education and screening interventions are key to improving UEHS.

Diabetes care quality according to facility setting: A cross-sectional analysis in six Peruvian regions

OBJECTIVE

To characterize diabetes care across healthcare facilities in six Peruvian regions.

METHODS

Cross-sectional study of patients with type 2 diabetes mellitus (T2DM), ranging from primary care facilities to hospital-based facilities, in six Peruvian regions. Data was collected by health staff trained between 2012 and 2016. We studied six diabetes care outcomes and four adequate diabetes care outcomes considering the healthcare facility as the exposure of interest. We estimated prevalence ratios (PR) and their 95% confidence intervals (95% CI) using Poisson regression with robust variance.

RESULTS

Data from 8879 patients with T2DM, mean age 59.1 years (SD ± 12.2), 53.6% males, was analyzed. Of these, 8096 (91.2%) were treated at primary care facilities. The proportions of patients who had HbA1c, LDL-c, and creatinine/microalbumin test performed increased with the setting of the healthcare facility. Overall, 39%-56% of patients had an adequate HbA1c control, being higher in hospital-based facilities with specialists in comparison to primary care facilities.

CONCLUSIONS

We observed that the higher the setting of the facility, the higher the rate of the assessed diabetes care outcomes and adequate diabetes care for four of the six targets (fasting glucose, HbA1c, LDL-c and creatinine or microalbumin) and for three of the four targets (glucose≤130 mg/dL, HbA1c ≤7%(53 mmol/mol) and LDL-c <100 mg/dL), respectively. Substantial gaps were observed at the primary care facilities, calling for the strengthening of diabetes care.

Current State of Diabetes Mellitus Prevalence, Awareness, Treatment, and Control in Latin America: Challenges and Innovative Solutions to Improve Health Outcomes Across the Continent

PURPOSE OF REVIEW

Latin America is the scenario of great inequalities where about 32 million human beings live with diabetes. Through this review, we aimed at describing the current state of the prevalence, awareness, treatment, and control of diabetes mellitus and completion of selected guidelines of care across Latin America and identify opportunities to advance research that promotes better health outcomes.

RECENT FINDINGS

The prevalence of diabetes mellitus has been consistently increasing across the region, with some variation: higher prevalence in Mexico, Haiti, and Puerto Rico and lower in Colombia, Ecuador, Dominican Republic, Peru, and Uruguay. Prevalence assessment methods vary, and potentially underestimating the real number of persons with diabetes. Diabetes unawareness varies widely, with up to 50% of persons with diabetes who do not know they may have the disease. Glycemic, blood pressure, and LDL-C control and completion of guidelines to prevent microvascular complications are not consistently assessed across studies, and the achievement of control goals is suboptimal. On the other hand, multiple interventions, point-of-care/rapid assessment tools, and alternative models of health care delivery have been proposed and tested throughout Latin America. The prevalence of diabetes mellitus continues to rise across Latin America, and the number of those with the disease may be underestimated. However, some local governments are embedding more comprehensive diabetes assessments in their local national surveys. Clinicians and public health advocates in the region have proposed and initiated various multi-level interventions to address this enormous challenge in the region.

The Role of Telemedicine to Alleviate an Increasingly Burdened Healthcare System: Retinopathy of Prematurity

Telemedicine-based remote digital fundus imaging (RDFI-TM) offers a promising platform for the screening of retinopathy of prematurity. RDFI-TM addresses some of the challenges faced by ophthalmologists in examining this vulnerable population in both low- and high-income countries. In this review, we studied the evidence on the use of RDFI-TM and analyzed the practical framework for RDFI-TM systems. We assessed the novel technological advances that can be deployed within RDFI-TM systems including noncontact imaging systems, smartphone-based imaging tools, and deep learning algorithms.

Association of transcription factor 7-like 2 (rs7903146) gene polymorphism with diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is one of the most common diabetic complications. Genetic factors play an important role in the development and progression of DR. So, the present study aimed to investigate the association of TCF7L2 (rs7903146) gene polymorphism with the risk of DR in type1 and type2 DM (T1DM and T2DM) in the Egyptian population.

MATERIALS AND METHODS

This work is a case-control study in which 550 diabetic patients were enrolled. Among them, 280 diabetics with DR (120 T1DM and 160 with T2DM) and 270 diabetic patients without DR (120 T1DM and 150 with T2DM). Besides, 120 healthy subjects as a control group. Genotyping of TCF7L2 (rs7903146) (C/T) was done following DNA extraction using polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

C allele and CC genotype of TCF7L2 (rs7903146) were significantly associated with increased risk for DR within T2DM in multiplicative and recessive models. While dominant model showed no significant association with DR. Although TC may be associated with a decreased risk for DR in T1DM and T2DM in over dominant model, there was no significant association of TCF7L2 (rs7903146) with the risk of DR susceptibility within T1DM in multiplicative, dominant, and recessive models.

CONCLUSION

The present study revealed the association of TCF7L2 (rs7903146) polymorphism with DR susceptibility within diabetic patients. Therefore, TCF7L2 (rs7903146) gene polymorphism may have a prognostic value for diabetic retinopathy in the Egyptian population. Further work is required to confirm the association of this polymorphism as a risk for DR.

Blood-retinal barrier protection against high glucose damage: The role of P2X7 receptor

Blood retinal barrier (BRB) breakdown is a hallmark of diabetic retinopathy, whose occurrence in early or later phases of the disease has not yet been completely clarified. Recent evidence suggests that hyperglycemia induces activation of the P2X7 receptor (P2X7R) leading to pericyte cell death. We herein investigated the role of P2X7R on retinal endothelial cells viability and expression of tight- and adherens-junctions following high glucose (HG) exposure. We found that HG elicited P2X7R activation and expression and release of the pro-inflammatory cytokine IL-1β in human retinal endothelial cells (HRECs). Furthermore, HG exposure caused a decrease in HRECs viability and a damage of the BRB. JNJ47965567, a P2X7R antagonist, protected HRECs from HG-induced damage (LDH release) and preserved the BRB, as shown by transendothelial electrical resistance and cell junction morphology (ZO-1, claudin-5 and VE-cadherin). Moreover, JNJ47965567 treatment significantly decreased IL-1β expression and release, elicited by HG. These data indicate that P2X7R plays an important role to regulate BRB integrity, in particular the block of this receptor was useful to counteract the damage elicited by HG in HRECs, and warranting further clinical evaluation of P2X7R antagonists for the treatment of diabetic macular edema.