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

How early can we detect diabetic retinopathy? A narrative review of imaging tools for structural assessment of the retina

Despite current screening models, enhanced imaging modalities, and treatment regimens, diabetic retinopathy (DR) remains one of the leading causes of vision loss in working age adults. DR can result in irreversible structural and functional retinal damage, leading to visual impairment and reduced quality of life. Given potentially irreversible photoreceptor damage, diagnosis and treatment at the earliest stages will provide the best opportunity to avoid visual disturbances or retinopathy progression. We will review herein the current structural imaging methods used for DR assessment and their capability of detecting DR in the first stages of disease. Imaging tools, such as fundus photography, optical coherence tomography, fundus fluorescein angiography, optical coherence tomography angiography and adaptive optics-assisted imaging will be reviewed. Finally, we describe the future of DR screening programmes and the introduction of artificial intelligence as an innovative approach to detecting subtle changes in the diabetic retina. CLINICAL TRIAL REGISTRATION NUMBER: N/A.

Screening for diabetic retinopathy at a health centre in South Africa: A cross-sectional study

Background

In South Africa, screening for diabetic retinopathy (DR) is non-existent at the primary healthcare (PHC) level because of the absence of a screening programme. This leads to preventable vision loss.

Aim

To describe the clinical characteristics and outcomes of eye screenings and subsequent referrals.

Setting

Laudium Community Health Centre (CHC), a PHC facility in Tshwane.

Methods

We conducted a cross-sectional study from February 2022 to August 2022. Individuals with diabetes were screened for eye complications using visual acuity testing, intraocular pressure measurement, and fundoscopy with a non-mydriatic digital fundus camera. Fundus images were analysed by an optometrist and an artificial intelligence (AI) programme. Demographic and clinical data were collected.

Results

A total of 120 participants were included, with the majority (60.7%) from Laudium CHC. Most participants (64.2%) were on oral agents, and 66.7% were women. The mean haemoglobin A1c (HbA1c) was 8.3%, with a median diabetes duration of 8 years. Artificial intelligence detected more glaucoma cases (17.5% vs 9.2%) and DR (23.3% vs 15.8%) compared to the optometrist. In contrast, the optometrist identified more cases of macula pathology (29.2% vs 19.2%). Participants (n = 79) were referred to an ophthalmologist for diagnosis confirmation and management.

Conclusion

The study revealed that while DR was not highly prevalent among PHC patients with diabetes, there was a significant referral rate for other ocular complications. Artificial intelligence can enhance early detection and improve efficiency.

Contribution

The findings underscore the need to integrate diabetes eye screening programmes into PHC services for people living with diabetes.

Factors associated with the uptake and utilisation of diabetic retinopathy screening services in sub-Saharan Africa: A scoping review

INTRODUCTION

Diabetic Retinopathy (DR) is a microvascular complication of chronic Diabetes that can lead to visual impairment if left untreated. While concerted efforts have been made to develop screening modalities to facilitate the early detection of Diabetic Retinopathy in sub-Saharan Africa, little is known about the factors impacting the optimal use of these screening services. This paper aims to identify and highlight factors associated with the access of Diabetic Retinopathy screening services from patient and service provider perspectives.

METHODOLOGY

This scoping review was conducted using the Arksey and O'Malley (2005) framework. A comprehensive search of peer-reviewed articles and grey literature was conducted from May 2023 to June 2023. Electronic databases searched include Medline, Embase, PubMed, CINAHL Complete, APA PsycINFO, Web of Science, and African Journal Online (AJOL). Two reviewers independently screened the retrieved records for eligibility, and relevant data was extracted from the included studies. A descriptive overview of key findings was provided, and the 5As conceptual framework of access to healthcare was used to map the identified factors.

RESULTS

The search strategy yielded 873 records. Of those, 19 studies met the criteria for inclusion. Health literacy and duration of Diabetes were reported in 12 and 9 studies as the most common factors associated with DR screening services access. Similarly, age at onset and inadequate referral by healthcare providers were cited as significant determinants of DR screening access in 7 studies, respectively.

CONCLUSION

The 5As framework of access to healthcare aids our understanding of factors associated with the access of DR screening from patient and service provider standpoints. To address these issues, there is a need for more research on this topic to design effective DR screening services in the region.

Sheffield One-Stop Service: A potential model to improve the screening uptake of diabetic peripheral neuropathy and other microvascular complications of diabetes

The world is experiencing an enormous rise in the prevalence of diabetes, which is associated with massive healthcare costs that threaten to overwhelm many healthcare systems. Most of the diabetes expenditure is attributed to the management of chronic diabetes complications, including diabetic peripheral neuropathy (DPN)/diabetic foot complications, chronic kidney disease, sight-threatening retinopathy and cardiovascular diseases. Of these complications, the most overlooked is DPN. Most consultations around the world do not even involve taking off shoes and socks to carry out a foot examination, and even when carried out, the peripheral neurological examination using the 10-g monofilament diagnoses DPN when it is already at an advanced stage. Thus, all too often diabetes complications are diagnosed late, resulting in devastating outcomes, particularly in low- to middle-income countries. There is, therefore, an urgent need to instigate new strategies to improve microvascular screening uptake using a holistic protocol for annual diabetes health checks outside the busy diabetes clinic. One such approach, the Sheffield One-Stop Microvascular Screening Service, which involves modern point of care devices to diagnose DPN, has been shown to be feasible and effective, resulting in high uptake and early management of diabetes complications. This article outlines the advantages of this One-Stop Microvascular Screening Service and a plan to trial an adapted version of this service to a resource-limited country, the Philippines. If successful, this model has the potential for implementation in other countries around the world.

Prevalence of vision impairment, diabetic retinopathy and disability in adults 50+ in the occupied Palestinian territories

The Rapid Assessment of Avoidable Blindness methodology is a population-based survey of vision impairment among the population 50 and above, with optional modules on diabetes, diabetic retinopathy and disability. The first Rapid Assessment of Avoidable Blindness study in the occupied Palestinian territories (oPt) was conducted in 2008. Prevalence of blindness (50+) was 3.4%. 80% of blindness was avoidable. Between July 2018 and April 2019, we completed a nationally-representative follow up survey in oPt using the Rapid Assessment of Avoidable Blindness methodology including the optional modules. We tested distance visual acuity (presenting and pinhole) using a bespoke mobile data collection application. 4223 Palestinians aged 50 years and above were enumerated, of whom 3847 participated (response rate 91.1%). Prevalence of any vision impairment (presenting vision impairment <6/12 in the better seeing eye), blindness (<3/60), severe vision impairment (<6/60 but ≥3/60), moderate vision impairment (<6/18 but ≥6/60) and mild vision impairment (<6/12 but ≥6/18) were 25.8% (95% confidence interval [CI] 23.8-27.8%), 2.6% (1.9-3.2%), 1.4% (1.0-1.8%), 10.2% (9.1-11.2%) and 11.6% (10.3-12.8%), respectively. Avoidable causes of poor vision accounted for 82.4% of blindness, 83.3% of severe vision impairment, 82.0% of moderate vision impairment and 90.2% of mild vision impairment. Diabetes prevalence (reported or suspected based on random blood glucose ≥200 milligrams/decilitre) was 33.8% (32.1-35.5). Half of diabetes participants had diabetic retinopathy and/or maculopathy. Prevalence of disability (reported functional limitations) was 23.8% (21.0-26.5), and higher in women than men. The prevalence of vision impairment and blindness in oPt compared with 2008 was similar. Prevalence of diabetes, diabetic retinopathy and disability were all high, highlighting key areas for public health prioritization among older adults in oPt.

Health transition and eye care policy planning for people with diabetic retinopathy in south Asia

The prevalence of type 2 diabetes (T2D), associated systemic disorders, diabetic retinopathy (DR) and current health policies in south Asian countries were analysed to assess country-specific preparedness to meet the 2030 Sustainable Development Goals. The south Asian countries were classified by human development index, socio-demographic index, multidimensional poverty indices, and eye health resources for epidemiological resource-level analysis. In south Asia, the prevalence of diagnosed and undiagnosed T2D in adults aged 40 years or above, was higher in Pakistan (26.3%) and Afghanistan (71.4%), respectively; India has the highest absolute number of people with DR, and Afghanistan has the highest prevalence of DR (50.6%). In this region, out-of-pocket spending is high (∼77%). This Health Policy is a situational analysis of data available on the prevalence of DR and common eye diseases in people with T2D in south Asia and available resources to suggest tailored health policies to local needs. The common issues in the region are insufficient human resources for eye health, unequal distribution of available workforce, and inadequate infrastructure. Addressing these challenges of individuals with T2D and DR, a 10-point strategy is suggested to improve infrastructure, augment human resources, reduce out-of-pocket spending, employ targeted screening, and encourage public-private partnerships.

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.

The Value of White Cell Inflammatory Biomarkers as Potential Predictors for Diabetic Retinopathy in Type 2 Diabetes Mellitus (T2DM)

The pathogenesis of diabetic retinopathy is still challenging, with recent evidence proving the key role of inflammation in the damage of the retinal neurovascular unit. This study aims to investigate the predictive value of the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte (PLR), lymphocyte-to-monocyte ratio (LMR), and systemic inflammation index (SII) for diabetic retinopathy (DR) and its severity. We performed a retrospective study on 129 T2DM patients, divided into three groups: without retinopathy (NDR), non-proliferative DR (NPDR), and proliferative DR (PDR). NLR, MLR, and SII were significantly higher in the PDR group when compared to NDR and NPDR (3.2 ± 1.6 vs. 2.4 ± 0.9 and 2.4 ± 1.1; p = 0.005; 0.376 ± 0.216 vs. 0.269 ± 0.083 and 0.275 ± 0.111, p = 0.001; 754.4 ± 514.4 vs. 551.5 ± 215.1 and 560.3 ± 248.6, p = 0.013, respectively). PDR was correlated with serum creatinine (OR: 2.551), NLR (OR: 1.645), MPV (OR: 1.41), and duration of diabetes (OR: 1.301). Logistic regression analysis identified three predictive models with very good discrimination power for PDR (AUC ROC of 0.803, 0.809, and 0.830, respectively): combining duration of diabetes with NLR, MLR, and, respectively, PLR, MPV, and serum creatinine. NLR, MPV, SII, and LMR were associated with PDR and could be useful when integrated into comprehensive risk prediction models.