Kidney and eye diseases: common risk factors, etiological mechanisms, and pathways. Kidney Int. 2014;85:1290-1302. [PMID: 24336029 DOI: 10.1038/ki.2013.491]

Is Kidney Function Associated with Age-Related Macular Degeneration?: Findings from the Asian Eye Epidemiology Consortium

PURPOSE

Chronic kidney disease (CKD) may elevate susceptibility to age-related macular degeneration (AMD) because of shared risk factors, pathogenic mechanisms, and genetic polymorphisms. Given the inconclusive findings in prior studies, we investigated this association using extensive datasets in the Asian Eye Epidemiology Consortium.

DESIGN

Cross-sectional study.

PARTICIPANTS

Fifty-one thousand two hundred fifty-three participants from 10 distinct population-based Asian studies.

METHODS

Age-related macular degeneration was defined using the Wisconsin Age-Related Maculopathy Grading System, the International Age-Related Maculopathy Epidemiological Study Group Classification, or the Beckman Clinical Classification. Chronic kidney disease was defined as estimated glomerular filtration rate (eGFR) of less than 60 ml/min per 1.73 m2. A pooled analysis using individual-level participant data was performed to examine the associations between CKD and eGFR with AMD (early and late), adjusting for age, sex, hypertension, diabetes, body mass index, smoking status, total cholesterol, and study groups.

MAIN OUTCOME MEASURES

Odds ratio (OR) of early and late AMD.

RESULTS

Among 51 253 participants (mean age, 54.1 ± 14.5 years), 5079 had CKD (9.9%). The prevalence of early AMD was 9.0%, and that of late AMD was 0.71%. After adjusting for confounders, individuals with CKD were associated with higher odds of late AMD (OR, 1.46; 95% confidence interval [CI], 1.11-1.93; P = 0.008). Similarly, poorer kidney function (per 10-unit eGFR decrease) was associated with late AMD (OR, 1.12; 95% CI, 1.05-1.19; P = 0.001). Nevertheless, CKD and eGFR were not associated significantly with early AMD (all P ≥ 0.149).

CONCLUSIONS

Pooled analysis from 10 distinct Asian population-based studies revealed that CKD and compromised kidney function are associated significantly with late AMD. This finding further underscores the importance of ocular examinations in patients with CKD.

FINANCIAL DISCLOSURE(S)

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

Evaluation of retinal microcirculation by optical coherence tomography angiography in patients with primary membranous nephropathy

BACKGROUND

Primary membranous nephropathy (PMN) patients may experience retinal microvascular changes. However, current diagnostic methods for PMN are not accurate in analyzing these modifications. In the present study, optical coherence tomography angiography (OCTA) was used for quantitative measurement of microvascular changes in the eyes of PMN patients.

METHODS

A total of 26 patients with PMN and 26 healthy control (HC) were evaluated in this cross-sectional study. Optical coherence tomography (OCT) and OCTA were used to collect retinal thickness (RT) and microvascular parameters in the macula and optic disk in the superficial capillary plexus (SCP) of all subjects. Clinical data were collected from the PMN group. The OCT and OCTA data for PMN and HC group were compared, and the correlation between the OCTA and clinical data in the PMN group was determined.

RESULTS

Vascular density (VD) and perfusion density (PD) in the macular area of the PMN group were significantly lower than those of the HC group, especially in the temporal quadrant. No significant difference in the foveal avascular zone (FAZ), optic disc microvascular parameters, RT, and retinal nerve fiber layer (RNFL) thickness was observed between the two groups. Correlation was noted between VD and PD in the macular area and clinical indicators, such as serum creatinine, serum urea nitrogen, 24-hour urine volume and urinary protein concentration.

CONCLUSION

Microvascular alterations in PMN patients occurred before ocular symptoms. The present quantitative study proposed a measurement method for detecting early retinal vascular injury in PMN patients.

Looking into the Eyes to See the Heart of Chronic Kidney Disease Patients

In patients with chronic kidney disease (CKD), the main cause of morbidity and mortality is cardiovascular disease (CVD). Both coronary artery calcium scoring by computed tomography (CT) and optical coherence tomography (OCT) are used to identify patients at increased risk for ischemic heart disease, thereby indicating a higher cardiovascular risk profile. Our study aimed to investigate the utility of these techniques in the CKD population. In patients with CKD, OCT was used to measure the choroidal thickness (CHT) and the thickness of the peripapillary retinal nerve fiber layer (pRNFL). A total of 127 patients were included, including 70 men (55%) with an estimated glomerular filtration rate (eGFR) of 39 ± 30 mL/min/1.73 m2. Lower pRNFL thickness was found to be related to high-sensitivity troponin I (r = -0.362, p < 0.001) and total coronary calcification (r = -0.194, p = 0.032). In a multivariate analysis, pRNFL measurements remained associated with age (β = -0.189; -0.739--0.027; p = 0.035) and high-sensitivity troponin I (β = -0.301; -0.259--0.071; p < 0.001). Severe coronary calcification (Agatston score ≥ 400 HU) was related to a worse eGFR (p = 0.008), a higher grade of CKD (p = 0.036), and a thinner pRNFL (p = 0.011). The ROC curve confirmed that the pRNFL measurement could determine the patients with an Agatston score of ≥400 HU (AUC 0.638; 95% CI 0.525-0.750; p = 0.015). Our study concludes that measurement of pRNFL thickness using OCT is related to the markers associated with ischemic heart disease, such as coronary calcification and high-sensitivity troponin I, in the CKD population.

Giant retinal pigment epithelium tears with membranous nephropathy: a case report and literature review

BACKGROUND

Kidney and eye diseases may be closely linked. Tears of the retinal pigment epithelium (RPE) have been reported to be related to kidney diseases, such as IgA nephropathy and light-chain deposition disease. However, pigment epithelium tears associated with membranous nephropathy have not been reported or systematically analysed.

CASE PRESENTATION

A 68-year-old man presented with decreased right eye visual acuity. Optical coherence tomography (OCT) revealed cystic macular edema, localized serous detachment of the retina and loss of the outer retinal structure in the right eye and retinal pigment epithelium detachment (PED) combined with serous detachment of the retina in the left eye. Fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) revealed giant RPE tears in the right eye and exudative age-related macular degeneration in the left eye. The patient also suffered from severe membranous nephropathy-autoimmune glomerulonephritis. Renal biopsy immunofluorescence revealed a roughly granular pattern, with immunoglobulin G (IgA), immunoglobulin G (IgG), IgM, complement C3(Components 3), λ light chain and κ light chain subepithelial staining.

CONCLUSIONS

It is hypothesized that severe membranous nephropathy caused immune complex deposition on the surface of Bruch membrane, resulting in weakened adhesion between the RPE and Bruch membrane and impaired RPE pump function, combined with age-related macular degeneration, leading to giant RPE tears in the right eye. Close attention should be given to the ocular condition of patients with membranous nephropathy to facilitate timely treatment and avoid serious consequences.

Optical coherence tomography angiography for the differentiation of diabetic nephropathy from non-diabetic renal disease

BACKGROUND

To provide a new non-invasive method for the differentiation of diabetic nephropathy (DN) from non-diabetic renal disease (NDRD) by assessing retinal microstructure using optical coherence tomography angiography (OCTA).

METHODS

OCTA parameters were recorded and their relationship with DN was analysed. A differential diagnosis regression model for DN was established, and the diagnostic efficiency was evaluated.

RESULTS

Based on the pathological results of renal biopsy, 31 DN patients and 35 NDRD patients were included. Multivariate logistic regression analysis showed that DN was independently associated with the following parameters: 15.3 mm-1 ≤ vessel density (VD) full < 17.369 mm-1 (odds ratio [OR]=8.523; 95% confidence interval [CI]=1.387-52.352; P = 0.021), VD full < 15.3 mm-1 (OR=8.202; 95% CI=1.110-60.623; P = 0.039), DM duration > 60 months (OR=7.588; 95% CI=1.569-36.692; P = 0.012), and estimated glomerular filtration rate < 60 mL/min/1.73 m2 (OR=24.484; 95% CI=4.308-139.142; P < 0.001). The area under the receiver operating characteristic curve was 0.911, indicating a high diagnostic efficiency.

CONCLUSIONS

VD full < 17.369 mm-1, DM duration > 60 months, and eGFR < 60 mL/min/1.73 m2 may indicate the presence of DN. OCTA may be an effective non-invasive method for identifying DN and NDRD.

Development and External Validation of Machine Learning Models for Diabetic Microvascular Complications: Cross-Sectional Study With Metabolites

BACKGROUND

Diabetic kidney disease (DKD) and diabetic retinopathy (DR) are major diabetic microvascular complications, contributing significantly to morbidity, disability, and mortality worldwide. The kidney and the eye, having similar microvascular structures and physiological and pathogenic features, may experience similar metabolic changes in diabetes.

OBJECTIVE

This study aimed to use machine learning (ML) methods integrated with metabolic data to identify biomarkers associated with DKD and DR in a multiethnic Asian population with diabetes, as well as to improve the performance of DKD and DR detection models beyond traditional risk factors.

METHODS

We used ML algorithms (logistic regression [LR] with Least Absolute Shrinkage and Selection Operator and gradient-boosting decision tree) to analyze 2772 adults with diabetes from the Singapore Epidemiology of Eye Diseases study, a population-based cross-sectional study conducted in Singapore (2004-2011). From 220 circulating metabolites and 19 risk factors, we selected the most important variables associated with DKD (defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2) and DR (defined as an Early Treatment Diabetic Retinopathy Study severity level ≥20). DKD and DR detection models were developed based on the variable selection results and externally validated on a sample of 5843 participants with diabetes from the UK biobank (2007-2010). Machine-learned model performance (area under the receiver operating characteristic curve [AUC] with 95% CI, sensitivity, and specificity) was compared to that of traditional LR adjusted for age, sex, diabetes duration, hemoglobin A1c, systolic blood pressure, and BMI.

RESULTS

Singapore Epidemiology of Eye Diseases participants had a median age of 61.7 (IQR 53.5-69.4) years, with 49.1% (1361/2772) being women, 20.2% (555/2753) having DKD, and 25.4% (685/2693) having DR. UK biobank participants had a median age of 61.0 (IQR 55.0-65.0) years, with 35.8% (2090/5843) being women, 6.7% (374/5570) having DKD, and 6.1% (355/5843) having DR. The ML algorithms identified diabetes duration, insulin usage, age, and tyrosine as the most important factors of both DKD and DR. DKD was additionally associated with cardiovascular disease history, antihypertensive medication use, and 3 metabolites (lactate, citrate, and cholesterol esters to total lipids ratio in intermediate-density lipoprotein), while DR was additionally associated with hemoglobin A1c, blood glucose, pulse pressure, and alanine. Machine-learned models for DKD and DR detection outperformed traditional LR models in both internal (AUC 0.838 vs 0.743 for DKD and 0.790 vs 0.764 for DR) and external validation (AUC 0.791 vs 0.691 for DKD and 0.778 vs 0.760 for DR).

CONCLUSIONS

This study highlighted diabetes duration, insulin usage, age, and circulating tyrosine as important factors in detecting DKD and DR. The integration of ML with biomedical big data enables biomarker discovery and improves disease detection beyond traditional risk factors.

Choroidal Vascularity Index and Choroidal Structural Changes in Children With Nephrotic Syndrome

Purpose

To investigate the choroidal vascularity index (CVI) and choroidal structural changes in children with nephrotic syndrome.

Methods

This was a cross-sectional study involving 45 children with primary nephrotic syndrome and 40 normal controls. All participants underwent enhanced depth imaging-optical coherence tomography examinations. An automatic segmentation method based on deep learning was used to segment the choroidal vessels and stroma, and the choroidal volume (CV), vascular volume (VV), and CVI within a 4.5 mm diameter circular area centered around the macular fovea were obtained. Clinical data, including blood lipids, serum proteins, renal function, and renal injury indicators, were collected from the patients.

Results

Compared with normal controls, children with nephrotic syndrome had a significant increase in CV (nephrotic syndrome: 4.132 ± 0.464 vs. normal controls: 3.873 ± 0.574; P = 0.024); no significant change in VV (nephrotic syndrome: 1.276 ± 0.173 vs. normal controls: 1.277 ± 0.165; P = 0.971); and a significant decrease in the CVI (nephrotic syndrome: 0.308 [range, 0.270-0.386] vs. normal controls: 0.330 [range, 0.288-0.387]; P < 0.001). In the correlation analysis, the CVI was positively correlated with serum total protein, serum albumin, serum prealbumin, ratio of serum albumin to globulin, and 24-hour urine volume and was negatively correlated with total cholesterol, low-density lipoprotein cholesterol, urinary protein concentration, and ratio of urinary transferrin to creatinine (all P < 0.05).

Conclusions

The CVI is significantly reduced in children with nephrotic syndrome, and the decrease in the CVI parallels the severity of kidney disease, indicating choroidal involvement in the process of nephrotic syndrome.

Translational Relevance

Our findings contribute to a deeper understanding of how nephrotic syndrome affects the choroid.

Susceptibility to eye diseases in relation to age and kidney failure among Taiwanese adults

BACKGROUND

The kidney and eyes share common pathways and are thought to be closely connected. Chronic kidney disease and major eye diseases, such as cataract and glaucoma, are strongly associated with age. However, further investigation is needed to understand the joint impact of age and kidney diseases on eye diseases. In this study, we assessed the risk of eye diseases in relation to age and kidney failure in Taiwanese adults.

METHODS

Our study included 127,561 cancer-free volunteers aged 30 to 70 years who participated in the Taiwan Biobank (TWB) project from 2008 to 2020. Information on the main exposures (kidney failure and age) and the outcome (eye diseases, including glaucoma, cataract, xerophthalmia, and retinal detachment) was collected through questionnaires.

RESULTS

In general, kidney failure and older age were independently associated with a higher risk of eye, particularly cataract and retinal detachment: prevalence odds ratio (POR); 95% confidence interval (CI) = 2.480; 1.635-3.761 for cataract and 3.885; 1.968-7.666 for retinal detachment. A significant interaction between kidney failure and age on cataract was observed (p-value = 0.0002). Age-stratified analysis revealed a higher risk of cataract among patients with kidney failure aged below 50 (POR = 6.534; 95% CI = 2.493-17.124) and between 50 and 60 years (POR = 3.957; 95%CI = 1.986-7.881). Combining kidney failure and age (reference: no kidney failure and age < 50 years), kidney failure in all age groups was associated with a higher risk of cataract. The PORs; 95% CIs were 10.725; 4.227-27.211 for patients below 50 years, 28.487; 14.270-56.866 for those aged 50-60 years, and 43.183; 24.434-72.824 for those > 60 years. Combining cataract and age (reference: no cataract and age < 50 years), patients below 50 years had the highest risk of kidney failure (POR; 95% CI = 9.510; 3.722-24.297).

CONCLUSIONS

Our study suggests that age and kidney failure may jointly contribute to eye diseases, particularly cataract. The association between cataract and kidney failure could be bidirectional, especially in individuals below 50 years. This significant bidirectional relationship underscores the need for screening patients with cataract for kidney failure and vice versa, particularly in younger adults.

Racial Disparities in Diabetes Care and Outcomes for Patients with Visual Impairment: A Descriptive Analysis of the TriNetX Research Network

Background: This research delves into the confluence of racial disparities and health inequities among individuals with disabilities, with a focus on those contending with both diabetes and visual impairment. Methods: Utilizing data from the TriNetX Research Network, which includes electronic medical records of roughly 115 million patients from 83 anonymous healthcare organizations, this study employs a directed acyclic graph (DAG) to pinpoint confounders and augment interpretation. We identified patients with visual impairments using ICD-10 codes, deliberately excluding diabetes-related ophthalmology complications. Our approach involved multiple race-stratified analyses, comparing co-morbidities like chronic pulmonary disease in visually impaired patients against their counterparts. We assessed healthcare access disparities by examining the frequency of annual visits, instances of two or more A1c measurements, and glomerular filtration rate (GFR) measurements. Additionally, we evaluated diabetes outcomes by comparing the risk ratio of uncontrolled diabetes (A1c > 9.0) and chronic kidney disease in patients with and without visual impairments. Results: The incidence of diabetes was substantially higher (nearly double) in individuals with visual impairments across White, Asian, and African American populations. Higher rates of chronic kidney disease were observed in visually impaired individuals, with a risk ratio of 1.79 for African American, 2.27 for White, and non-significant for the Asian group. A statistically significant difference in the risk ratio for uncontrolled diabetes was found only in the White cohort (0.843). White individuals without visual impairments were more likely to receive two A1c tests, a trend not significant in other racial groups. African Americans with visual impairments had a higher rate of glomerular filtration rate testing. However, White individuals with visual impairments were less likely to undergo GFR testing, indicating a disparity in kidney health monitoring. This pattern of disparity was not observed in the Asian cohort. Conclusions: This study uncovers pronounced disparities in diabetes incidence and management among individuals with visual impairments, particularly among White, Asian, and African American groups. Our DAG analysis illuminates the intricate interplay between SDoH, healthcare access, and frequency of crucial diabetes monitoring practices, highlighting visual impairment as both a medical and social issue.

Retinal neurovascular alteration in type 2 diabetes with renal impairment in association with systemic arterial stiffness

BACKGROUND

Diabetic retinopathy (DR) patients should be alert for subclinical macroangiopathy. We aimed to investigate the association between retinal neurovascular alteration and systemic arterial stiffness in type 2 diabetes mellitus (type 2 DM) patients with varying degrees of renal impairment.

METHODS

The study included 170 patients with confirmed diagnosis of type 2 DM aged ≥18 years old. Renal function was assessed by estimated glomerular filtration rate (eGFR). Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV) and ankle brachial index (ABI). Retinal neurovascular parameters were derived from Optical Coherence Tomography (OCT)/OCT-Angiography, represented by vessel density (VD Central, Inner, Outer, Full), foveal avascular zone (FAZ area and FAZ perimeter) of the superficial capillary plexus, the average of macular ganglion cell-inner plexiform layer thickness (ave mGC-IPLt) and the average of retinal nerve fiber layer thickness (aveRNFLt). The association between variables among the groups (according to renal function, diabetic retinopathy (DR) severity, and arterial stiffness categories) were analyzed by regression analysis with multiple hypothesis testing commands.

RESULTS

Out of the 265 eyes, the mean DM duration and HbA1c were 6.21 ± 6.37 years and 8.44 ± 2.06% respectively. While the mean of eGFR, baPWV and ABI were 66.78 ± 32.80 ml/min/1.73m2, 15.49 ± 3.07 m/s, and 1.05 ± 0.12, respectively. Patients with more severe renal impairment demonstrated longer DM duration (p < 0.001), higher baPWV (p < 0.0001), and retinal vascular alteration. Proliverative DR group showed the lowest eGFR (p < 0.0001), highest baPWV (p < 0.0001), and retinal neurovascular changes. Significantly lower eGFR and retinal vascular alteration were found in the baPWV > 14 group. Some neurovascular parameters were significantly negatively correlated with baPWV; moreover, retinal neurovascular changes were also noted in the abnormal ABI group.

CONCLUSIONS

The strong association between changes in the retinal neurovascular system, DR severity, renal impairment, and arterial stiffness in type 2 DM was confirmed. Patients with more severe renal impairment had higher levels of arterial stiffness, more severe DR and retinal neurovascular alteration. Retinal neurovascular changes seen in OCT/OCTA might mimic renal microvascular alteration and systemic arterial stiffness. Therefore, assessment of baPWV and OCT/OCTA should be integrated in DR screening to enhance cardiovascular risk stratification and prognosis as well as to provide clinically useful early identification of subclinical micro- and macrovascular alterations.

Associations between Chronic Kidney Disease and Thinning of Neuroretinal Layers in Multiethnic Asian and White Populations

Purpose

To evaluate the relationships between chronic kidney disease (CKD) with retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness profiles of eyes in Asian and White populations.

Design

Cross-sectional analysis.

Participants

A total of 5066 Asian participants (1367 Malays, 1772 Indians, and 1927 Chinese) from the Singapore Epidemiology of Eye Diseases Study (SEED) were included, consisting of 9594 eyes for peripapillary RNFL analysis and 8661 eyes for GCIPL analysis. Additionally, 45 064 White participants (87 649 eyes) from the United Kingdom Biobank (UKBB) were included for both macular RNFL analysis and GCIPL analysis.

Methods

Nonglaucoma participants aged ≥ 40 years with complete data for estimated glomerular filtration rate (eGFR) were included from both SEED and UKBB. In SEED, peripapillary RNFL and GCIPL thickness were measured by Cirrus HD-OCT 4000. In UKBB, macular RNFL and GCIPL were measured by Topcon 3D-OCT 1000 Mark II. Chronic kidney disease was defined as eGFR < 60 ml/min/1.73 m2 in both data sets. To evaluate the associations between kidney function status with RNFL and GCIPL thickness profiles, multivariable linear regression with generalized estimating equation models were performed in SEED and UKBB data sets separately.

Main Outcome Measures

Average peripapillary and macular RNFL thickness and macular GCIPL thickness.

Results

In SEED, after adjusting for age, gender, ethnicity, systolic blood pressure, antihypertensive medication, diabetes, hyperlipidemia, body mass index, smoking status, and intraocular pressure, presence of CKD (β = -1.31; 95% confidence interval [CI], -2.37 to -0.26; P = 0.015) and reduced eGFR (per 10 ml/min/1.73 m2; β = -0.32; 95% CI, -0.50 to -0.13; P = 0.001) were associated with thinner average peripapillary RNFL. Presence of CKD (β = -1.63; 95% CI, -2.42 to -0.84) and reduced eGFR (per 10 ml/min/1.73 m2; β = -0.30; 95% CI, -0.44 to -0.16) were consistently associated with thinner GCIPL in SEED (all P < 0.001). In UKBB, after adjusting for the above-mentioned covariates (except ethnicity), reduced eGFR (per 10 ml/min/1.73 m2; β = -0.06; 95% CI, -0.10 to -0.01; P = 0.008) was associated with thinner macular RNFL and CKD (β = -0.62; 95% CI, -1.16 to -0.08; P = 0.024) was associated with thinner average GCIPL.

Conclusion

We consistently observed associations between CKD and thinning of RNFL and GCIPL across Asian and White populations' eyes. These findings further suggest that compromised kidney function is associated with RNFL and GCIPL thinning.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A Review on Diabetic Retinopathy

Diabetic retinopathy is a well-recognised microvascular complication of diabetes and is among the leading cause of blindness all over the world. Over the last decade, there have been advances in the diagnosis of diabetic retinopathy and diabetic macular edema. At the same time, newer therapies for the management of diabetic retinopathy have evolved. As a result of these advances, a decline in severe vision loss due to diabetes has been witnessed in some developing countries. However, there is a steady increase in the number of people affected with diabetes, and is expected to rise further in the coming years. Therefore, it is prudent to identify diabetic retinopathy, and timely intervention is needed to decrease the burden of severe vision loss. An effort has been made to review all the existing knowledge regarding diabetic retinopathy in this article and summarize the present treatment options for diabetic retinopathy.

Choroidal and retinal thinning in chronic kidney disease independently associate with eGFR decline and are modifiable with treatment

In patients with chronic kidney disease (CKD), there is an unmet need for novel biomarkers that reliably track kidney injury, demonstrate treatment-response, and predict outcomes. Here, we investigate the potential of retinal optical coherence tomography (OCT) to achieve these ends in a series of prospective studies of patients with pre-dialysis CKD (including those with a kidney transplant), patients with kidney failure undergoing kidney transplantation, living kidney donors, and healthy volunteers. Compared to health, we observe similar retinal thinning and reduced macular volume in patients with CKD and in those with a kidney transplant. However, the choroidal thinning observed in CKD is not seen in patients with a kidney transplant whose choroids resemble those of healthy volunteers. In CKD, the degree of choroidal thinning relates to falling eGFR and extent of kidney scarring. Following kidney transplantation, choroidal thickness increases rapidly (~10%) and is maintained over 1-year, whereas gradual choroidal thinning is seen during the 12 months following kidney donation. In patients with CKD, retinal and choroidal thickness independently associate with eGFR decline over 2 years. These observations highlight the potential for retinal OCT to act as a non-invasive monitoring and prognostic biomarker of kidney injury.

Short-term duration of diabetic retinopathy as a predictor for development of diabetic kidney disease

Background

Diabetic retinopathy (DR) is a risk factor for diabetic kidney disease (DKD). Whether the duration, especially the short-term duration, of DR is associated with the development and progression of DKD remains unclear.

Materials and Methods

A retrospective study and two-sample Mendelian randomization (MR) analysis were conducted. Kidney disease was defined by the urinary albumin-to-creatinine ratio (ACR) and the estimated glomerular filtration rate (eGFR). DR was diagnosed by an expert ophthalmologist by using a digital fundus camera. Binary and ordinal logistic regression analyses were performed. A restricted cubic spline was utilized to detect nonlinear associations. Summary statistics for DR- and DKD-associated single-nuclear polymorphisms (SNPs) were extracted from the FinnGen and the UK Biobank consortia.

Results

A total of 2674 patients with type 2 diabetes mellitus (T2DM) and type 2 diabetic kidney disease (T2DKD) were included. The prevalence and mean duration of DR increased with elevation of ACR and decline in eGFR. Renal function was significantly reduced in patients with DR in the fifth year of life. Binary and ordinal logistic regression showed that each 1-year increase in DR duration was associated with a 19% risk increase in the development of DKD, 16% in the elevation of ACR, and 21% in the decline of renal function. MR estimates indicated that DR was causally associated with DKD development, with an odds ratio of 2.89.

Conclusions

DR and the duration of DR were independent risk factors for the development and progression of DKD. The short-term duration of DR may be associated with DKD development. DR had a statistically significant effect on DKD.

Choroidal structural changes in patients with early diabetic nephropathy

PURPOSE

To determine alterations of the choroidal thickness (CT) and the choroidal vascularity index (CVI) in patients with glomerular hyperfiltration, a marker of early diabetic nephropathy (DN).

METHODS

Twenty-two patients with type 2 diabetes (T2D) with glomerular hyperfiltration (early DN group) and 28 patients with T2D without DN (NDN group) were included in the study. Patients with diabetic retinopathy were excluded. Parameters including subfoveal CT, the subfoveal choroidal vascularity index (CVI), and total CVI were measured using spectral-domain enhanced depth imaging optical coherence tomography method.

RESULTS

The early DN group included 22 patients and the NDN group comprised 28 patients. The groups were similar in terms of age and sex (p>0.05). The CT values were statistically significantly lower in the early DN group than in the NDN group (p < 0.001). There was no significant difference between the early DN group and the NDN group in terms of total and subfoveal CVI (p>0.05).

CONCLUSION

The choroidal thickness decreased in patients with T2D with glomerular hyperfiltration, but there were no differences in CVI when they were compared with patients with T2D without DN.

Sodium-Glucose Cotransporter 2 Inhibitors and Risk of Retinopathy in Patients With Type 2 Diabetes

Importance

Diabetic nephropathy and diabetic retinopathy share many similarities in pathophysiological processes. Preclinical studies have shown that sodium-glucose cotransporter 2 inhibitors (SGLT2is) have a protective role in the risk of diabetic retinopathy.

Objective

To compare the risk of sight-threatening retinopathy associated with SGLT2is and other second-line glucose-lowering medications (including pioglitazone, sulfonylureas, and dipeptidyl peptidase-4 inhibitors [DPP-4is]) in patients with type 2 diabetes (T2D).

Design, Setting, and Participants

This cohort study in Taiwan applied a new-user and active-comparator design. Patient demographic and clinical data were obtained from the National Health Insurance Research Database. Adult patients with newly diagnosed T2D from January 1, 2009, to December 31, 2019, were recruited and followed up until December 31, 2020. Propensity score matching was used to identify pairs of patients treated with SGLT2i vs DPP-4i, SGLT2i vs pioglitazone, and SGLT2i vs sulfonylurea from January 1, 2016, to December 31, 2019. Data were analyzed between August 18, 2022, and May 5, 2023.

Exposures

Treatment with SGLT2i, DPP-4i, pioglitazone, and sulfonylureas starting on January 1, 2016.

Main Outcomes and Measures

The main outcome was sight-threatening retinopathy in participants. Cox proportional hazards regression models were used to assess relative hazards of sight-threatening retinopathy between the matched case and control groups.

Results

A total of 3 544 383 patients with newly diagnosed T2D were identified. After 1:1 propensity score matching, 65 930 pairs of patients treated with SGLT2i vs DPP-4i, 93 760 pairs treated with SGLT2i vs pioglitazone, and 42 121 pairs treated with SGLT2i vs sulfonylurea were identified. These matched patients included 236 574 males (58.6%), with a mean (SD) age of 56.9 (11.8) years. In the matched cohorts, SGLT2i had a significantly lower risk of sight-threatening retinopathy than DPP-4i (adjusted hazard ratio [AHR], 0.57; 95% CI, 0.51-0.63), pioglitazone (AHR, 0.75; 95% CI, 0.69-0.81), and sulfonylureas (AHR, 0.62; 95% CI, 0.53-0.71). The Kaplan-Meier curves showed that SGLT2i was associated with a significantly lower cumulative incidence of sight-threatening retinopathy than DPP-4i (3.52 vs 6.13; P < .001), pioglitazone (4.32 vs 5.76; P < .001), and sulfonylureas (2.94 vs 4.67; P < .001).

Conclusions and Relevance

This cohort study found that SGLT2i was associated with a lower risk of sight-threatening retinopathy compared with DPP-4i, pioglitazone, and sulfonylureas. This finding suggests that SGLT2i may play a role not only in reduced risk of diabetic nephropathy but also in the slow progression of diabetic retinopathy in patients with T2D.

Six-Year Incidence of Visual Impairment in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Purpose

To examine the 6-year incidence of visual impairment (VI) and identify risk factors associated with VI in a multiethnic Asian population.

Design

Prospective, population-based, cohort study.

Participants

Adults aged ≥ 40 years were recruited from the Singapore Epidemiology of Eye Diseases cohort study at baseline. Eligible subjects were re-examined after 6 years. Subjects included in the final analysis had a mean age of 56.1 ± 8.9 years, and 2801 (50.5%) were female.

Methods

All participants underwent standardized examination and interviewer-administered questionnaire at baseline. Incidences were standardized to the Singapore Population Census 2010. A Poisson binomial regression model was used to evaluate the associations between baseline factors and incident presenting VI.

Main Outcome Measures

Incident presenting VI was assessed at the 6-year follow-up visit. Visual impairment (presenting visual acuity < 20/40), low vision (presenting visual acuity < 20/40 but ≥ 20/200), and blindness (presenting visual acuity < 20/200) were defined based on United States definition.

Results

A total of 5551 subjects (2188 Chinese, 1837 Indians, and 1526 Malays) were evaluated, of whom 514 developed incident presenting VI over 6 years. Malays had a higher incidence of low vision and blindness (13.0%; 0.6%) than Indians (7.0%; 0.1%) and Chinese (7.7%; 0.2%). Among Malay individuals with VI at baseline, 52.8% remained visually impaired after 6 years, which was considerably higher than Chinese (32.4%) and Indians (37.2%). Older age (per decade; relative risk [RR] = 1.59), a history of cardiovascular disease (RR = 1.38), current smoking (RR = 1.31), smaller housing type (1- to 2-room public flat; RR = 2.01), and no formal education (RR = 1.63) at baseline were associated with a higher risk of incident VI (all P ≤ 0.027). Older age (> 60 years) contributed the highest population attributable risk to incident VI (27.1%), followed by lower monthly income (Singapore dollar < $2000; 26.4%) and smaller housing type (24.7%). Overall, undercorrected refractive error (49.1%) and cataract (82.6%) were leading causes for low vision and blindness, respectively. This was consistently observed across the 3 ethnicities.

Conclusions

In this multiethnic Asian population, Malays had a higher VI incidence compared to Indians and Chinese. Leading causes of VI are mostly treatable, suggesting that more efforts are needed to further mitigate preventable visual loss.

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

Examination of alternative eGFR definitions on the performance of deep learning models for detection of chronic kidney disease from fundus photographs

Deep learning (DL) models have shown promise in detecting chronic kidney disease (CKD) from fundus photographs. However, previous studies have utilized a serum creatinine-only estimated glomerular rate (eGFR) equation to measure kidney function despite the development of more up-to-date methods. In this study, we developed two sets of DL models using fundus images from the UK Biobank to ascertain the effects of using a creatinine and cystatin-C eGFR equation over the baseline creatinine-only eGFR equation on fundus image-based DL CKD predictors. Our results show that a creatinine and cystatin-C eGFR significantly improved classification performance over the baseline creatinine-only eGFR when the models were evaluated conventionally. However, these differences were no longer significant when the models were assessed on clinical labels based on ICD10. Furthermore, we also observed variations in model performance and systemic condition incidence between our study and the ones conducted previously. We hypothesize that limitations in existing eGFR equations and the paucity of retinal features uniquely indicative of CKD may contribute to these inconsistencies. These findings emphasize the need for developing more transparent models to facilitate a better understanding of the mechanisms underpinning the ability of DL models to detect CKD from fundus images.

Deep learning algorithms to detect diabetic kidney disease from retinal photographs in multiethnic populations with diabetes

OBJECTIVE

To develop a deep learning algorithm (DLA) to detect diabetic kideny disease (DKD) from retinal photographs of patients with diabetes, and evaluate performance in multiethnic populations.

MATERIALS AND METHODS

We trained 3 models: (1) image-only; (2) risk factor (RF)-only multivariable logistic regression (LR) model adjusted for age, sex, ethnicity, diabetes duration, HbA1c, systolic blood pressure; (3) hybrid multivariable LR model combining RF data and standardized z-scores from image-only model. Data from Singapore Integrated Diabetic Retinopathy Program (SiDRP) were used to develop (6066 participants with diabetes, primary-care-based) and internally validate (5-fold cross-validation) the models. External testing on 2 independent datasets: (1) Singapore Epidemiology of Eye Diseases (SEED) study (1885 participants with diabetes, population-based); (2) Singapore Macroangiopathy and Microvascular Reactivity in Type 2 Diabetes (SMART2D) (439 participants with diabetes, cross-sectional) in Singapore. Supplementary external testing on 2 Caucasian cohorts: (3) Australian Eye and Heart Study (AHES) (460 participants with diabetes, cross-sectional) and (4) Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) (265 participants with diabetes, cross-sectional).

RESULTS

In SiDRP validation, area under the curve (AUC) was 0.826(95% CI 0.818-0.833) for image-only, 0.847(0.840-0.854) for RF-only, and 0.866(0.859-0.872) for hybrid. Estimates with SEED were 0.764(0.743-0.785) for image-only, 0.802(0.783-0.822) for RF-only, and 0.828(0.810-0.846) for hybrid. In SMART2D, AUC was 0.726(0.686-0.765) for image-only, 0.701(0.660-0.741) in RF-only, 0.761(0.724-0.797) for hybrid.

DISCUSSION AND CONCLUSION

There is potential for DLA using retinal images as a screening adjunct for DKD among individuals with diabetes. This can value-add to existing DLA systems which diagnose diabetic retinopathy from retinal images, facilitating primary screening for DKD.

Retinal changes and cardiac biomarker assessment in relation to chronic kidney disease: a single centre study

BACKGROUND

The prevalence of chronic kidney disease (CKD) is rising in Malaysia. Early detection is necessary to prevent disease progression, especially in terms of cardiovascular (CV) risk, the main cause of death in end-stage renal disease (ESRD). Retinal changes have proven to be a good predictor of CKD whereas cardiac biomarkers are useful in cardiovascular risk stratification. We aimed to demonstrate the correlation between retinal changes and cardiac biomarkers with CKD.

METHODS

This single-centre cross-sectional study was conducted among patients with CKD stages 3, 4, and 5 (not on dialysis) from the Nephrology Clinic, Universiti Kebangsaan Malaysia Medical Centre. A total of 84 patients were recruited with an even distribution across all three stages. They underwent fundus photography where images were analysed for vessel calibre (central retinal venular equivalent (CRVE), central retinal arterial equivalent (CRAE), and tortuosity indices. Optical coherence tomography was used to measure macular volume. Blood samples were sent for laboratory measurement of high-sensitivity C-reactive protein (hs-CRP) and asymmetric dimethylarginine (ADMA). These parameters were analysed in relation to CKD.

RESULTS

The mean age was 58.8 ± 11.7 years, with 52.4% male and 47.6% female patients. Among them, 64.3% were diabetics. Retinal vessel tortuosity (r = -0.220, p-value = 0.044) had a negative correlation with the estimated glomerular filtration rate (eGFR). CRVE showed a positive correlation with proteinuria (r = 0.342, p = 0.001) but negative correlation with eGFR (r = -0.236, p = 0.031). Hs-CRP positively correlated with proteinuria (r = 0.313, p = 0.04) and negatively correlated with eGFR (r = -0.370, p = 0.001). Diabetic patients had a higher CRVE compared to non-diabetic patients (p = 0.02). History of ischaemic heart disease was associated with a smaller macula volume (p = 0.038). Male gender (r2 = 0.066, p = 0.031) and HbA1c had a positive influence (r2 = 0.066, p = 0.047) on retinal vessel tortuosity. There was a positive influence of age (r2 = 0.183, p = 0.012) and hs-CRP (r2 = 0.183, p = 0.045) on CRVE. As for macula volume, it negatively correlated with diabetes (r2 = 0.015, p = 0.040) and positively correlated with smoking (r2 = 0.015, p = 0.012).

CONCLUSION

Our study showed that eGFR value affects retinal vessel tortuosity, CRVE and hs-CRP. These parameters bear potential to be used as non-invasive tools in assessing CKD. However, only macula volume may be associated with CVD risk among the CKD population.

Evaluation of an Automated Choroid Segmentation Algorithm in a Longitudinal Kidney Donor and Recipient Cohort

Purpose

To evaluate the performance of an automated choroid segmentation algorithm in optical coherence tomography (OCT) data using a longitudinal kidney donor and recipient cohort.

Methods

We assessed 22 donors and 23 patients requiring renal transplantation over up to 1 year posttransplant. We measured choroidal thickness (CT) and area and compared our automated CT measurements to manual ones at the same locations. We estimated associations between choroidal measurements and markers of renal function (estimated glomerular filtration rate [eGFR], serum creatinine, and urea) using correlation and linear mixed-effects (LME) modeling.

Results

There was good agreement between manual and automated CT. Automated measures were more precise because of smaller measurement error over time. External adjudication of major discrepancies was in favor of automated measures. Significant differences were observed in the choroid pre- and posttransplant in both cohorts, and LME modeling revealed significant linear associations observed between choroidal measures and renal function in recipients. Significant associations were mostly stronger with automated CT (eGFR, P < 0.001; creatinine, P = 0.004; urea, P = 0.04) compared to manual CT (eGFR, P = 0.002; creatinine, P = 0.01; urea, P = 0.03).

Conclusions

Our automated approach has greater precision than human-performed manual measurements, which may explain stronger associations with renal function compared to manual measurements. To improve detection of meaningful associations with clinical endpoints in longitudinal studies of OCT, reducing measurement error should be a priority, and automated measurements help achieve this.

Translational Relevance

We introduce a novel choroid segmentation algorithm that can replace manual grading for studying the choroid in renal disease and other clinical conditions.

Correlation between diabetic retinopathy and diabetic nephropathy: a two-sample Mendelian randomization study

Rationale & objective

A causal relationship concerning diabetic retinopathy (DR) and diabetic nephropathy (DN) has been studied in many epidemiological observational studies. We conducted a two-sample mendelian randomization study from the perspective of genetics to assess these associations.

Methods

20 independent single nucleotide polymorphisms (SNPs) associated with diabetic retinopathy were selected from the FinnGen consortium. Summary-level data for diabetic nephropathy were obtained from the publicly available genome-wide association studies (GWAS) database, FinnGen and CKDGen consortium. Inverse variance weighted (IVW) was selected as the primary analysis. MR-Egger, weighted median (WM), simple mode and weighted mode were used as complementary methods to examine causality. Additionally, sensitivity analyses including Cochran's Q test, MR-Egger, MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO), and leave-one-out analyses were conducted to guarantee the accuracy and robustness of our MR analysis.

Results

Our current study demonstrated positive associations of genetically predicted diabetic retinopathy with diabetic nephropathy (OR=1.32; P=3.72E-11), type 1 diabetes with renal complications (OR=1.96; P= 7.11E-11), and type 2 diabetes with renal complications (OR=1.26, P=3.58E-04). Further subtype analysis and multivariate mendelian randomization (MVMR) also reached the same conclusion. A significant casualty with DN was demonstrated both in non-proliferative DR (OR=1.07, P=0.000396) and proliferative DR (OR=1.67, P=3.699068E-14). All the findings were robust across several sensitivity analyses.

Conclusion

Consistent with previous clinical studies, our findings revealed a positive correlation between DR and DN, providing genetic evidence for the non-invasive nature of DR in predicting DN.

Single-cell transcriptomes reveal a molecular link between diabetic kidney and retinal lesions

The occurrence of diabetic nephropathy (DN) and diabetic retinopathy (DR) are closely associated in patients with diabetes. However, the cellular and molecular linkage of DN and DR has not been elucidated, and further revelations are needed to improve mutual prognostic decisions and management. Here, we generate and integrate single-cell RNA sequencing profiles of kidney and retina to explore the cellular and molecular association of kidney and retina in both physiological and pathological conditions. We find renal mesangial cells and retinal pericytes share molecular features and undergo similar molecular transitions under diabetes. Furthermore, we uncover that chemokine regulation shared by the two cell types is critical for the co-occurrence of DN and DR, and the chemokine score can be used for the prognosis of DN complicated with DR. These findings shed light on the mechanism of the co-occurrence of DN and DR and could improve the prevention and treatments of diabetic microvascular complications.

Risks of Topical Carbonic Anhydrase Inhibitors in Glaucoma Patients With Chronic Kidney Disease: A Nationwide Population-Based Study

PURPOSE

To investigate the risks of metabolic acidosis and renal outcomes after topical carbonic anhydrase inhibitor (CAI) use in patients with both primary open-angle glaucoma (POAG) and advanced chronic kidney disease (CKD).

DESIGN

Nationwide, population-based cohort study.

METHODS

This study was conducted with population data from Taiwan's National Health Insurance (NHI) Research Database between January 2000 and June 2009. Patients with advanced CKD who were diagnosed with glaucoma (International Classification of Diseases, Ninth Revision [ICD-9] code 365) and had been receiving eye drops for glaucoma (including carbonic anhydrase inhibitors selected by NHI drug code) were enrolled. Using Kaplan-Meier methods, we compared the cumulative incidence of mortality, long-term dialysis, and cumulative incidence of metabolic acidosis over time between CAI users and CAI non-users. Primary outcomes comprised mortality, renal outcome (progression to hemodialysis), and metabolic acidosis.

RESULTS

In this cohort, topical CAI users had a higher incidence of long-term dialysis than non-users (incidence = 1,216.85 vs 764.17 events per 100 patient-years; adjusted hazard ratio = 1.17, 95% CI = 1.01-1.37). Hospital admissions due to metabolic acidosis were higher in CAI users compared with non-users (incidence = 21.54 vs 11.87 events per 100 patient-years; adjusted hazard ratio = 1.89, 95% CI = 1.07-3.36).

CONCLUSIONS

Topical CAIs may be associated with higher risks of long-term dialysis and metabolic acidosis in patients with POAG and pre-dialysis advanced CKD. Therefore, topical CAIs should be used with caution in advanced CKD patients.

Optic Nerve Head Capillary Network Quantified by Optical Coherence Tomography Angiography and Decline of Renal Function in Type 2 Diabetes: A Three-Year Prospective Study

PURPOSE

To assess the association of optic capillary perfusion with decline in the estimated glomerular filtration rate (eGFR) and to clarify its added value.

DESIGN

Prospective, observational cohort study.

METHODS

Patients with type 2 diabetes mellitus without diabetic retinopathy (non-DR) underwent standardized examinations annually during a 3-year follow-up period. The superficial capillary plexus (SCP), deep capillary plexus (DCP), and radial peripapillary plexus (RPC) of optic nerve head (ONH) were visualized using optical coherence tomography angiography (OCTA), and the perfusion density (PD) and vascular density were quantified for the whole image and circumpapillary regions of the ONH.  The lowest tercile of annual eGFR slope was defined as the rapidly progressive group, and the highest tercile was considered the stable group.

RESULTS

A total of 906 patients were included for 3-mm × 3-mm OCTA analysis. After adjusting for other confounders, each 1% decrease in baseline whole en face PD in SCP and RPC was associated with accelerated rates of decline in eGFR by -0.53 mL/min/1.73/m2 per year (95% confidence interval [CI] -0.17 to -0.90; P = .004) and -0.60 mL/min/1.73/m2 per year (95% CI 0.28-0.91), respectively. Adding both whole-image PD in SCP and whole-image PD in RPC to the conventional model increased the area under the curve from 0.696 (95% CI 0.654-0.737) to 0.725 (95% CI 0.685-0.765; P = .031). Another cohort of 400 eligible patients with 6-mm × 6 mm OCTA imaging validated the significant associations between ONH perfusion and rate of eGFR decline (P < .05).

CONCLUSIONS

Reduced capillary perfusion of ONH in patients with type 2 diabetes mellitus is associated with a greater eGFR decline, and it has additional predictive value for detecting an early stage and progression.

Macular Microvascular Perfusion Status in Hypertensive Patients with Chronic Kidney Disease

To compare retinal microvascular perfusion between the eyes of hypertensive patients with and without chronic kidney disease (CKD), the vessel density (VD) and fractal dimension (FD) of the superficial (SVP) and deep retinal vascular plexus (DVP) were analyzed on 6 × 6 mm fovea-centered optical coherence tomography angiography (OCTA) images of patients with hypertension. The retina was divided into an inner ring (IR) and outer ring (OR) according to the Early Treatment of Diabetic Retinopathy Study grid. The glomerular filtration rate (GFR) was determined and CKD was diagnosed (GFR < 60 mL/min/1.73 m2). Ninety-six eyes from 52 patients with hypertension were included in this analysis. Twenty patients (n = 37 eyes) were diagnosed with CKD. The mean age was 69 ± 11.7 years and 60.4 ± 9.2 years in the CKD group and in the control group, respectively. The univariate model revealed a significant difference in VD between patients without and with CKD in the superficial IR (0.36 ± 0.03 vs. 0.34 ± 0.04, p = 0.03), the superficial OR (0.35 ± 0.02 vs. 0.33 ± 0.04, p = 0.02), the deep OR (0.24 ± 0.01 vs. 0.23 ± 0.02, p = 0.003), and the FD in the SVP (1.87 ± 0.01 vs. 1.86 ± 0.02, p = 0.02) and DVP (1.83 ± 0.01 vs. 1.82 ± 0.01, p = 0.006). After adjusting for age and sex, these differences did not remain statistically significant. Similar results were observed for the FD in the SVP and DVP. In our cohort, patients with hypertension and CKD did not differ from patients without CKD in regard to microvascular perfusion status in the macular area as assessed using OCTA.

Uric acid and glaucoma: a systematic review and meta-analysis

Background

Glaucoma, the leading cause of irreversible blindness, is a common disorder that contributes to gradual optic nerve degeneration. The beneficial impacts of uric acid (UA) have been reported in some neurodegenerative conditions such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. But the results of current studies about the association between serum UA level and glaucoma are conflicting. The present meta-analysis was conducted to provide a better understanding of the association between serum UA level and glaucoma.

Methods

We searched the databases of PubMed, Scopus, Web of Science, and Google Scholar systematically until November 20, 2022 to identify case-control studies, comparing the serum UA concentrations of the patients with glaucoma and controls. The mean ± standard division difference was used to assess the difference in serum UA concentrations between the glaucoma patients and controls.

Results

Six studies involving 1,221 glaucoma patients and 1,342 control group were included in the present meta-analysis. This meta-analysis using a random effect model indicated that the mean UA level in glaucoma patients was 0.13 (I2 = 91.92%, 95% CI = -0.42 to 0.68) higher than the controls; however, it was not statistically significant.

Conclusions

Our findings provide evidence that glaucoma patients have a higher serum UA level compared to the controls, but this difference is not statistically significant. Prospective studies are needed to determine the possible association between increased UA and glaucoma pathogenesis.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022364055, identifier: CRD42022364055.

Retinal Microvascular Diameters are Associated with Diabetic Kidney Disease in Patients with Type 2 Diabetes Mellitus

Objective

To investigate the association between retinal microvascular diameters and diabetic kidney disease (DKD) in patients with type 2 diabetes mellitus (T2DM).

Methods

A total of 690 patients with T2DM were included in this retrospective study. Patients were divided into DKD and non-DKD groups according to urine microalbumin/creatinine ratio and estimated glomerular filtration rate. Retinal microvascular diameters were measured by the automated retinal image analysis system. Multivariate logistic regression analysis and restricted cubic splines were used to assess the relationships between the retinal microvascular diameters and DKD in patients with T2DM.

Results

Multivariate logistic regression showed that widened diameters of retinal venules and narrowed diameters of retinal arterioles were associated with DKD after adjusting for potential confounding variables. There was a significant linear trend between the diameters of superior temporal retinal venula (P for trend < 0.001, P for non-linearity = 0.080), inferior temporal retinal venula (P for trend < 0.001, P for non-linearity = 0.111) and central retinal venular equivalent (CRVE) (P for trend < 0.001, P for non-linearity = 0.392) and risk of DKD in patients with T2DM. The restricted cubic splines showed that narrowed retinal arteriolar diameters, superior and inferior nasal retinal venulas were associated with the risk of DKD in a non-linear fashion (all P for non-linearity < 0.001).

Conclusion

Wider retinal venular diameters and narrower retinal arteriolar diameters were associated with an increased risk of DKD in patients with T2DM. Widened retinal venular diameters, especially CRVE, superior and inferior temporal retinal venula, were positively associated with an increased risk of DKD in a linear fashion. In contrast, narrowed retinal arteriolar diameters were associated with the risk of DKD in a non-linear fashion.

Non-invasive chronic kidney disease risk stratification tool derived from retina-based deep learning and clinical factors

Despite the importance of preventing chronic kidney disease (CKD), predicting high-risk patients who require active intervention is challenging, especially in people with preserved kidney function. In this study, a predictive risk score for CKD (Reti-CKD score) was derived from a deep learning algorithm using retinal photographs. The performance of the Reti-CKD score was verified using two longitudinal cohorts of the UK Biobank and Korean Diabetic Cohort. Validation was done in people with preserved kidney function, excluding individuals with eGFR <90 mL/min/1.73 m² or proteinuria at baseline. In the UK Biobank, 720/30,477 (2.4%) participants had CKD events during the 10.8-year follow-up period. In the Korean Diabetic Cohort, 206/5014 (4.1%) had CKD events during the 6.1-year follow-up period. When the validation cohorts were divided into quartiles of Reti-CKD score, the hazard ratios for CKD development were 3.68 (95% Confidence Interval [CI], 2.88-4.41) in the UK Biobank and 9.36 (5.26-16.67) in the Korean Diabetic Cohort in the highest quartile compared to the lowest. The Reti-CKD score, compared to eGFR based methods, showed a superior concordance index for predicting CKD incidence, with a delta of 0.020 (95% CI, 0.011-0.029) in the UK Biobank and 0.024 (95% CI, 0.002-0.046) in the Korean Diabetic Cohort. In people with preserved kidney function, the Reti-CKD score effectively stratifies future CKD risk with greater performance than conventional eGFR-based methods.

Evaluation of Ocular Perfusion in Patients with End-Stage Renal Disease Receiving Hemodialysis Using Optical Coherence Tomography Angiography

Hemodialysis (HD) is known to affect ocular blood flow. This case-control study aims to evaluate macular and peripapillary vasculature in patients with end-stage renal disease (ESRD) receiving HD in comparison to matched controls. A total of 24 eyes of 24 ESRD patients receiving HD and 24 eyes of 24 healthy, age- and gender-matched control subjects were prospectively included in this study. Optical coherence tomography angiography was used to image the superficial (SCP), deep (DCP), and choriocapillary (CC) macular vascular plexus, as well as the radial peripapillary capillaries (RPC) of the optic disc. In addition, retinal thickness (RT) and retinal volume (RV) were compared between both groups. Flow density (FD) values of each retinal layer and data of parameters related to the foveal avascular zone (FAZ), as well as RT and RV, were analyzed using Mann-Whitney U tests. There was no significant difference in FAZ parameters between the two groups. Whole en face FD of the SCP and CC was noticeably reduced in the HD group in comparison to the control group. FD was negatively correlated with the duration of HD treatment. RT and RV were significantly smaller in the study group than in controls. Retinal microcirculation appears altered in patients with ESRD undergoing HD. Concurrently, the DCP appears more resilient towards hemodynamic changes in comparison to the other microvascular retinal layers. OCTA is a useful, non-invasive tool to investigate retinal microcirculation in ESRD patients.

Current progress in artificial intelligence-assisted medical image analysis for chronic kidney disease: A literature review

Chronic kidney disease (CKD) causes irreversible damage to kidney structure and function. Arising from various etiologies, risk factors for CKD include hypertension and diabetes. With a progressively increasing global prevalence, CKD is an important public health problem worldwide. Medical imaging has become an important diagnostic tool for CKD through the non-invasive identification of macroscopic renal structural abnormalities. Artificial intelligence (AI)-assisted medical imaging techniques aid clinicians in the analysis of characteristics that cannot be easily discriminated by the naked eye, providing valuable information for the identification and management of CKD. Recent studies have demonstrated the effectiveness of AI-assisted medical image analysis as a clinical support tool using radiomics- and deep learning-based AI algorithms for improving the early detection, pathological assessment, and prognostic evaluation of various forms of CKD, including autosomal dominant polycystic kidney disease. Herein, we provide an overview of the potential roles of AI-assisted medical image analysis for the diagnosis and management of CKD.

Ocular images-based artificial intelligence on systemic diseases

PURPOSE

To provide a summary of the research advances on ocular images-based artificial intelligence on systemic diseases.

METHODS

Narrative literature review.

RESULTS

Ocular images-based artificial intelligence has been used in a variety of systemic diseases, including endocrine, cardiovascular, neurological, renal, autoimmune, and hematological diseases, and many others. However, the studies are still at an early stage. The majority of studies have used AI only for diseases diagnosis, and the specific mechanisms linking systemic diseases to ocular images are still unclear. In addition, there are many limitations to the research, such as the number of images, the interpretability of artificial intelligence, rare diseases, and ethical and legal issues.

CONCLUSION

While ocular images-based artificial intelligence is widely used, the relationship between the eye and the whole body should be more clearly elucidated.

Associations of concomitant retinopathy and depression with mortality in a nationally representative population

OBJECTIVE

To evaluate the interaction effects between retinopathy and depression on mortality risks in genral population and subpopulation with diabetes.

METHODS

Prospective analyses were conducted on data from the National Health and Nutrition Examination Surveys study. Associations of retinopathy, depression and their interaction with all-cause, cardiovascular disease (CVD)-specific, cancer-specific and other-specific mortality risk were estimated using Kaplan-Meier curves and multivariate Cox proportional hazards models.

RESULTS

Among 5367 participants, the weighted prevalence of retinopathy and depression was 9.6 % and 7.1 %, respectively. After a follow-up period of 12.1 years, 1295 deaths (17.3 %) occurred. Retinopathy was associated with an increased risk of all-cause (hazard ratio [HR]; 95 % confidence interval [CI]) (1.47; 1.27-1.71), CVD-specific (1.87; 1.45-2.41), and other-specific (1.43; 1.14-1.79) mortality. Similar relationship was observed between depression and all-cause mortality (1.24; 1.02-1.52). Retinopathy and depression had a positive multiplicative and additive interaction effect on all-cause (P_interaction = 0.015; relative excess risk of interaction [RERI] 1.30; 95 % CI 0.15-2.45) and CVD-specific mortality (P_interaction = 0.042; RERI 2.65; 95 % CI -0.12-5.42). Concomitant retinopathy and depression was more markedly associated with all-cause (2.86; 1.91-4.28), CVD-specific (4.70; 2.57-8.62), and other-specific mortality risks (2.18; 1.14-4.15) compared to those without retinopathy and depression. These associations were more pronounced in the diabetic participants.

CONCLUSIONS

The co-occurrence of retinopathy and depression increases the risk of all-cause and CVD-specific mortality among middle-aged and older adults in the United States, especially in population with diabetes. Focus on diabetic patients and active evaluation and intervention of retinopathy with depression may improve their quality of life and mortality outcomes.

Association between inequalities in human resources for health and all cause and cause specific mortality in 172 countries and territories, 1990-2019: observational study

OBJECTIVE

To explore inequalities in human resources for health (HRH) in relation to all cause and cause specific mortality globally in 1990-2019.

DESIGN

Observational study.

SETTING

172 countries and territories.

DATA SOURCES

Databases of the Global Burden of Disease Study 2019, United Nations Statistics, and Our World in Data.

MAIN OUTCOME MEASURES

The main outcome was age standardized all cause mortality per 100 000 population in relation to HRH density per 10 000 population, and secondary outcome was age standardized cause specific mortality. The Lorenz curve and the concentration index (CCI) were used to assess trends and inequalities in HRH.

RESULTS

Globally, the total HRH density per 10 000 population increased, from 56.0 in 1990 to 142.5 in 2019, whereas age standardized all cause mortality per 100 000 population decreased, from 995.5 in 1990 to 743.8 in 2019. The Lorenz curve lay below the equality line and CCI was 0.43 (P<0.05), indicating that the health workforce was more concentrated among countries and territories ranked high on the human development index. The CCI for HRH was stable, at about 0.42-0.43 between 1990 and 2001 and continued to decline (narrowed inequality), from 0.43 in 2001 to 0.38 in 2019 (P<0.001). In the multivariable generalized estimating equation model, a negative association was found between total HRH level and all cause mortality, with the highest levels of HRH as reference (low: incidence risk ratio 1.15, 95% confidence interval 1.00 to 1.32; middle: 1.14, 1.01 to 1.29; high: 1.18, 1.08 to 1.28). A negative association between total HRH density and mortality rate was more pronounced for some types of cause specific mortality, including neglected tropical diseases and malaria, enteric infections, maternal and neonatal disorders, and diabetes and kidney diseases. The risk of death was more likely to be higher in people from countries and territories with a lower density of doctors, dentistry staff, pharmaceutical staff, aides and emergency medical workers, optometrists, psychologists, personal care workers, physiotherapists, and radiographers.

CONCLUSIONS

Inequalities in HRH have been decreasing over the past 30 years globally but persist. All cause mortality and most types of cause specific mortality were relatively higher in countries and territories with a limited health workforce, especially for several specific HRH types among priority diseases. The findings highlight the importance of strengthening political commitment to develop equity oriented health workforce policies, expanding health financing, and implementing targeted measures to reduce deaths related to inadequate HRH to achieve universal health coverage by 2030.

Glaucoma and Systemic Disease

Glaucoma is the leading cause of irreversible blindness in the world. Due to its potential to cause permanent vision loss, it is important to understand how systemic conditions and their respective treatments can be associated with or increase the risk for developing glaucoma. In this review, we examined the literature for up-to-date discussions and provided commentary on glaucoma, its pathophysiology, and associated risk factors. We discuss systemic diseases and the impact, risk, and mechanism for developing glaucoma, including pharmacologically induced glaucoma; inflammatory and auto-immune conditions; infectious, dermatologic, cardiovascular, pulmonary, renal, urologic, neurologic, psychiatric and systemic malignancies: intraocular tumors; as well as pediatric, and genetic conditions. The goal of our discussion of systemic conditions including their commonality, mechanisms, treatments, and associations with developing glaucoma is to emphasize the importance of ocular examinations and follow-up with the multidisciplinary teams involved in the care of each patient to prevent unnecessary vision-loss.

Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration

The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.

Rates of adverse clinical events in patients with chronic kidney disease: analysis of electronic health records from the UK clinical practice research datalink linked to hospital data

BACKGROUND

Further understanding of adverse clinical event rates in patients with chronic kidney disease (CKD) is required for improved quality of care. This study described baseline characteristics, adverse clinical event rates, and mortality risk in patients with CKD, accounting for CKD stage and dialysis status.

METHODS

This retrospective, noninterventional cohort study included data from adults (aged ≥ 18 years) with two consecutive estimated glomerular filtration rates of < 60 ml/min/1.73 m², recorded ≥ 3 months apart, from the UK Clinical Practice Research Datalink of electronic health records obtained between January 1, 2004, and December 31, 2017. Select adverse clinical events, associated with CKD and difficult to quantify in randomized trials, were assessed; defined by Read codes and International Classification of Diseases, Tenth Revision codes. Clinical event rates were assessed by dialysis status (dialysis-dependent [DD], incident dialysis-dependent [IDD], or non-dialysis-dependent [NDD]), dialysis modality (hemodialysis [HD] or peritoneal dialysis [PD]), baseline NDD-CKD stage (3a-5), and observation period.

RESULTS

Overall, 310,953 patients with CKD were included. Comorbidities were more common in patients receiving dialysis than in NDD-CKD, and increased with advancing CKD stage. Rates of adverse clinical events, particularly hyperkalemia and infection/sepsis, also increased with advancing CKD stage and were higher in patients on HD versus PD. Mortality risk during follow-up (1-5-year range) was lowest in patients with stage 3a NDD-CKD (2.0-18.5%) and highest in patients with IDD-CKD (26.3-58.4%).

CONCLUSIONS

These findings highlight the need to monitor patients with CKD for comorbidities and complications, as well as signs or symptoms of clinical adverse events.

Retinal age gap as a predictive biomarker for mortality risk

AIM

To develop a deep learning (DL) model that predicts age from fundus images (retinal age) and to investigate the association between retinal age gap (retinal age predicted by DL model minus chronological age) and mortality risk.

METHODS

A total of 80 169 fundus images taken from 46 969 participants in the UK Biobank with reasonable quality were included in this study. Of these, 19 200 fundus images from 11 052 participants without prior medical history at the baseline examination were used to train and validate the DL model for age prediction using fivefold cross-validation. A total of 35 913 of the remaining 35 917 participants had available mortality data and were used to investigate the association between retinal age gap and mortality.

RESULTS

The DL model achieved a strong correlation of 0.81 (p<0·001) between retinal age and chronological age, and an overall mean absolute error of 3.55 years. Cox regression models showed that each 1 year increase in the retinal age gap was associated with a 2% increase in risk of all-cause mortality (hazard ratio (HR)=1.02, 95% CI 1.00 to 1.03, p=0.020) and a 3% increase in risk of cause-specific mortality attributable to non-cardiovascular and non-cancer disease (HR=1.03, 95% CI 1.00 to 1.05, p=0.041) after multivariable adjustments. No significant association was identified between retinal age gap and cardiovascular- or cancer-related mortality.

CONCLUSIONS

Our findings indicate that retinal age gap might be a potential biomarker of ageing that is closely related to risk of mortality, implying the potential of retinal image as a screening tool for risk stratification and delivery of tailored interventions.

Retinal Neurodegeneration and Visual Acuity Decline in Patients with Chronic Kidney Disease

INTRODUCTION

Chronic kidney disease (CKD) has been associated with accelerated retinal neurodegeneration. The purpose of this study is to evaluate the association between retinal neurodegeneration and the best-corrected visual acuity (BCVA) decline in patients with CKD.

METHODS

Post hoc analysis of two prospective studies. Patients with CKD stage ≥ 3 were enrolled. Macular thickness, peripapillary retinal nerve fiber layer (pRNFL) thickness, and macular ganglion cell complex (GCC) thickness were measured by optical coherence tomography. Eyes were classified into three groups: Group 1, no GCC defect; Group 2, GCC defect confined to parafoveal area; and Group 3, GCC defects extending beyond the parafoveal area. Each group was matched for age, sex, axial length, lens status, and cataract grading.

RESULTS

A total of 120 eyes (40 eyes in each group) from 120 patients (age 63.0 ± 10.3 years) were included. The logMAR BCVA was 0.076 ± 0.101, 0.100 ± 0.127, and 0.196 ± 0.191 in Group 1, 2, and 3, respectively. Group 3, but not Group 2, had a significantly worse BCVA than Group 1. In simple linear regression, parafoveal inner retinal thickness, pRNFL thickness, presence of pRNFL defect, GCC thickness, GCC global loss volume, GCC focal loss volume, and GCC defect extending beyond parafoveal area were associated with BCVA. Central subfield retinal thickness (CRT), parafoveal full retinal thickness, and parafoveal outer retinal thickness were not associated with BCVA. In backward stepwise linear regression, age and GCC defects extending beyond the parafoveal area were factors associated with BCVA. Moreover, GCC defect extending beyond parafoveal area was connected with worse BCVA in both phakic and pseudophakic subgroups.

CONCLUSIONS

GCC defect extending beyond parafoveal area could be an independent biomarker associated with decreased BCVA in patients with CKD. However, macular thinning measured by CRT or parafoveal full retinal thickness might have low discriminative power in determining BCVA.

A Systematic Review of Joint Spatial and Spatiotemporal Models in Health Research

With the advancement of spatial analysis approaches, methodological research addressing the technical and statistical issues related to joint spatial and spatiotemporal models has increased. Despite the benefits of spatial modelling of several interrelated outcomes simultaneously, there has been no published systematic review on this topic, specifically when such models would be useful. This systematic review therefore aimed at reviewing health research published using joint spatial and spatiotemporal models. A systematic search of published studies that applied joint spatial and spatiotemporal models was performed using six electronic databases without geographic restriction. A search with the developed search terms yielded 4077 studies, from which 43 studies were included for the systematic review, including 15 studies focused on infectious diseases and 11 on cancer. Most of the studies (81.40%) were performed based on the Bayesian framework. Different joint spatial and spatiotemporal models were applied based on the nature of the data, population size, the incidence of outcomes, and assumptions. This review found that when the outcome is rare or the population is small, joint spatial and spatiotemporal models provide better performance by borrowing strength from related health outcomes which have a higher prevalence. A framework for the design, analysis, and reporting of such studies is also needed.

The relationship between renal function and diabetic retinopathy in patients with type 2 diabetes: A three-year prospective study

Objective

To explore the association of diabetic retinopathy (DR) and diabetic macular edema (DME) with renal function in patients with type 2 diabetes mellitus (T2DM).

Design

A prospective cohort study.

Methods

This single-centre study included patients with no DR, mild non-proliferative DR (NPDR), and no DME at baseline. DR and DME were assessed using 7-field fundus photography and swept-source OCT (SS-OCT). The baseline renal function assessed included the estimated glomerular filtration rate (eGFR) and microalbuminuria (MAU). Cox regression analyses were used to assess the hazard ratio (HR) of renal function with the progression of DR and the development of DME.

Results

A total of 1409 patients with T2DM (1409 eyes) were included. During 3 years of follow-up,143 patients had DR progression, and 54 patients developed DME. Low eGFR levels at baseline were associated with the development of DR (HR, 1.044 per 1-SD decrease; 95% CI, 1.035-1.053; P < 0.001). Compared to the participants with eGFRs >90 mL/min/1.73 m², the participants with eGFRs of 60-90 mL/min/1.73 m² (HR, 1.649; 95% CI, 1.094-2.485; P = 0.017) or < 60 mL/min/1.73 m² (HR, 2.106; 95% CI, 1.039-4.269; P = 0.039) had a higher risk of DR progression. Increasing MAU tertiles were associated with progression of DR (Tertile 2: HR, 2.577; 95% CI, 1.561-4.256; P < 0.001; Tertile 3: HR, 3.135; 95% CI, 1.892-5.194; P < 0.001). No significant relationship was found between renal function and the development of DME (P > 0.05).

Conclusions

Abnormal renal profiles (i.e., low levels of eGFR and high levels of MAU) were associated with the progression of DR, but not with the development of DME.

Prognostic factors for the development and progression of proliferative diabetic retinopathy in people with diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is characterised by neurovascular degeneration as a result of chronic hyperglycaemia. Proliferative diabetic retinopathy (PDR) is the most serious complication of DR and can lead to total (central and peripheral) visual loss. PDR is characterised by the presence of abnormal new blood vessels, so-called "new vessels," at the optic disc (NVD) or elsewhere in the retina (NVE). PDR can progress to high-risk characteristics (HRC) PDR (HRC-PDR), which is defined by the presence of NVD more than one-fourth to one-third disc area in size plus vitreous haemorrhage or pre-retinal haemorrhage, or vitreous haemorrhage or pre-retinal haemorrhage obscuring more than one disc area. In severe cases, fibrovascular membranes grow over the retinal surface and tractional retinal detachment with sight loss can occur, despite treatment. Although most, if not all, individuals with diabetes will develop DR if they live long enough, only some progress to the sight-threatening PDR stage.  OBJECTIVES: To determine risk factors for the development of PDR and HRC-PDR in people with diabetes and DR.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 5), Ovid MEDLINE, and Ovid Embase. The date of the search was 27 May 2022. Additionally, the search was supplemented by screening reference lists of eligible articles. There were no restrictions to language or year of publication.  SELECTION CRITERIA: We included prospective or retrospective cohort studies and case-control longitudinal studies evaluating prognostic factors for the development and progression of PDR, in people who have not had previous treatment for DR. The target population consisted of adults (≥18 years of age) of any gender, sexual orientation, ethnicity, socioeconomic status, and geographical location, with non-proliferative diabetic retinopathy (NPDR) or PDR with less than HRC-PDR, diagnosed as per standard clinical practice. Two review authors independently screened titles and abstracts, and full-text articles, to determine eligibility; discrepancies were resolved through discussion. We considered prognostic factors measured at baseline and any other time points during the study and in any clinical setting. Outcomes were evaluated at three and eight years (± two years) or lifelong.  DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data from included studies using a data extraction form that we developed and piloted prior to the data collection stage. We resolved any discrepancies through discussion. We used the Quality in Prognosis Studies (QUIPS) tool to assess risk of bias. We conducted meta-analyses in clinically relevant groups using a random-effects approach. We reported hazard ratios (HR), odds ratios (OR), and risk ratios (RR) separately for each available prognostic factor and outcome, stratified by different time points. Where possible, we meta-analysed adjusted prognostic factors. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.   MAIN RESULTS: We screened 6391 records. From these, we identified 59 studies (87 articles) as eligible for inclusion. Thirty-five were prospective cohort studies, 22 were retrospective studies, 18 of which were cohort and six were based on data from electronic registers, and two were retrospective case-control studies. Twenty-three studies evaluated participants with type 1 diabetes (T1D), 19 with type 2 diabetes (T2D), and 17 included mixed populations (T1D and T2D). Studies on T1D included between 39 and 3250 participants at baseline, followed up for one to 45 years. Studies on T2D included between 100 and 71,817 participants at baseline, followed up for one to 20 years. The studies on mixed populations of T1D and T2D ranged from 76 to 32,553 participants at baseline, followed up for four to 25 years.  We found evidence indicating that higher glycated haemoglobin (haemoglobin A1c (HbA1c)) levels (adjusted OR ranged from 1.11 (95% confidence interval (CI) 0.93 to 1.32) to 2.10 (95% CI 1.64 to 2.69) and more advanced stages of retinopathy (adjusted OR ranged from 1.38 (95% CI 1.29 to 1.48) to 12.40 (95% CI 5.31 to 28.98) are independent risk factors for the development of PDR in people with T1D and T2D. We rated the evidence for these factors as of moderate certainty because of moderate to high risk of bias in the studies.  There was also some evidence suggesting several markers for renal disease (for example, nephropathy (adjusted OR ranged from 1.58 (95% CI not reported) to 2.68 (2.09 to 3.42), and creatinine (adjusted meta-analysis HR 1.61 (95% CI 0.77 to 3.36)), and, in people with T1D, age at diagnosis of diabetes (< 12 years of age) (standardised regression estimate 1.62, 95% CI 1.06 to 2.48), increased triglyceride levels (adjusted RR 1.55, 95% CI 1.06 to 1.95), and larger retinal venular diameters (RR 4.28, 95% CI 1.50 to 12.19) may increase the risk of progression to PDR. The certainty of evidence for these factors, however, was low to very low, due to risk of bias in the included studies, inconsistency (lack of studies preventing the grading of consistency or variable outcomes), and imprecision (wide CIs). There was no substantial and consistent evidence to support duration of diabetes, systolic or diastolic blood pressure, total cholesterol, low- (LDL) and high- (HDL) density lipoproteins, gender, ethnicity, body mass index (BMI), socioeconomic status, or tobacco and alcohol consumption as being associated with incidence of PDR. There was insufficient evidence to evaluate prognostic factors associated with progression of PDR to HRC-PDR.  AUTHORS' CONCLUSIONS: Increased HbA1c is likely to be associated with progression to PDR; therefore, maintaining adequate glucose control throughout life, irrespective of stage of DR severity, may help to prevent progression to PDR and risk of its sight-threatening complications. Renal impairment in people with T1D or T2D, as well as younger age at diagnosis of diabetes mellitus (DM), increased triglyceride levels, and increased retinal venular diameters in people with T1D may also be associated with increased risk of progression to PDR. Given that more advanced DR severity is associated with higher risk of progression to PDR, the earlier the disease is identified, and the above systemic risk factors are controlled, the greater the chance of reducing the risk of PDR and saving sight.

Epidemiology of Common Ocular Manifestations among Patients on Haemodialysis in West Bank, Palestine

Objectives

This study aimed to assess the prevalence of ocular manifestations and associated factors in patients on haemodialysis.

Methods

A cross-sectional study of patients on haemodialysis from a haemodialysis unit in Nablus, Palestine, was conducted. Medical examination for ocular manifestations (intraocular pressure, cataract, retinal changes and optic neuropathy) was performed using Tono-Pen, portable slit-lamp and indirect ophthalmoscope. Predictor variables were age, gender, smoking, medical comorbidities (diabetes, hypertension, ischaemic heart disease [IHD], peripheral arterial disease [PAD]) and use of antiplatelet or anti-coagulation medications.

Results

A total of 191 patients were included in this study. The prevalence of any ocular manifestation in at least one eye was 68%. The most common ocular manifestations were retinal changes (58%) and cataract (41%). The prevalence of non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR) and NPDR or PDR was 51%, 16% and 65%. Two patients had PDR in one eye and NPDR in the other, and therefore, they were counted only once making the total for this category 71 rather than 73 patients. An increase in age by one year increased the odds of having cataract by 1.10 (95% confidence interval [CI] = 1.06-1.14). Patients with diabetes had higher odds of having cataract (odds ratio [OR] = 7.43, 95% CI: 3.26-16.95) and any retinal changes (OR = 109.48, 95% CI: 33.85-354.05) than patients without diabetes. Patients with diabetes and IHD or PAD had higher odds of having NPDR than those with diabetes without IHD or PAD (OR = 7.62, 95% CI: 2.07-28.03).

Conclusion

Retinal changes and cataract are common ocular manifestations among patients on haemodialysis. The findings emphasise the importance of periodic screening for ocular problems in this vulnerable population, especially older patients and those with diabetes, to prevent visual impartment and associated disability.

Evaluation of subclinical changes in recently diagnosed pediatric hypertension patients without hypertensive retinopathy: an OCT study

PURPOSE

To investigate subclinical choroidal and retinal changes in recently diagnosed pediatric hypertension (HT) patients.

METHODS

This prospective case-control study consisted of 62 treatment naive HT patients (34 essential HT and 28 renal-induced HT) and 62 control subjects aged 10-16 years. All demographic data and ocular parameters were noted. Macula and choroid measurements were acquired by spectral domain optical coherence tomography (SD-OCT). Choroidal measurements were obtained by taking the mean of the measurements taken from 3 nasal and 3 temporal locations at 500µ intervals (mean nasal, mean temporal) in addition to the subfoveal area.

RESULTS

All choroidal thickness (ChT) values in HT subjects were significantly lower than in the healthy group (p < 0.001 for all). Also, there was no statistically significant difference between central macular thickness (CMT) and mean macular thickness (MMT) between the two groups. Subfoveal ChT, mean ChT, and CMT values were statistically lower in patients with renal-induced HT compared to essential HT subjects (p < 0.001, p = 0.04, p = 0.014, respectively). No significant correlation was observed between choroidal thicknesses and blood pressure values in essential and renal HT groups except weak correlation between mean temporal ChT and systolic blood pressure (SBP) in renal HT group (r =  - 0.464, p ₌ 0.013).

CONCLUSION

This study demonstrated that choroidal thickness decreased even during the subclinical period in treatment naive pediatric HT subjects. In addition, it has been shown that the choroid is more affected in renal-induced HT compared to essential HT group.

Increased end-stage renal disease risk in age-related macular degeneration: a nationwide cohort study with 10-year follow-up

Common etiologies between age-related macular degeneration (AMD) and kidney disease advocate a close link between AMD and end-stage renal disease (ESRD). However, the risk of ESRD in people with AMD was not reported. Here, we investigated the association between AMD and the risk of ESRD by using a nationwide, population-based cohort data in Korea. 4,206,862 participants aged 50 years or older were categorized by presence of AMD and visual disability. Risk of ESRD was the primary outcome. Cox regression hazard model was used to examine the hazard ratios (HRs) with adjustment for potential confounders. Stratified analyses by age, sex, baseline kidney function, and cardiometabolic comorbidities were performed. During the mean 9.95 years of follow-up, there were 21,759 incident ESRD events (0.52%). AMD was associated with 33% increased risk of ESRD (adjusted HR [aHR] 1.33, 95% confidence interval [CI] 1.24-1.44), and the risk was even higher when accompanied by visual disability (aHR 2.05, 95% CI 1.68-2.50) than when not (aHR 1.26, 95% CI 1.17-1.37). Age, baseline kidney function, and cardiometabolic comorbidities significantly interact between AMD and the risk of ESRD. Our findings have clinical implications on disease prevention and risk factor management of ESRD in patients with AMD.

Co-occurrence of chronic kidney disease and glaucoma: Epidemiology and etiological mechanisms

As the histology, physiology, and pathophysiology of eyes and kidneys show substantial overlap, it has been suggested that eye and kidney diseases, such as glaucoma and chronic kidney disease (CKD), may be closely interlinked. We review the relationship between CKD and various subtypes of glaucoma, including primary open-angle glaucoma, primary angle- closure glaucoma, normal tension glaucoma, pseudoexfoliation syndrome, and several glaucoma endophenotypes. We also discuss the underlying pathogenic mechanisms and common risk factors for CKD and glaucoma, including atherosclerosis, the renin-angiotensin system, genes and genetic polymorphisms, vitamin D deficiency, and erythropoietin. The prevalence of glaucoma appears elevated in CKD patients, and vice versa, and the literature points to many intriguing associations; however, the associations are not always confirmed, and sometimes apparently opposite observations are reported. Glaucoma and CKD are complex diseases, and their mutual influence is only partially understood.

Investigations of Renal Function and Age-Related Macular Degeneration Phenotypes

PURPOSE

To investigate potential associations between renal function and age-related macular degeneration (AMD) features as assessed with multimodal retinal imaging.

METHODS

A subset of participants included in a dark adaptation study with varying AMD severities had estimated glomerular filtration rate (eGFR) values (mL/min/1.73 m2) obtained from renal function laboratory testing of serum creatinine and cystatin C. Multimodal imaging from visit dates associated with serum samples was graded by the Wisconsin Reading Center for AMD features. Associations of eGFR with AMD features and severity grades, age, smoker status and rod-intercept time were investigated. Simple univariate analyses, age-corrected multivariate analyses, and a feature-selecting least absolute shrinkage and selection operator regression were performed for eGFR as a continuous dependent variable.

RESULTS

A total of 110 patients (mean age, 75.1 ± 9.4 years; mean eGFR, 70.7 ± 18.2 mL/min/1.73 m2) were included. In univariate analyses age (estimate, -1.16 units/year; 95% confidence interval [CI], -1.46 to -0.87; P < 0.0001), rod-intercept time (estimate, -0.54 units/minute; 95% CI, -0.81 to -0.27; P < 0.001) and subretinal drusenoid deposits (-11.12 units for subretinal drusenoid deposit presence in either eye; 95% CI, -20.23 to -2.01; P = 0.017) were associated with decreased renal function. However, in age-corrected multivariate models, age was the only significant variable associated with renal function, confirmed by least absolute shrinkage and selection operator regression.

CONCLUSIONS

Accounting for age, renal function parameters did not show an association with AMD features.

TRANSLATIONAL RELEVANCE

Bruch's membrane of the eye and the glomerular basement membrane of the kidney share physiologic similarities such that decreased renal function may demonstrate associations with AMD phenotypes.

Chronic kidney disease and its association with cataracts-A cross-sectional and longitudinal study

Introduction

We aim to explore the association between chronic kidney disease (CKD) and cataracts.

Methods

A total of 121,380 participants with adequate information collected from 29 community-based recruitment centers since 2008 were analyzed. The association between CKD and self-reported diagnosed cataracts was examined in a cross-sectional cohort and was validated in a longitudinal cohort of 25,263 participants without cataracts at baseline.

Results and discussion

Of all participants, cataracts occurred in 503/1,947 (26%) and 10,464/119,433 (9%) subjects in the CKD and non-CKD groups, respectively. Multivariate logistic regression showed that CKD was significantly associated with a higher prevalence of self-reported diagnosed cataracts. In the validation cohort, a higher incidence of cataracts was also noted in the CKD group (65/317, 21%) compared to the non-CKD group (1,964/24,252, 8%) during a mean 47-month follow-up. After adjusting for confounders, subjects with CKD had a 1.498-fold higher risk of incident cataracts than those without CKD (95% confidence interval = 1.114 to 2.013, p value = 0.007). We found that CKD was associated with a higher prevalence of cataracts as well as incident cataracts, which suggests CKD patients and their primary physicians should be aware of this disease and can provide a clue for further exploration of the possible mechanisms and treatments.