A deep learning system for retinal vessel calibre improves cardiovascular risk prediction in Asians with chronic kidney disease.

Backgraund: Cardiovascular disease (CVD) and mortality is elevated in chronic kidney disease (CKD). Retinal vessel calibre in retinal photographs is associated with cardiovascular risk and automated measurements may aid CVD risk prediction. Methods: Retrospective cohort study of 860 Chinese, Malay and Indian participants aged 40-80 years with CKD [estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2] who attended the baseline visit (2004-2011) of the Singapore Epidemiology of Eye Diseases Study. Retinal vessel calibre measurements were obtained by a deep learning system (DLS). Incident CVD [non-fatal acute myocardial infarction (MI) and stroke, and death due to MI, stroke and other CVD] in those who were free of CVD at baseline was ascertained until 31 December 2019. Risk factors (established, kidney, and retinal features) were examined using Cox proportional hazards regression models. Model performance was assessed for discrimination, fit, and net reclassification improvement (NRI). Results: Incident CVD occurred in 289 (33.6%) over mean follow-up of 9.3 (4.3) years. After adjusting for established cardiovascular risk factors, eGFR [adjusted HR 0.98 (95% CI: 0.97-0.99)] and retinal arteriolar narrowing [adjusted HR 1.40 (95% CI: 1.17-1.68)], but not venular dilation, were independent predictors for CVD in CKD. The addition of eGFR and retinal features to established cardiovascular risk factors improved model discrimination with significantly better fit and better risk prediction according to the low (<15%), intermediate (15-29.9%), and high (30% or more) risk categories (NRI 5.8%), and with higher risk thresholds (NRI 12.7%). Conclusions: Retinal vessel calibre measurements by DLS were significantly associated with incident CVD independent of established CVD risk factors. Addition of kidney function and retinal vessel calibre parameters may improve CVD risk prediction among Asians with CKD.

Circulating Metabolites and Cardiovascular Disease in Asians with Chronic Kidney Disease.

INTRODUCTION: Chronic kidney disease (CKD) is a growing public health problem, with significant burden of cardiovascular disease and mortality. The risk of cardiovascular disease in CKD is elevated beyond that predicted by traditional cardiovascular risk factors, suggesting that other factors may account for this increased risk. Through metabolic profiling, this study aimed to investigate the associations between serum metabolites and prevalent cardiovascular disease in Asian patients with CKD to provide insights into the complex interactions between metabolism, cardiovascular disease and CKD. METHODS: This was a single-center cross-sectional study of 1,122 individuals from three ethnic cohorts in the population-based Singapore Epidemiology of Eye Disease (SEED) study (153 Chinese, 262 Indians, and 707 Malays) aged 40-80 years with CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2). Nuclear magnetic resonance spectroscopy was used to quantify 228 metabolites from the participants' serum or plasma. Prevalent cardiovascular disease was defined as self-reported myocardial infarction, angina, or stroke. Multivariate logistic regression identified metabolites independently associated with cardiovascular disease in each ethnic cohort. Metabolites with the same direction of association with cardiovascular disease in all three cohorts were selected and subjected to meta-analysis. RESULTS: Cardiovascular disease was present in 275 (24.5%). Participants with cardiovascular disease tend to be male; of older age; with hypertension, hyperlipidemia, and diabetes; with lower systolic and diastolic blood pressure (BP); lower high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol than those without cardiovascular disease. After adjusting for age, sex, systolic BP, diabetes, total cholesterol, and HDL cholesterol, 10 lipoprotein subclass ratios and 6 other metabolites were significantly associated with prevalent cardiovascular disease in at least one cohort. Meta-analysis with Bonferroni correction for multiple comparisons found that lower tyrosine, leucine, and valine concentrations and lower cholesteryl esters to total lipid ratio in intermediate-density lipoprotein (IDL) were associated with cardiovascular disease. CONCLUSION: In Chinese, Indian, and Malay participants with CKD, prevalent cardiovascular disease was associated with tyrosine, leucine, valine, and cholesteryl esters to total lipid ratios in IDL. Increased cardiovascular risk in CKD patients may be contributed by altered amino acid and lipoprotein metabolism. The presence of CKD and ethnic differences may affect interactions between metabolites in health and disease, hence greater understanding will allow us to better risk stratify patients, and also individualize care with consideration of ethnic disparities.

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.

The use of medium cutoff dialyzers in patients with multiple myeloma and acute kidney injury requiring hemodialysis: A systematic review.

BACKGROUND: Patients with multiple myeloma and high serum levels of circulating free light chains (FLC) have increased risk of acute kidney injury (AKI) secondary to cast nephropathy and is associated with poor survival. Despite removal of FLC by medium cutoff (MCO) dialyzer, the role of MCO hemodialysis (HD) in the treatment of cast nephropathy and its clinical benefits remain unknown. METHODS: A systematic review was conducted to establish the effectiveness of MCO dialyzer and clinical outcomes, compared to other forms of dialyzers in the removal of FLC, in myeloma patients with AKI. The primary outcome was effectiveness of MCO-HD in reducing serum FLC. The secondary outcomes were HD independence, estimated glomerular filtrate rate, mortality rates, length of hospitalization, rebound of serum FLC before the next dialysis, removal of other molecules during dialysis, and adverse events. RESULTS: We identified three case series, with a total of 17 patients. There were no randomized controlled trials (RCTs) or cohort studies. These case series showed that MCO dialyzer was effective in the removal of FLC and led to a reduction in FLC concentration post-dialysis. The majority of the case series did not have comparator arm and renal and/or other clinical outcomes. CONCLUSION: MCO dialyzer appeared to be effective in the removal of FLC based on the existing limited data. However, more data, particularly large-scale RCTs, are needed to assess the use of MCO dialyzer in reducing serum FLC and its effect on clinical outcomes in patients with multiple myeloma and AKI.

COVID-19 vaccination in systemic lupus erythematosus: a systematic review of its effectiveness, immunogenicity, flares and acceptance.

OBJECTIVES: COVID-19 infection is associated with significant morbidity in systemic lupus erythematosus but is potentially preventable by vaccination, although the impact of the myriad vaccines among SLE patients is not established. We aimed to assess the effectiveness, efficacy, acceptance and safety of COVID-19 vaccination in SLE. METHODS: We performed a systematic review of PubMed, EMBASE, CENTRAL, and Scopus publications until 8 June 2022 without language, publication year or publication status restrictions. Reports with fewer than 5 patients or incomplete information on study outcomes were excluded. Risk of bias was assessed, and results reported according to the PRISMA 2020 guidelines. RESULTS: We identified 32 studies (34 reports) comprising 8269 individuals with SLE. Post-vaccine COVID-19 infections ranged from 0 to 17% in 6 studies (5065 patients), while humoral and cellular immunogenicity was evaluated in 17 studies (976 patients) and 5 studies (112 patients), respectively. The pooled seropositivity rate was 81.1% (95% CI: 72.6, 88.5%, I2 = 85%, P < 0.01), with significant heterogeneity and higher rates for mRNA vaccines compared with non-mRNA vaccines. Adverse events and specifically lupus flares were examined in 20 studies (3853 patients) and 13 studies (2989 patients), respectively. Severe adverse events and moderate to severe lupus flares were infrequent. The pooled vaccine acceptance rate was 67.0% (95% CI: 45.2, 85.6%, I2=98%, P < 0.01) from 8 studies (1348 patients), with greater acceptance in older patients. CONCLUSION: Among SLE patients, post-vaccine COVID-19 infections, severe flares, and adverse events were infrequent, while pooled seropositivity and acceptance were high, with significant heterogeneity. These results may inform shared decision-making on vaccination during the ongoing COVID-19 pandemic. TRIAL REGISTRATION: PROSPERO, https://www.crd.york.ac.uk/PROSPERO/, CRD42021233366.

Non-steroidal anti-inflammatory drugs in chronic kidney disease and risk of acute adverse kidney events according to route of administration.

BACKGROUND: Topical non-steroidal anti-inflammatory drugs (NSAIDs) have lower risks for cardiovascular disease and gastrointestinal adverse effects compared to oral NSAIDs, but there are little data regarding their kidney risks in chronic kidney disease (CKD). We evaluated the risk of adverse acute kidney outcomes in CKD according to route of NSAID administration. METHODS: Retrospective cohort study of adults with CKD (eGFR less than 60 ml/min/1.73 m2) who received prescriptions between 2015 and 2017 from a major healthcare cluster in Singapore. The adverse acute kidney outcomes were acute kidney injury (AKI) and need for nephrology specialist consult within 30 days. RESULTS: Among 6298 adults with CKD (mean age 72.1 ± 13.3 years and eGFR 41.9 ± 12.2 ml/min/1.73 m2), systemic and topical NSAIDs were prescribed in 16.7% and 32.0%, respectively. Incident AKI (any severity), KDIGO Stage 2 or 3 AKI, and need for nephrology specialist consult occurred in 16.7%, 2.6%, and 10.6% of the study cohort, respectively. After adjusting for age, diabetes, recent cardiovascular hospitalization, baseline eGFR, RAAS blocker and diuretic, systemic NSAIDs, and topical NSAIDs, compared with the no-NSAID group, were independently associated with incident AKI [adjusted OR 1.77 (95% CI 1.46-2.15) and 1.38 (1.18-1.63), respectively]. Moderate and severe AKI (adjusted OR 1.68, 95% CI 1.09-2.58, p = 0.02) and need for nephrology consults (adjusted OR 1.41, 95% CI 1.09-1.82, p = 0.008) were also increased in systemic NSAIDs. CONCLUSION: Among adults with CKD, both systemic and topical NSAIDs were independently associated with acute adverse kidney outcomes.

Impact of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) GFR Estimating Equations on CKD Prevalence and Classification Among Asians.

Background: In 2021, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) validated a new equation for estimated glomerular filtration rate (eGFR). However, this new equation is not ethnic-specific, and prevalence of CKD in Asians is known to differ from other ethnicities. This study evaluates the impact of the 2009 and 2021 creatinine-based eGFR equations on the prevalence of CKD in multiple Asian cohorts. Methods: Eight population-based studies from China, India, Russia (Asian), Singapore and South Korea provided individual-level data (n = 67,233). GFR was estimated using both the 2009 CKD-EPI equation developed using creatinine, age, sex, and race (eGFRcr [2009, ASR]) and the 2021 CKD-EPI equation developed without race (eGFRcr [2021, AS]). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m2 (G3-G5). Prevalence of eGFR categories was compared within each study and within subgroups of age, sex, body mass index (BMI), diabetes, and hypertension status. The extent of reclassification was examined using net reclassification improvement (NRI). Findings: Of 67,233 adults, CKD prevalence was 8.6% (n = 5800/67,233) using eGFRcr (2009, ASR) and 6.4% (n = 4307/67,233) using eGFRcr (2021, AS). With the latter, CKD prevalence was reduced across all eight studies, ranging from -7.0% (95% CI -8.5% to -5.4%) to -0.4% (-1.3% to 0.5%), and across all subgroups except those in the BMI < 18.5% subgroup. Net reclassification index (NRI) was significant at -2.33% (p < 0.001). No individuals were reclassified as a higher (more severe) eGFR category, while 1.7%-4.2% of individuals with CKD were reclassified as one eGFR category lower when eGFRcr (2021, AS) rather than eGFRcr (2009, ASR) was used. Interpretation: eGFRcr (2021, AS) consistently provided reduced CKD prevalence and higher estimation of GFR among Asian cohorts than eGFRcr (2009, ASR). Based on current risk-stratified approaches to CKD management, more patients reclassified to lower-risk GFR categories could help reduce inappropriate care and its associated adverse effects among Asian renal patients. Comparison of both equations to predict progression to renal failure or adverse outcomes using prospective studies are warranted. Funding: National Medical Research Council, Singapore.

Native kidney biopsies in older adults: disease spectrum, long-term kidney and patient survival and safety.

PURPOSE: Patients undergoing kidney biopsy are increasingly older. We aimed to evaluate the clinical utility of kidney biopsy, long-term clinical outcomes, and safety of high-risk biopsies in older adults undergoing kidney biopsy in a multi-ethnic Southeast Asian cohort. METHODS: We performed a single-center retrospective study of older patients (age ≥ 60 years) who underwent native kidney biopsies between June 2011 and March 2015. The primary long-term outcome of interest was a composite of ESKD or death. The safety outcome of interest was post-biopsy bleeding in the high-risk subgroup, defined by serum creatinine > 150 µmol/l. RESULTS: Older adults accounted for 153 of 545 (28.1%) native renal biopsies performed. The median age of these older adults was 66.6 (IQR 63.0, 70.6) years. Kidney dysfunction was frequent and severe in this cohort, with 41.2% having eGFR < 30 ml/min/m2 and 71.2% having nephrotic-range proteinuria at presentation. A significant proportion (124 patients; 81.0%) had treatable diagnoses. Of these, 90 (72.6%) received immunosuppressive therapy. On Kaplan-Meier analysis, patients with pauci-immune glomerulonephritis (p = 0.004) and diabetic nephropathy (p = 0.005) were at a significantly increased risk of the composite outcome of ESKD or death. On multivariate analysis, older age and lower eGFR were independently associated with ESKD or death and ESKD alone. Lupus nephritis and diabetic nephropathy were independently associated with ESKD or death, while immunosuppressant therapy was associated with reduced ESKD alone. In the high-risk subgroup, post-biopsy bleeding occurred in 19 (22.8%) patients. Desmopressin use was not associated with reduced bleeding complications. CONCLUSION: Our study confirmed the utility of kidney biopsy in older adult patients for diagnosis and management, although risk counselling and close monitoring for bleeding complications is necessary.

Complications of Percutaneous Kidney Allograft Biopsy: Systematic Review and Meta-analysis.

BACKGROUND: Kidney biopsy is important to guide the management of allograft dysfunction but has a risk of complications. This review aimed to determine the incidence and risk factors of complications after kidney allograft biopsy. METHODS: This is a systematic review and meta-analysis of randomized controlled trials, cohort studies, or case-control studies indexed on PubMed, Embase, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry, and ClinicalTrials.gov, limited to the English language, from January 2000 to December 2020, including adult and pediatric kidney allograft biopsies. Primary outcomes were gross hematuria, bleeding requiring transfusion, and major complications (requiring interventions such as blood transfusion or surgical or radiological interventions). RESULTS: The review included 72 studies (40 082 biopsies). The quality of included studies was suboptimal. Pooled rates of gross hematuria, bleeding requiring transfusion, and major complications were 3.18% [95% confidence interval (95% CI), 2.31-4.19], 0.31% (95% CI, 0.15-0.52) and 0.89% (95% CI, 0.61-1.22), respectively. Gross hematuria rates were lower in high-income compared with middle-income countries (2.59% versus 6.44%, P < 0.01) and biopsies performed by radiology as compared with nephrology departments (1.25% versus 3.71%, P < 0.01). Blood transfusion rates were lower in pediatrics than adults (0.0% versus 0.65%, P < 0.01). Major complications were lower in biopsies performed by specialists as compared with trainees (0.02% versus 3.64%, P < 0.01). Graft loss and mortality were extremely rare. Limitations included missing data, few randomized controlled trials, and possible publication bias. CONCLUSIONS: The risk of complications after kidney allograft biopsy was low. Given the low quality of included studies, risk factors for complications should be further examined in future studies.

A Descriptive Evaluation of Health Literacy and Determinants of COVID-19 Vaccine Acceptance among Patients with IgA Nephropathy with High Vaccine Uptake.

Aims: Shared decision-making regarding COVID-19 vaccination in IgA nephropathy involves the ability to handle health information regarding potential benefits and risk of flare, but few studies have evaluated health literacy in the context of vaccination. We aimed to evaluate the health literacy and COVID-19 vaccination uptake and acceptance in IgA nephropathy. Methods: Single-center cross-sectional study of 126 consecutive patients with IgA nephropathy. Health literacy was assessed using the HLS-EU-47 questionnaire. Determinants of vaccine acceptance such as contextual influences, individual and group influences, and vaccine-specific issues were adapted from the World Health Organization framework. Results: Forty-eight patients (38.1%) with IgAN nephropathy completed the survey between June and August 2021. The participants' median age was 40.5 (31.6, 52.8) years with median disease duration of 2.8 (1.3, 4.3) years. The median general health literacy index was 31.74 (29.88, 35.82) with significantly greater difficulty in the competency of appraising health information and in the domain of disease prevention (p < 0.001). Forty-five patients (93.8%) received at least one dose of COVID-19 vaccine between January and August 2021. Among the 3 unvaccinated patients, 2 intended to receive the vaccination while and 1 did not intend to get vaccinated. There was a high level of trust and belief that their government and healthcare providers had their best interests at heart and that the healthcare providers were honest about the vaccine's risk and benefits, although 31.2% did not understand how the vaccine works and 22.9% believed that there were other ways to prevent infection. Most thought there was adequate safety information, were confident in the system for tracking adverse events and had no issues with access to the vaccine. Conclusion: Participants with IgA nephropathy had high health literacy scores and low vaccine hesitancy. The determinants for vaccine acceptance can potentially guide efforts to optimize vaccination coverage.