A retrospective cohort study predicting and validating impact of the COVID-19 pandemic in individuals with chronic kidney disease

Association between pre-existing cardiovascular risk factors and post-acute sequelae of COVID-19 in older adults

BACKGROUND

The long-term health impacts of COVID-19, including post-acute sequelae of SARS-CoV-2, remain insufficiently explored, especially concerning pre-existing cardiovascular risk factors in older adults. This study examines the association between these risk factors and post-acute sequelae of SARS-CoV-2 in this population.

METHODS

A retrospective study of Brazilian adults aged = 60 years assessed the persistence of post-acute sequelae of SARS-CoV-2 three months after infection in 2020. Cardiovascular risk factors (obesity, smoking, high blood pressure, diabetes mellitus, hypercholesterolemia, and chronic kidney disease) were analyzed in relation to sequelae and adjusting for sociodemographic variables. Data were obtained from the Department of Epidemiological Surveillance in Roraima, Brazil.

RESULTS

Of the 1,322 participants (55% female; mean age 70.4 years, SD = 7.87), 61.7% (95% CI: 59.1-63.9) reported at least one post-acute sequelae of SARS-CoV-2 at the three-month follow-up. The likelihood of post-acute sequelae of SARS-CoV-2 was significantly higher in participants with diabetes mellitus (OR = 4.39; 95% CI: 3.42-5.66), tobacco use (OR = 3.93; 95% CI: 2.47-6.23), hypertension (OR = 3.62; 95% CI: 2.73-4.78), or hypercholesterolemia (OR = 3.58; 95% CI: 2.80-4.59). Chronic kidney disease (OR = 2.28; 95% CI: 1.59-3.25) and obesity (OR = 1.83; 95% CI: 1.28-2.61) were less strongly associated.

CONCLUSIONS

Pre-existing cardiovascular risk factors are linked to a higher likelihood of long-term COVID-19 sequelae in adults aged = 60 years old. Preventing and managing these factors are crucial for reducing the long-term effects of COVID-19, particularly during a pandemic.

Predictors of COVID-19 Readmission Among Patients Previously Hospitalized for SARS-CoV-2

INTRODUCTION

Predictors of coronavirus disease 2019 (COVID-19)-related rehospitalization remain underexplored. This study aims to identify the main risk factors associated with rehospitalizations due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfections among residents of Lombardy, northern Italy.

METHODS

A retrospective observational study was conducted using two linked administrative databases covering demographic data, comorbidities, hospital records, and COVID-19 data of Lombardy residents. The study population included patients hospitalized for COVID-19 between February 2020 and August 2021. Rehospitalization was defined as a second COVID-19-related hospitalization occurring at least 90 days after the first admission. The Fine-Gray subdistribution hazard model was used to identify risk factors, accounting for death as a competing risk.

RESULTS

Out of 98,369 patients hospitalized for COVID-19 between February 1, 2020 and August 31, 2021, 72,593 were alive 90 days after admission and 610 of these (0.8%) were rehospitalized. A higher rehospitalization risk was observed in older male patients with multiple comorbidities. Renal failure, liver disease, and use of diuretics were significantly associated with rehospitalization risk, while female biological sex and the use of lipid-lowering drugs were associated with a lower risk.

CONCLUSIONS

This is the first study conducted on regional administrative databases to investigate COVID-19 rehospitalizations. Through the availability of a huge cohort, it provides a groundwork for optimizing care for individuals at higher risk for COVID-19-related rehospitalizations. It underlines the need for patient-management approaches that extend beyond the initial recovery. This stresses the importance of ongoing monitoring and personalized interventions for those at heightened risk not only of SARS-CoV-2 reinfection but also related rehospitalizations.

Dialysis parameters associated with SARS-CoV-2 infection and prognosis in end-stage kidney disease

BACKGROUND

The Covid-19 pandemic has affected patients with end-stage kidney disease (ESKD). Whether dialysis parameters have a prognostic value in ESKD patients with Covid-19 remains unclear.

MATERIALS AND METHODS

We retrospectively evaluated clinical characteristics, blood pressure (BP) and dialysis parameters in ESKD patients undergoing maintenance outpatient hemodialysis, with (Covid-ESKD) and without (No-Covid-ESKD) Covid-19, at four Brazilian hemodialysis facilities. The Covid-ESKD (n = 107; 54% females; 60.8 ± 17.7 years) and No-Covid-ESKD (n = 107; 62% females; 58.4 ± 14.6 years) groups were matched by calendar time. The average BP and dialysis parameters were calculated during the pre-infection, acute infection, and post-infection periods. The main outcomes were Covid-19 hospitalization and all-cause mortality.

RESULTS

Covid-ESKD patients had greater intradialytic and postdialysis systolic BP and lower predialysis weight, postdialysis weight, ultrafiltration rate, and interdialytic weight gain during acute-illness compared to 1-week-before-illness, while these changes were not observed in No-Covid-ESKD patients. After 286 days of follow-up (range, 276-591), there were 18 Covid-19-related hospitalizations and 28 deaths among Covid-ESKD patients. Multivariable logistic regression analysis showed that increases in predialysis systolic BP from 1-week-before-illness to acute-illness (OR, 95%CI = 1.06, 1.02-1.10; p = .004) and Covid-19 vaccination (OR, 95%CI = 0.16, 0.04-0.69; p = .014) were associated with hospitalization in Covid-ESKD patients. Multivariable Cox-regression analysis showed that Covid-19-related hospitalization (HR, 95%CI = 5.17, 2.07-12.96; p < .001) and age (HR, 95%CI = 1.05, 1.01-1.08; p = .008) were independent predictors of all-cause mortality in Covid-ESKD patients.

CONCLUSION

Acute Covid-19 illness is associated with variations in dialysis parameters of volume status in patients with ESKD. Furthermore, increases in predialysis BP during acute Covid-19 illness are associated with an adverse prognosis in Covid-ESKD patients.

Vaccinations, cardiovascular drugs, hospitalization, and mortality in COVID-19 and Long COVID

OBJECTIVE

To identify highest-risk subgroups for COVID-19 and Long COVID(LC), particularly in contexts of influenza and cardiovascular disease(CVD).

METHODS

Using national, linked electronic health records for England (NHS England Secure Data Environment via CVD-COVID-UK/COVID-IMPACT Consortium), we studied individuals (of all ages) with COVID-19 and LC (2020-2023). We compared all-cause hospitalization and mortality by prior CVD, high CV risk, vaccination status (COVID-19/influenza), and CVD drugs, investigating impact of vaccination and CVD prevention using population preventable fractions.

RESULTS

Hospitalization and mortality were 15.3% and 2.0% among 17,373,850 individuals with COVID-19 (LC rate 1.3%), and 16.8% and 1.4% among 301,115 with LC. Adjusted risk of mortality and hospitalization were reduced with COVID-19 vaccination ≥ 2 doses(COVID-19:HR 0.36 and 0.69; LC:0.44 and 0.90). With influenza vaccination, mortality was reduced, but not hospitalization (COVID-19:0.86 and 1.01, and LC:0.72 and 1.05). Mortality and hospitalization were reduced by CVD prevention in those with CVD, e.g., anticoagulants- COVID:19:0.69 and 0.92; LC:0.59 and 0.88; lipid lowering- COVID-19:0.69 and 0.86; LC:0.68 and 0.90. COVID-19 vaccination averted 245044 of 321383 and 7586 of 8738 preventable deaths after COVID-19 and LC, respectively.

INTERPRETATION

Prior CVD and high CV risk are associated with increased hospitalization and mortality in COVID-19 and LC. Targeted COVID-19 vaccination and CVD prevention are priority interventions.

FUNDING

NIHR. HDR UK.

COVID-19 epidemic investigation study of a follow-up cohort of patients with diabetic kidney disease

Introduction

The impact of coronavirus disease 2019 (COVID-19) on diabetic kidney disease (DKD) patients in China is not fully understood. This study aimed to investigate infection status in a DKD cohort post-renal biopsy and analyze vaccination and infection rates, as well as symptom severity, across various renal pathologies in DKD patients.

Methods

This epidemiological survey, centered on COVID-19, employed a Chinese DKD and renal puncture follow-up cohort. A customized questionnaire enabled standardized data gathering. It collected data on clinical characteristics, vaccination and infection statuses, and diverse pathological types. The study analyzed the relationship between vaccination and infection statuses across various pathological types, evaluating characteristics and treatment outcomes in patients with infections.

Results

In total, 437 patients with DKD from 26 Chinese provinces were followed up for a median of 44.6 ± 20 months. COVID-19 infection, vaccination, and novel coronavirus pneumonia (NCP) rates were 73.68%, 59.3%, and 6.63%, respectively. Ten patients with NCP had severe pneumonia or died of COVID-19. Renal pathology revealed that 167 (38.22%) patients had diabetic nephropathy (DN), 171 (39.13%) had non-diabetic renal disease (NDRD), and 99 had DN and NDRD (22.65%). The DN group had the lowest vaccination (54.5%), highest all-cause mortality (3.6%), and highest endpoint rates (34.10%). Compared to patients who were not vaccinated pre-infection (117 cases), vaccinated patients (198 cases) had reduced NCP (6.6% vs. 13.7%), severity (1.0% vs. 3.4%), and endpoint (9.10% vs. 31.60%) rates.

Conclusion

Vaccination can prevent infection and diminish COVID-19 severity in patients with DKD; therefore, increasing vaccination rates is particularly important.

Clinical Trial registration

ClinicalTrails.gov, NCT05888909.

Association between dietary intake of selenium and chronic kidney disease in US adults: a cross-sectional study of NHANES 2015-2018

Background

Chronic kidney disease (CKD) is currently a widespread chronic illness, and its development is influenced by nutrients. Selenium plays a crucial role in the intervention and therapy of various chronic illness. In this study, we aimed to investigate the connection between dietary selenium intake and CKD in adults in the United States.

Methods

We included 6,390 individuals from the datasets of the National Health and Nutrition Examination Survey (NHANES) between 2015 and 2018. We used multiple logistic regression, restricted cubic spline regression, and forest plots to investigate the connection between dietary selenium intake and CKD.

Results

After fully adjusting the data of 6,390 individuals from NHANES between 2015 and 2018, 1,523 (23.83%) of the individuals were identified as having chronic kidney disease (CKD). The rates of CKD in participants with average selenium intakes of ≤0.072, 0.072-0.103, 0.103-0.144, and > 0.144 mg/day were 27.53, 25.11, 22.42, and 19.96%, respectively. After adjusting for potential confounding factors, the fully adjusted odds ratio (OR) values for CKD according to dietary selenium intake were 1 (reference), 0.94 (95% confidence interval (CI): 0.79-1.12, p = 0.466), 0.82 (95% CI:0.68-0.98, p = 0.033), and 0.77 (95% CI:0.63-0.95, p = 0.016) for the four selenium intake levels, respectively, with P trend = 0.007. The dietary selenium intake was negatively associated with the incidence of CKD, after adjusting for other confounding factors. The risk of CKD decreased by 7.7% for every additional 0.1 mg of dietary selenium intake.

Conclusion

A higher dietary selenium intake correlates significantly and negatively with the incidence of CKD.

Active vitamin D analog and SARS-CoV-2 IgG after BNT162b2 vaccination in patients with hemodialysis

INTRODUCTION

Vaccination is the effective strategy for coronavirus disease 2019 (COVID-19). However, few studies have investigated the association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (Ig)G and vitamin D.

METHODS

This study aimed to investigate the association between SARS-CoV-2 IgG and active vitamin D analogs in hemodialysis patients. Blood samples were collected four times: before vaccination and 30, 60, and 90 days after vaccination, BNT162b2 (Pfizer©).

RESULTS

A total of 418 patients were enrolled. The mean age was 71.1 ± 12 years. Almost two thirds of the patients were prescribed active vitamin D analogs. The distribution of SARS-CoV-2 IgG before vaccination was 235 (93-454) AU/mL. After multiple regression analyses, active vitamin D analog use was found to be associated with higher SARS-CoV-2 IgG levels from prevaccination to 90 days postvaccination.

CONCLUSION

This study demonstrated an association between higher SARS-CoV-2 IgG and active vitamin D analog use in hemodialysis patients.

CLINICAL TRIAL REGISTRATION

The study information was registered in the UMIN-CTR (UMIN 000046906).

Serological responses and clinical outcomes following a three-dose primary COVID-19 vaccine schedule in kidney transplant recipients and people on dialysis

Objectives

Despite vaccination strategies, people with chronic kidney disease, particularly kidney transplant recipients (KTRs), remained at high risk of poor COVID-19 outcomes. We assessed serological responses to the three-dose COVID-19 vaccine schedule in KTRs and people on dialysis, as well as seroresponse predictors and the relationship between responses and breakthrough infection.

Methods

Plasma from 30 KTRs and 17 people receiving dialysis was tested for anti-Spike receptor binding domain (RBD) IgG and neutralising antibodies (NAb) to the ancestral and Omicron BA.2 variant after Doses 2 and 3 of vaccination.

Results

After three doses, KTRs achieved lower anti-Spike RBD IgG levels (P < 0.001) and NAb titres than people receiving dialysis (P = 0.002). Seropositive cross-reactive Omicron neutralisation levels were achieved in 11/27 (40.7%) KTRs and 11/14 (78.6%) dialysis recipients. ChAdOx1/viral-vector vaccine type, higher mycophenolate dose (> 1 g per day) and lower absolute B-cell counts predicted poor serological responses in KTRs. ChAdOx-1 vaccine type and higher monocyte counts were negative predictors in dialysis recipients. Among ancestral NAb seroresponders, higher NAb levels positively correlated with higher Omicron neutralisation (R = 0.9, P < 0.001). More KTRs contracted SARS-CoV-2 infection (14/30; 47%) than dialysis recipients (5/17; 29%) and had more severe disease. Those with breakthrough infections had significantly lower median interdose incremental change in anti-Spike RBD IgG and ancestral NAb titres.

Conclusion

Serological responses to COVID-19 vaccines in KTRs lag behind their dialysis counterparts. KTRs remained at high risk of breakthrough infection after their primary vaccination schedule underlining their need for booster doses, strict infection prevention measures and close surveillance.

Hemodialysis Procedures for Stable Incident and Prevalent Patients Optimize Hemodynamic Stability, Dialysis Dose, Electrolytes, and Fluid Balance

The demographic profile of patients transitioning from chronic kidney disease to kidney replacement therapy is changing, with a higher prevalence of aging patients with multiple comorbidities such as diabetes mellitus and heart failure. Cardiovascular disease remains the leading cause of mortality in this population, exacerbated by the cardiovascular stress imposed by the HD procedure. The first year after transitioning to hemodialysis is associated with increased risks of hospitalization and mortality, particularly within the first 90-120 days, with greater vulnerability observed among the elderly. Based on data from clinics in Fresenius Medical Care Europe, Middle East, and Africa NephroCare, this review aims to optimize hemodialysis procedures to reduce mortality risk in stable incident and prevalent patients. It addresses critical aspects such as treatment duration, frequency, choice of dialysis membrane, dialysate composition, blood and dialysate flow rates, electrolyte composition, temperature control, target weight management, dialysis adequacy, and additional protocols, with a focus on mitigating prevalent intradialytic complications, particularly intradialytic hypotension prevention.

Klotho-derived peptide KP1 ameliorates SARS-CoV-2-associated acute kidney injury

Introduction: The severe cases of COVID-19, a disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), often present with acute kidney injury (AKI). Although old age and preexisting medical conditions have been identified as principal risk factors for COVID-19-associated AKI, the molecular basis behind such a connection remains unknown. In this study, we investigated the pathogenic role of Klotho deficiency in COVID-19-associated AKI and explored the therapeutic potential of Klotho-derived peptide 1 (KP1). Methods: We assessed the susceptibility of Klotho deficient Kl/Kl mice to developing AKI after expression of SARS-CoV-2 N protein. The role of KP1 in ameliorating tubular injury was investigated by using cultured proximal tubular cells (HK-2) in vitro and mouse model of ischemia-reperfusion injury (IRI) in vivo. Results: Renal Klotho expression was markedly downregulated in various chronic kidney disease (CKD) models and in aged mice. Compared to wild-type counterparts, mutant KL/KL mice were susceptible to overexpression of SARS-CoV-2 N protein and developed kidney lesions resembling AKI. In vitro, expression of N protein alone induced HK-2 cells to express markers of tubular injury, cellular senescence, apoptosis and epithelial-mesenchymal transition, whereas both KP1 and Klotho abolished these lesions. Furthermore, KP1 mitigated kidney dysfunction, alleviated tubular injury and inhibited apoptosis in AKI model induced by IRI and N protein. Conclusion: These findings suggest that Klotho deficiency is a key determinant of developing COVID-19-associated AKI. As such, KP1, a small peptide recapitulating Klotho function, could be an effective therapeutic for alleviating AKI in COVID-19 patients.

Nationwide in-hospital mortality and morbidity analysis of COVID-19 in advanced chronic kidney disease, dialysis and kidney transplant recipients

Background

Patients with advanced chronic kidney disease (CKD), end-stage kidney disease (ESKD), and kidney transplants (KT) are at an elevated risk for COVID-19 infection, hospitalization, and mortality. A comprehensive comparison of morbidity and mortality between these populations with kidney disease and individuals without any kidney disease is lacking.

Methods

We analysed the 2020 Nationwide Inpatient Sample (NIS) database for non-elective adult COVID-19 hospitalizations, categorizing patients into advanced CKD, ESKD, KT, and kidney disease-free cohorts. Our analysis included a description of the distribution of comorbidities across the entire spectrum of CKD, ESKD, and KT. Additionally, we investigated in-hospital mortality, morbidity, and resource utilization, adjusting for potential confounders through multivariable regression models.

Results

The study included 1,018,915 adults hospitalized for COVID-19 in 2020. The incidence of advanced CKD, ESKD, and KT in this cohort was 5.8%, 3.8%, and 0.4%, respectively. Patients with advanced CKD, ESKD, and KT exhibited higher multimorbidity burdens, with 90.3%, 91.0%, and 75.2% of patients in each group having a Charlson comorbidity index (CCI) equal to or greater than 3. The all-cause in-hospital mortality ranged from 9.3% in kidney disease-free patients to 20.6% in advanced CKD, 19.4% in ESKD, and 12.4% in KT patients. After adjusting for potential confounders at both the patient and hospital levels, CKD stages 3-5; ESKD; and KT were found to be associated with increased odds of mortality, with adjusted odds ratios (aOR) of 1.34, 1.80, 2.66, 1.97, and 1.69, respectively.

Conclusion

Patients hospitalized for COVID-19 with advanced CKD, ESKD, or KT demonstrated a higher burden of comorbidities and increased mortality rates compared to those without kidney disease. After adjusting for confounders, CKD stages 3-5; ESKD; and KT were identified as independent risk factors for in-hospital mortality, illustrating a dose-response relationship between the odds of mortality and adverse outcomes as CKD progressed from stages 3 to 5. Our study highlights the necessity for enhanced management of comorbidities, targeted interventions, and vigorous vaccination efforts to mitigate the risk of adverse outcomes in the vulnerable populations of patients with CKD, ESKD, and KT.

COVID and the Kidney: An Update

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has led to a global pandemic that continues to be responsible for ongoing health issues for people worldwide. Immunocompromised individuals such as kidney transplant recipients and dialysis patients have been and continue to be among the most affected, with poorer outcomes after infection, impaired response to COVID-19 vaccines, and protracted infection. The pandemic also has had a significant impact on patients with underlying chronic kidney disease (CKD), with CKD increasing susceptibility to COVID-19, risk of hospital admission, and mortality. COVID-19 also has been shown to lead to acute kidney injury (AKI) through both direct and indirect mechanisms. The incidence of COVID-19 AKI has been decreasing as the pandemic has evolved, but continues to be associated with adverse patient outcomes correlating with the severity of AKI. There is also increasing evidence examining the longer-term effect of COVID-19 on the kidney demonstrating continued decline in kidney function several months after infection. This review summarizes the current evidence examining the impact of COVID-19 on the kidney, covering both the impact on patients with CKD, including patients receiving kidney replacement therapy, in addition to discussing COVID-19 AKI.

Accelerated waning of the humoral response to COVID-19 vaccines in obesity

Obesity is associated with an increased risk of severe Coronavirus Disease 2019 (COVID-19) infection and mortality. COVID-19 vaccines reduce the risk of serious COVID-19 outcomes; however, their effectiveness in people with obesity is incompletely understood. We studied the relationship among body mass index (BMI), hospitalization and mortality due to COVID-19 among 3.6 million people in Scotland using the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) surveillance platform. We found that vaccinated individuals with severe obesity (BMI > 40 kg/m2) were 76% more likely to experience hospitalization or death from COVID-19 (adjusted rate ratio of 1.76 (95% confidence interval (CI), 1.60-1.94). We also conducted a prospective longitudinal study of a cohort of 28 individuals with severe obesity compared to 41 control individuals with normal BMI (BMI 18.5-24.9 kg/m2). We found that 55% of individuals with severe obesity had unquantifiable titers of neutralizing antibody against authentic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus compared to 12% of individuals with normal BMI (P = 0.0003) 6 months after their second vaccine dose. Furthermore, we observed that, for individuals with severe obesity, at any given anti-spike and anti-receptor-binding domain (RBD) antibody level, neutralizing capacity was lower than that of individuals with a normal BMI. Neutralizing capacity was restored by a third dose of vaccine but again declined more rapidly in people with severe obesity. We demonstrate that waning of COVID-19 vaccine-induced humoral immunity is accelerated in individuals with severe obesity. As obesity is associated with increased hospitalization and mortality from breakthrough infections, our findings have implications for vaccine prioritization policies.

Clinical Outcomes and Vaccine Effectiveness for SARS-CoV-2 Infection in People Attending Advanced CKD Clinics: A Retrospective Provincial Cohort Study

BACKGROUND

People with advanced CKD are at high risk of mortality and morbidity from coronavirus disease 2019 (COVID-19). We measured rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe outcomes in a large population attending advanced CKD clinics during the first 21 months of the pandemic. We examined risk factors for infection and case fatality, and we assessed vaccine effectiveness in this population.

METHODS

In this retrospective cohort study, we analyzed data on demographics, diagnosed SARS-CoV-2 infection rates, outcomes, and associated risk factors, including vaccine effectiveness, for people attending a province-wide network of advanced CKD clinics during the first four waves of the pandemic in Ontario, Canada.

RESULTS

In a population of 20,235 patients with advanced CKD, 607 were diagnosed with SARS-CoV-2 infection over 21 months. The case fatality rate at 30 days was 19% overall but declined from 29% in the first wave to 14% in the fourth. Hospitalization and intensive care unit (ICU) admission rates were 41% and 12%, respectively, and 4% started long-term dialysis within 90 days. Significant risk factors for diagnosed infection on multivariable analysis included lower eGFR, higher Charlson Comorbidity Index, attending advanced CKD clinics for more than 2 years, non-White ethnicity, lower income, living in the Greater Toronto Area, and long-term care home residency. Being doubly vaccinated was associated with lower 30-day case fatality rate (odds ratio [OR], 0.11; 95% confidence interval [CI], 0.03 to 0.52). Older age (OR, 1.06 per year; 95% CI, 1.04 to 1.08) and higher Charlson Comorbidity Index (OR, 1.11 per unit; 95% CI, 1.01 to 1.23) were associated with higher 30-day case fatality rate.

CONCLUSIONS

People attending advanced CKD clinics and diagnosed with SARS-CoV-2 infection in the first 21 months of the pandemic had high case fatality and hospitalization rates. Fatality rates were significantly lower in those who were doubly vaccinated.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_04_10_CJN10560922.mp3.

Kidney health for all: preparedness for the unexpected in supporting the vulnerable

As the rate of natural disasters and other devastating events caused by human activities increases, the burden on the health and well-being of those affected by kidney disease has been immeasurable. Health system preparedness, which involves creating a resilient system that is able to deal with the health needs of the entire community during times of unexpected disruptions to usual care, has become globally important. In the wake of the COVID-19 pandemic, there is a heightened awareness of the amplification of negative effects on the renal community. Paradoxically, the complex medical needs of those who have kidney diseases are not met by systems handling crises, often compounded by an acute increase in burden via new patients as a result of the crisis itself. Disruptions in kidney care as a result of unexpected events are becoming more prevalent and likely to increase in the years to come. It is therefore only appropriate that the theme for this year's World Kidney Day will focus on Kidney Health for All: preparedness for the unexpected in supporting the vulnerable.

Identifying subtypes of chronic kidney disease with machine learning: development, internal validation and prognostic validation using linked electronic health records in 350,067 individuals

BACKGROUND

Although chronic kidney disease (CKD) is associated with high multimorbidity, polypharmacy, morbidity and mortality, existing classification systems (mild to severe, usually based on estimated glomerular filtration rate, proteinuria or urine albumin-creatinine ratio) and risk prediction models largely ignore the complexity of CKD, its risk factors and its outcomes. Improved subtype definition could improve prediction of outcomes and inform effective interventions.

METHODS

We analysed individuals ≥18 years with incident and prevalent CKD (n = 350,067 and 195,422 respectively) from a population-based electronic health record resource (2006-2020; Clinical Practice Research Datalink, CPRD). We included factors (n = 264 with 2670 derived variables), e.g. demography, history, examination, blood laboratory values and medications. Using a published framework, we identified subtypes through seven unsupervised machine learning (ML) methods (K-means, Diana, HC, Fanny, PAM, Clara, Model-based) with 66 (of 2670) variables in each dataset. We evaluated subtypes for: (i) internal validity (within dataset, across methods); (ii) prognostic validity (predictive accuracy for 5-year all-cause mortality and admissions); and (iii) medications (new and existing by British National Formulary chapter).

FINDINGS

After identifying five clusters across seven approaches, we labelled CKD subtypes: 1. Early-onset, 2. Late-onset, 3. Cancer, 4. Metabolic, and 5. Cardiometabolic. Internal validity: We trained a high performing model (using XGBoost) that could predict disease subtypes with 95% accuracy for incident and prevalent CKD (Sensitivity: 0.81-0.98, F1 score:0.84-0.97). Prognostic validity: 5-year all-cause mortality, hospital admissions, and incidence of new chronic diseases differed across CKD subtypes. The 5-year risk of mortality and admissions in the overall incident CKD population were highest in cardiometabolic subtype: 43.3% (42.3-42.8%) and 29.5% (29.1-30.0%), respectively, and lowest in the early-onset subtype: 5.7% (5.5-5.9%) and 18.7% (18.4-19.1%).

MEDICATIONS

Across CKD subtypes, the distribution of prescription medication classes at baseline varied, with highest medication burden in cardiometabolic and metabolic subtypes, and higher burden in prevalent than incident CKD.

INTERPRETATION

In the largest CKD study using ML, to-date, we identified five distinct subtypes in individuals with incident and prevalent CKD. These subtypes have relevance to study of aetiology, therapeutics and risk prediction.

FUNDING

AstraZeneca UK Ltd, Health Data Research UK.

Impact of the COVID-19 pandemic on the kidney community: lessons learned and future directions

The coronavirus disease 2019 (COVID-19) pandemic has disproportionately affected patients with kidney disease, causing significant challenges in disease management, kidney research and trainee education. For patients, increased infection risk and disease severity, often complicated by acute kidney injury, have contributed to high mortality. Clinicians were faced with high clinical demands, resource shortages and novel ethical dilemmas in providing patient care. In this review, we address the impact of COVID-19 on the entire spectrum of kidney care, including acute kidney injury, chronic kidney disease, dialysis and transplantation, trainee education, disparities in health care, changes in health care policies, moral distress and the patient perspective. Based on current evidence, we provide a framework for the management and support of patients with kidney disease, infection mitigation strategies, resource allocation and support systems for the nephrology workforce.

Effects of Selenium on Chronic Kidney Disease: A Mendelian Randomization Study

BACKGROUND

Previous observational studies have shown that there is a controversial association between selenium levels and chronic kidney disease (CKD). Our aim was to assess the causal relationship between selenium levels and CKD using Mendelian randomization (MR) analysis.

METHODS

We used the two-sample Mendelian randomization (MR) method to analyze the causal role of selenium levels on CKD risk. The variants associated with selenium levels were extracted from a large genome-wide association study (GWAS) meta-analysis of circulating selenium levels (n = 5477) and toenail selenium levels (n = 4162) in the European population. Outcome data were from the largest GWAS meta-analysis of European-ancestry participants for kidney function to date. Inverse variance weighted (IVW) method was used as the main analysis and a series of sensitivity analyses were carried out to detect potential violations of MR assumptions.

RESULTS

The MR analysis results indicate that the genetically predicted selenium levels were associated with decreased estimated glomerular filtration (eGFR) (effect = -0.0042, 95% confidence interval [CI]: -0.0053-0.0031, p = 2.186 × 10^-13) and increased blood urea nitrogen (BUN) (effect = 0.0029, 95% confidence interval [CI]: 0.0006-0.0052, p = 0.0136) with no pleiotropy detected.

CONCLUSIONS

The MR study indicated that an increased level of selenium is a causative factor for kidney function impairment.

A novel gene signature based on the hub genes of COVID-19 predicts the prognosis of idiopathic pulmonary fibrosis

Background: Increasing evidence has demonstrated that there was a strong correlation between COVID-19 and idiopathic pulmonary fibrosis (IPF). However, the studies are limited, and the real biological mechanisms behind the IPF progression were still uncleared.

Methods: GSE70866 and GSE 157103 datasets were downloaded. The weight gene co-expression network analysis (WGCNA) algorithms were conducted to identify the most correlated gene module with COVID-19. Then the genes were extracted to construct a risk signature in IPF patients by performing Univariate and Lasso Cox Regression analysis. Univariate and Multivariate Cox Regression analyses were used to identify the independent value for predicting the prognosis of IPF patients. What’s more, the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and gene set enrichment analysis (GSEA) were conducted to unveil the potential biological pathways. CIBERSORT algorithms were performed to calculate the correlation between the risk score and immune cells infiltrating levels.

Results: Two hundred thirty three differentially expressed genes were calculated as the hub genes in COVID-19. Fourteen of these genes were identified as the prognostic differentially expressed genes in IPF. Three (MET, UCHL1, and IGF1) of the fourteen genes were chosen to construct the risk signature. The risk signature can greatly predict the prognosis of high-risk and low-risk groups based on the calculated risk score. The functional pathway enrichment analysis and immune infiltrating analysis showed that the risk signature may regulate the immune-related pathways and immune cells.

Conclusion: We identified prognostic differentially expressed hub genes related to COVID-19 in IPF. A risk signature was constructed based on those genes and showed great value for predicting the prognosis in IPF patients. What’s more, three genes in the risk signature may be clinically valuable as potential targets for treating IPF patients and IPF patients with COVID-19.