Strong protective effect of the APOL1 p.N264K variant against G2-associated focal segmental glomerulosclerosis and kidney disease

African Americans have a significantly higher risk of developing chronic kidney disease, especially focal segmental glomerulosclerosis -, than European Americans. Two coding variants (G1 and G2) in the APOL1 gene play a major role in this disparity. While 13% of African Americans carry the high-risk recessive genotypes, only a fraction of these individuals develops FSGS or kidney failure, indicating the involvement of additional disease modifiers. Here, we show that the presence of the APOL1 p.N264K missense variant, when co-inherited with the G2 APOL1 risk allele, substantially reduces the penetrance of the G1G2 and G2G2 high-risk genotypes by rendering these genotypes low-risk. These results align with prior functional evidence showing that the p.N264K variant reduces the toxicity of the APOL1 high-risk alleles. These findings have important implications for our understanding of the mechanisms of APOL1-associated nephropathy, as well as for the clinical management of individuals with high-risk genotypes that include the G2 allele.

Strong protective effect of the APOL1 p.N264K variant against G2-associated focal segmental glomerulosclerosis and kidney disease

Black Americans have a significantly higher risk of developing chronic kidney disease (CKD), especially focal segmental glomerulosclerosis (FSGS), than European Americans. Two coding variants (G1 and G2) in the APOL1 gene play a major role in this disparity. While 13% of Black Americans carry the high-risk recessive genotypes, only a fraction of these individuals develops FSGS or kidney failure, indicating the involvement of additional disease modifiers. Here, we show that the presence of the APOL1 p.N264K missense variant, when co-inherited with the G2 APOL1 risk allele, substantially reduces the penetrance of the G1G2 and G2G2 high-risk genotypes by rendering these genotypes low-risk. These results align with prior functional evidence showing that the p.N264K variant reduces the toxicity of the APOL1 high-risk alleles. These findings have important implications for our understanding of the mechanisms of APOL1 -associated nephropathy, as well as for the clinical management of individuals with high-risk genotypes that include the G2 allele.

Genome-wide association analyses define pathogenic signaling pathways and prioritize drug targets for IgA nephropathy

IgA nephropathy (IgAN) is a progressive form of kidney disease defined by glomerular deposition of IgA. Here we performed a genome-wide association study of 10,146 kidney-biopsy-diagnosed IgAN cases and 28,751 controls across 17 international cohorts. We defined 30 genome-wide significant risk loci explaining 11% of disease risk. A total of 16 loci were new, including TNFSF4/TNFSF18, REL, CD28, PF4V1, LY86, LYN, ANXA3, TNFSF8/TNFSF15, REEP3, ZMIZ1, OVOL1/RELA, ETS1, IGH, IRF8, TNFRSF13B and FCAR. The risk loci were enriched in gene orthologs causing abnormal IgA levels when genetically manipulated in mice. We also observed a positive genetic correlation between IgAN and serum IgA levels. High polygenic score for IgAN was associated with earlier onset of kidney failure. In a comprehensive functional annotation analysis of candidate causal genes, we observed convergence of biological candidates on a common set of inflammatory signaling pathways and cytokine ligand-receptor pairs, prioritizing potential new drug targets.

Multi-population genome-wide association study implicates immune and non-immune factors in pediatric steroid-sensitive nephrotic syndrome

Pediatric steroid-sensitive nephrotic syndrome (pSSNS) is the most common childhood glomerular disease. Previous genome-wide association studies (GWAS) identified a risk locus in the HLA Class II region and three additional independent risk loci. But the genetic architecture of pSSNS, and its genetically driven pathobiology, is largely unknown. Here, we conduct a multi-population GWAS meta-analysis in 38,463 participants (2440 cases). We then conduct conditional analyses and population specific GWAS. We discover twelve significant associations-eight from the multi-population meta-analysis (four novel), two from the multi-population conditional analysis (one novel), and two additional novel loci from the European meta-analysis. Fine-mapping implicates specific amino acid haplotypes in HLA-DQA1 and HLA-DQB1 driving the HLA Class II risk locus. Non-HLA loci colocalize with eQTLs of monocytes and numerous T-cell subsets in independent datasets. Colocalization with kidney eQTLs is lacking but overlap with kidney cell open chromatin suggests an uncharacterized disease mechanism in kidney cells. A polygenic risk score (PRS) associates with earlier disease onset. Altogether, these discoveries expand our knowledge of pSSNS genetic architecture across populations and provide cell-specific insights into its molecular drivers. Evaluating these associations in additional cohorts will refine our understanding of population specificity, heterogeneity, and clinical and molecular associations.

Risk of bleeding after percutaneous native kidney biopsy in patients receiving low-dose aspirin: a single-center retrospective study

BACKGROUND

Although discontinuation of antiplatelet agents at least 5 days before kidney biopsy is commonly recommended, the evidence behind this practice is of low level. Indeed, few non-randomized studies previously showed an equivalent risk of bleeding in patients receiving aspirin therapy.

METHODS

We conducted a single center retrospective study comparing the risk of complications after percutaneous native kidney biopsy in patients who received low-dose aspirin (ASA) within 5 days from biopsy and those who did not. The main outcome was the difference in the incidence of major complications (red blood cell transfusion, need for selective arterial embolization, surgery, nephrectomy). Secondary outcomes included difference in minor complications, comparison between patients who received ASA within 48 h or within 3-5 days, identification of independent factors predictive of major complications.

RESULTS

We analyzed data on 750 patients, of whom 94 received ASA within 5 days from biopsy. There were no significant differences in the proportion of major complications in patients receiving or not receiving ASA (2.59% and 3.19%, respectively, percentage point difference 1%, 95% CI - 3 to 4%, p = 0.74). Groups were also comparable for minor complications; among patients receiving ASA, there were no differences in major bleeding between those who received ASA within 48 h or 3-5 days from biopsy. Significant baseline predictors of major bleeding in our cohort were platelet count lower than 120*10³/microliter, higher diastolic blood pressure and higher blood urea.

CONCLUSIONS

Treatment with low-dose ASA within 5 days from kidney biopsy did not increase the risk of complications after the procedure.

PAX2/Renal Coloboma Syndrome Expresses Extreme Intrafamilial Phenotypic Variability

Renal coloboma syndrome (RCS) is a disease characterized by kidney and ocular anomalies (kidney hypodysplasia and coloboma). RCS is caused, in half of the cases, by mutations in the paired box 2 (PAX2) gene, a critical organogenesis transcriptional factor. We report the case of a newborn with kidney hypodysplasia in a negative parental context where mother and father were phenotypically unaffected at the initial evaluation. The maternal family presented an important history of kidney disease with undefined diagnosis. Molecular characterization identified a PAX2 variant, classified as likely pathogenic. This variant segregates with the disease, and it was also found in the newborn, explaining his severe symptoms. It is noteworthy that the mother shows the same PAX2 variant, with an apparently negative kidney phenotype, displaying the possibility of an extreme variable expressivity of the disease. This feature suggests extreme caution in segregation analysis and family counseling of PAX2 pedigrees.

Prevalence, clinical course and outcomes of COVID-19 in peritoneal dialysis (PD) patients: a single-center experience

INTRODUCTION

There are limited data on the effects of COVID-19 on peritoneal dialysis (PD) patients. This study aimed to describe the impact of COVID-19 on the PD population.

METHODS

A monocentric retrospective observational study was conducted on 146 consecutive PD patients followed from January 2020 to March 2022 at the University Hospital of Modena, Italy.

RESULTS

Twenty-seven (18.4%) PD patients experienced 29 episodes of SARS-CoV-2 infection, corresponding to an incidence rate of 0.16 episodes/patient-year. Median age of COVID-19 patients was 60.4 (interquartile range [IQR] 50.2-66.5) years. In unvaccinated patients (n. 9), COVID-19 was always symptomatic and manifested with fever (100%) and cough (77.7%). COVID-19 caused hospital admission of three (33.3%) patients and two (22.2%) died of septic shock. COVID-19 was symptomatic in 83.3% of vaccinated subjects (n.18) and manifested with fever (61.1%) and cough (55.6%). Hospital admission occurred in 27.8% of the subjects but all were discharged home. Median SARS-CoV-2 shedding was 32 and 26 days in the unvaccinated and vaccinated groups, respectively. At the end of the follow-up, COVID-19 triggered the shift from PD to HD in two subjects without affecting the residual renal function of the remaining patients. Overall, COVID-19 caused an excess death of 22.2%. COVID-19 vaccination refusal accounted for only 1.6% in this cohort of patients.

CONCLUSION

COVID-19 incident rate was 0.16 episodes/patient-year in the PD population. About one-third of the patients were hospitalized for severe infection. Fatal outcome occurred in two (7.4%) unvaccinated patients. A low vaccination refusal rate was observed in this population.

Artificial intelligence in glomerular diseases

In this narrative review, we focus on the application of artificial intelligence in the clinical history of patients with glomerular disease, digital pathology in kidney biopsy, renal ultrasonography imaging, and prediction of chronic kidney disease (CKD). With the development of natural language processing, the clinical history of a patient can be used to identify a computable phenotype. In kidney pathology, digital imaging has adopted innovative deep learning algorithms (DLAs) that can improve the predictive capability of the examined lesions. However, at this time, these applications can only be used in research because there is no recognized validation to replace the conventional diagnostic applications. Kidney ultrasonography, used in the clinical examination of patients, provides information about the progression of kidney damage. Machine learning algorithms (MLAs) with promising results for the early detection of CKD have been proposed, but, still, they are not solid enough to be incorporated into the clinical practice. A few tools for glomerulonephritis, based on MLAs, are available in clinical practice. They can be downloaded on computers and cellular phones but can only be applied to uniracial cohorts of patients. To improve their performance, it is necessary to organize large consortia with multiracial cohorts. Finally, in many studies MLA development has been carried out using retrospective cohorts. The performance of the models might differ in retrospective cohorts compared to real-world data. Therefore, the models should be validated in prospective external large cohorts.

Skin reaction with Eosinophilia and Systemic Symptoms after lenalidomide in peritoneal Dialysis

The Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a fatal and immune-mediated idiosyncratic drug reaction, with symptoms of fever, skin eruptions (that involves more than half of the body surface), facial oedema and hematological disorders, all presenting within the latent period following drug intake. Effects can also be seen on multiple organs, most notably hepatitis in liver and acute interstitial nephritis in kidney, generally post-administration of allopurinol. The European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) classifies the DRESS Syndrome cases as "definite", "probable" or "possible", based on clinical and laboratory features. Different pathogenetic mechanisms have been involved in this disease, including immunological reactions and HHV-6 reactivation. In our experience, a 72-year-old male, affected by myeloma in peritoneal dialysis, developed a rare case of DRESS syndrome after lenalidomide administration (less than ten cases are known) with HHV-6 reactivation. According to literature, we withdrew the drug and gave methylprednisolone 0,8 mg/kg orally and IVIG 1 gr/kg for two days. Despite this therapy, DRESS syndrome relapsed during steroid taper with rash, thrombocytopenia, hepatitis and high troponin level. A single cycle of intravenous immunoglobulin 0,5 g/kg for four days was enough for syndrome remission. Only few cases are reported in literature, but because of the increasing use of lenalidomide and the autoimmune sequelae of DRESS syndrome, a broad workup and a multidisciplinar careful approach could help in diagnosis, treatment and follow-up.

Rethinking Chronic Kidney Disease in the Aging Population

The process of aging population will inevitably increase age-related comorbidities including chronic kidney disease (CKD). In light of this demographic transition, the lack of an age-adjusted CKD classification may enormously increase the number of new diagnoses of CKD in old subjects with an indolent decline in kidney function. Overdiagnosis of CKD will inevitably lead to important clinical consequences and pronounced negative effects on the health-related quality of life of these patients. Based on these data, an appropriate workup for the diagnosis of CKD is critical in reducing the burden of CKD worldwide. Optimal management of CKD should be based on prevention and reduction of risk factors associated with kidney injury. Once the diagnosis of CKD has been made, an appropriate staging of kidney disease and timely prescriptions of promising nephroprotective drugs (e.g., RAAS, SGLT-2 inhibitors, finerenone) appear crucial to slow down the progression toward end-stage kidney disease (ESKD). The management of elderly, comorbid and frail patients also opens new questions on the appropriate renal replacement therapy for this subset of the population. The non-dialytic management of CKD in old subjects with short life expectancy features as a valid option in patient-centered care programs. Considering the multiple implications of CKD for global public health, this review examines the prevalence, diagnosis and principles of treatment of kidney disease in the aging population.

Automated Prediction of Kidney Failure in IgA Nephropathy with Deep Learning from Biopsy Images

BACKGROUND AND OBJECTIVES

Digital pathology and artificial intelligence offer new opportunities for automatic histologic scoring. We applied a deep learning approach to IgA nephropathy biopsy images to develop an automatic histologic prognostic score, assessed against ground truth (kidney failure) among patients with IgA nephropathy who were treated over 39 years. We assessed noninferiority in comparison with the histologic component of currently validated predictive tools. We correlated additional histologic features with our deep learning predictive score to identify potential additional predictive features.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Training for deep learning was performed with randomly selected, digitalized, cortical Periodic acid-Schiff-stained sections images (363 kidney biopsy specimens) to develop our deep learning predictive score. We estimated noninferiority using the area under the receiver operating characteristic curve (AUC) in a randomly selected group (95 biopsy specimens) against the gold standard Oxford classification (MEST-C) scores used by the International IgA Nephropathy Prediction Tool and the clinical decision supporting system for estimating the risk of kidney failure in IgA nephropathy. We assessed additional potential predictive histologic features against a subset (20 kidney biopsy specimens) with the strongest and weakest deep learning predictive scores.

RESULTS

We enrolled 442 patients; the 10-year kidney survival was 78%, and the study median follow-up was 6.7 years. Manual MEST-C showed no prognostic relationship for the endocapillary parameter only. The deep learning predictive score was not inferior to MEST-C applied using the International IgA Nephropathy Prediction Tool and the clinical decision supporting system (AUC of 0.84 versus 0.77 and 0.74, respectively) and confirmed a good correlation with the tubolointerstitial score (r=0.41, P<0.01). We observed no correlations between the deep learning prognostic score and the mesangial, endocapillary, segmental sclerosis, and crescent parameters. Additional potential predictive histopathologic features incorporated by the deep learning predictive score included (1) inflammation within areas of interstitial fibrosis and tubular atrophy and (2) hyaline casts.

CONCLUSIONS

The deep learning approach was noninferior to manual histopathologic reporting and considered prognostic features not currently included in MEST-C assessment.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_07_26_CJN01760222.mp3.

MO180: Reactogenicity of MRNA-1273 Vaccine in Patients on Haemodialysis

BACKGROUND AND AIMS

mRNA-1273 vaccine (previously known as vaccine Moderna) has shown 94.1% efficacy at preventing COVID-19 illness in the general population. Vaccine-related adverse events (AEs) were usually mild or moderate in intensity and resolved within a few days. Nevertheless, the fear of developing AEs led some patients on haemodialysis to deny vaccination or additional booster doses. No studies have been conducted to evaluate the reactogenicity of the mRNA-1273 vaccine in dialysis patients. To inform public health and clinical practice, we investigated the safety of the mRNA-1273 vaccine in a cohort of patients on haemodialysis.

METHOD

We conducted a retrospective analysis of in-centre haemodialysis patients without a prior COVID-19 diagnosis who underwent mRNA-1273 vaccine from 1 March to 30 April 2021. mRNA-1273 vaccine was performed in all patients without signs of ongoing infection or COVID-19 who provided written consent from 24 March to 30 April 2021.

AEs occurring after the first and the second doses were collected and classified as local or systemic.

RESULTS

Overall, 126 patients on chronic maintenance dialysis were vaccinated with two doses of mRNA-1273 vaccine. Mean age was 68 (IQR, 54.7–76) years and 53.6% of patients were aged ≥65 years (Table 1). AEs occurred in 57.9% and 61.9% of patients after the first dose and second dose, respectively. The most common AEs were injection-site pain (61.9%), erythema (4.8%), itching (4.8%), swelling (16.7%), axillary swelling/tenderness (2.4%), fever (17.5%) headache (7.9%), fatigue (23.8%), myalgia (17.5%), arthralgia (12.7%), dyspnoea (2.4%), nausea/vomiting (7.1%), diarrhoea (5.6%), shivers (4%) and vertigo (1.6%).

The rates of local AEs were similar after the first and second doses (P = .8), whereas systemic AEs occurred more frequently after the second dose (P = .001). Fever (P = .03), fatigue (P = .02) and nausea/vomiting (P = .03) were significantly more frequent after the second dose of the vaccine (Figure 1). Analysis of the data detected statistically significant differences in duration of axillary swelling/tenderness (P = .07) and diarrhoea (P = .02) between the first and second. In both cases, these symptoms lasted longer after the second dose of the vaccine. There were no age-related differences in the rate of AEs between older (≥65 years) and younger participants (18–64 years). Lastly, we noted a lower rate of AEs in hemodialysis patients after the first dose (57.9% versus 84.2%) and second doses (61.9% versus 88.6%) compared to the general population.

CONCLUSION

RNA-1273 vaccine was associated with the development of transient AEs after the first (57.9%) and second doses (61.9%) in patients on haemodialysis. Systemic AEs were more common after the second dose than the first dose of vaccine. The duration of AEs lasted for a few days, without any apparent consequences. These data confirm the safety of the RNA-1273 vaccine in haemodialysis patients and support the promotion of COVID-19 vaccination in hesitant patients.

MO137: Sarcoidosis in a Living Kidney Donor Candidate: Case Report and Review of the Literature

BACKGROUND AND AIMS

Sarcoidosis (SCD) is a granulomatous disease that mostly affects young adults, presenting with hilar adenopathy, lung reticular opacities and skin/joint/eye lesions. Incidence varies in Europe between 0.3% and 1.5%, higher in southern countries. Up to one-third of patients have extrathoracic manifestations.

 Renal involvement varies among different case series. Despite a prevalence of about 13% in autopsies on systemic SCD affected individuals, it is clinically evident in 0.7–4.3% of patients, with a reduced glomerular filtration rate associated with mild or absent urinary anomalies. It usually presents as a tubulointerstitial nephritis at kidney biopsy. Noncaseating granulomas are typical but not always present. Renal injury can also derive from hyperkalcaemia and hypercalciuria (secondary to vitaminD production in granulomas), which cause nephrocalcinosis or nephrolitiasis. A clinical presentation with hyperkalcaemia associates to a better response to therapy (prednisone 1 mg/kg/day for 6–12 weeks, tapered in 6–9 months). An Italian survey on SCD acute kidney injury (AKI) described female sex, hyperkalaemia and absence of granulomas at biopsy as positive prognostic factors, without any correlation between proteinuria and histological damage. SCD AKI evolved to CKD in over 60% of cases (37.5% without comorbidities at onset), with a mean GFR slope of 5 mL/min/year when granulomatous interstitial nephritis was present.

METHOD

We describe the case of a 55-year-old male, who proposed as a living kidney donor for his wife. His clinical history included a paranoid episode 20 years before, compensated and on psychiatric follow-up at the moment of the screening, dyslipidaemia and normal blood pressure.

RESULTS

Preoperative screening showed a renal function just above safety threshold for donation (cystatin C-creatinine CKD-EPI 80 mL/min/1.73 m2), a normal urinary sediment and no proteinuria. A thoracic and abdominal CT scan (Figure 1) described numerous aorto-caval adenopathies, stable at a second CT after 3 months. Lungs were unaffected, kidneys and the urinary tract were regular, without calcifications or stones.

 No infection was detected (negative QuantiFERON, HIV, EBV &lt;1000 copies/mL), suggesting a differential diagnosis between lymphoma and SCD. Serum and urine electrophoresis, immunofixation, light chains, Bence Jones and peripheral blood lymphocyte typing were checked in parallel to ACE dosing; 24-h urine calcium, calcemia, vitamin D, dermatological and ocular examination all normal. An endobronchial ultrasound biopsy was performed, after a PET (Figure 2) to identify the targets with the highest SUV (3.9–6.7). Histology described normal lymphocytes, noncaseating granulomas with sarcoidosis epithelioid histiocytes.

CONCLUSION

Stage 1 pulmonary SCD without clinical renal involvement was confirmed. Although in a single case of living kidney donation from SCD affected subject was reported, data on GFR deterioration in the long term are lacking. Considering the baseline renal function of the potential donor and the not-quantifiable risk of future AKI, we decided to deem him unfit for donation, despite the absence of markers of disease activity at the moment of the screening. Kidney biopsy will be considered in the future in case of urinary abnormalities or GFR deterioration.

MO672: Covid-19 in Patients on Peritoneal Dialysis: A Case-Series

BACKGROUND AND AIMS

A great amount of information has been divulged on the epidemiology and outcome of coronavirus disease 2019 (COVID-19) in patients with ESRD. The majority of the studies have been conducted in patients on maintenance hemodialysis (HD) and kidney transplant recipients. Unfortunately, few studies focused on the outcome of peritoneal dialysis (PD) patients. Information regarding this subset of the population has been extrapolated from aggregated data including a higher percentage of HD patients. As a result, the impact of COVID-19 is indefinite in patients receiving PD. We conducted a study to better understand how patients on PD have been affected by COVID-19.

METHOD

We conducted a single-center retrospective analysis of 141 PD patients followed at the University Hospital of Modena, Italy from 1 March 2020 to 31 December 2021. The diagnosis of COVID-19 was performed through nasopharyngeal swab RT–PCR testing. Duration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding measured the time elapsed from diagnosis of COVID-19 to one or two (if available) negative nasopharyngeal PCR tests. Median and interquartile range or mean and standard deviation were used for continuous variables and percentage for categorical variables. A P-value &lt;0.05 was considered statistically significant.

RESULTS

During the pandemic, 18 out of 141 (12.7%) patients receiving PD dialysis contracted COVID-19. Median age was 60 (50.2–66.5) years with a predominance of males (72.2%)

The percentage of patients on APD accounted for 33.3%.

The infection was symptomatic in out of 18 (94.4%) patients. Fever (94.4%) and cough (55.6%) were the most common symptoms. Viral shedding, traced with nasopharyngeal swabs lasted 26 (14.5–3.5) days. Two patients were inactive on the waiting list for kidney transplantation for a mean of 43 ± 1.4 days.

COVID-19 caused hospital admission of seven (38.9%) patients. During hospitalization two (11.1%) patients switched from PD to HD for ultrafiltration failure and inadequate solute clearance and two (11.1%) died for septic shock with multiorgan failure. In our cohort of patients, excess death due to COVID-19 was 22.2%.

Half of the patients contracted the infection before the availability of SARS-CoV-2 vaccine. There were no statistically significant differences between vaccinated and unvaccinated patients in terms of symptoms, viral shedding and hospital admission or (Table 1). We underline that COVID-19 was fatal only in two unvaccinated patients.

CONCLUSION

This study reports the monocentric experience of a large PD center during the COVID-19 pandemic. COVID-19 was symptomatic in the majority of patients and led to hospitalization of about 40% of the patients. The rate of symptoms, viral shedding and hospital admission was similar between vaccinated and unvaccinated patients. Two unvaccinated patients died for the severe consequence of COVID-19.

Which criteria should we use to end isolation in hemodialysis patients with COVID-19?

Safe and timely discontinuation of quarantine of in-center hemodialysis (HD) patients with a previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a challenging issue for the nephrological community because current guidelines for ending isolation do not mention dialysis patients. To prevent potentially fatal outbreaks of coronavirus disease 2019 (COVID-19), a cautionary approach has been adopted by most dialysis units. The criteria for ending the isolation in the HD population generally coincide with those recommended for immunocompromised people. Thus, a test-based strategy relying on two consecutive negative reverse transcriptase-polymerase chain reaction (RT-PCR) nasopharyngeal swabs has been adopted to terminate quarantine. This strategy has the disadvantage of prolonging isolation as RT-PCR positivity does not equate to SARS-CoV-2 infectivity. Consequentially, prolonged positivity of SARS-CoV-2 results in excessive workload for the HD staff who must face an increasing number of COVID-19 patients requiring isolation. This condition leads also to serious implications for the patients and their households including work productivity loss, postponement of health-care appointments and an increased risk of COVID-19 reinfection. To counteract this problem, other diagnostic tests should be used to provide the best care to HD patients. Recent results seem to encourage the use of RT-PCR cycle threshold (Ct) values and rapid antigen tests given their better correlation with cell culture for SARS-CoV-2 than RT-PCR testing. Here, we provide an overview of the current scientific evidence on the tests used to verify the infectiousness of the virus in order to stimulate the nephrological community to adopt a streamlined and pragmatic procedure to end isolation in COVID-19 patients on HD.

Reactogenicity of COVID-19 vaccine in hemodialysis patients: a single-center retrospective study

Introduction: Some hemodialysis patients are reluctant to undergo COVID-19 vaccination for the fear of developing adverse events (AEs). The aim of this study was to verify the safety of the mRNA-1273 vaccine in hemodialysis patients. Methods: We conducted a retrospective analysis of in-center hemodialysis patients who underwent mRNA-1273 vaccine from March 1st to April 30th, 2021. All AEs occurring after the first and the second doses were collected and classified as local or systemic. Results: Overall, 126 patients on chronic maintenance dialysis without a prior COVID-19 diagnosis were vaccinated with two doses of mRNA-1273 vaccine. Mean age was 68 (IQR, 54,7-76) years and 53.6% of patients were aged ≥65 years. During the observational period of 68 (IQR, 66-70) days, AEs occurred in 57.9% and 61.9% of patients after the first dose and second dose, respectively. The most common AEs were: injection-site pain (61.9%), erythema (4.8%), itching (4.8%), swelling (16.7%), axillary swelling/tenderness (2.4%), fever (17.5%) headache (7.9%), fatigue (23.8%), myalgia (17.5%), arthralgia (12.7%), dyspnoea (2.4%), nausea/vomiting (7.1%), diarrhoea (5.6%), shivers (4%) and vertigo (1.6%). The rates of local AEs were similar after the first and second doses (P=0.8), whereas systemic AEs occurred more frequently after the second dose (P=0.001). Fever (P=0.03), fatigue (P=0.02) and nausea/vomiting (P=0.03) were significantly more frequent after the second dose of the vaccine. There were no age-related differences in the rate of AEs. Overall, vaccine-related AEs in hemodialysis patients seem to be lower than in the general population. Conclusion: The RNA-1273 vaccine was associated with the development of transient AEs after the first and second doses in patients on chronic maintenance hemodialysis. They were mostly local, whereas systemic AEs were more prevalent after the second dose. Overall, all AEs lasted for a few days, without any apparent sequelae.

Immunosuppressive therapy reduction and early post-infection graft function in kidney transplant recipients with COVID-19

Background: Kidney transplant (KT) recipients with COVID-19 are at high risk of poor outcomes due to the high burden of comorbidities and immunosuppression. The effects of immunosuppressive therapy (IST) reduction are unclear in patients with COVID-19. Methods: A retrospective study on 45 KT recipients followed at the University Hospital of Modena (Italy) who tested positive for COVID-19 by RT-PCR analysis. Results: The median age was 56.1 years (interquartile range,[IQR] 47.3-61.1), with a predominance of males (64.4%). Kidney transplantation vintage was 10.1 (2.7-16) years, and 55.6 % of patients were on triple IST before COVID-19. Early immunosuppression minimization occurred in 27 (60%) patients (reduced-dose IST group) and included antimetabolite (88.8%) and calcineurin inhibitor withdrawal (22.2%). After SARS-CoV-2 infection, 88.9% of patients became symptomatic and 42.2% required hospitalization. One patient experienced irreversible graft failure. There were no differences in serum creatinine level and proteinuria in non-hospitalized patients before and post-COVID-19, whereas hospitalized patients experienced better kidney function after hospital discharge (P=0.019). Overall mortality was 17.8%. without differences between full- and reduced-dose IST. Risk factors for death were age (odds ratio [OR]: 1.19; 95%CI: 1.01-1.39), and duration of kidney transplant (OR: 1.17; 95%CI: 1.01-1.35). One KT recipient developed IgA glomerulonephritis and two ones experienced symptomatic COVID-19 after primary infection and SARS-CoV-2 mRNA vaccine, respectively. Conclusions: Despite the reduction of immunosuppression, COVID-19 affected the survival of KT recipients. Age of patients and time elapsed from kidney transplantation were independent predictors of death . Early kidney function was favorable in most survivors after COVID-19.

Ethical challenges in managing unvaccinated patients receiving chronic in-center hemodialysis

Insufficient vaccine coverage and dominance of the more transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are the leading causes of the continued spread of coronavirus disease 2019 (COVID-19) worldwide. To curb the surge in infections, COVID-19 vaccination has been advocated as a priority measure, especially for frail populations and people at high risk of exposure. Patients on in-centre maintenance haemodialysis (HD) embody both conditions. They are at high risk of severe COVID-19 consequences due to their advanced age and weakened immune system and carry an increased risk of SARS-CoV-2 transmission within shared dialysis rooms and public vehicles. Vaccination of the entire HD population is therefore the most effective strategy to protect patients from the dire consequences of COVID-19. Unfortunately, a minority of patients still express COVID-19 vaccine hesitancy. The management of this group of patients, who have the full right to HD treatment, poses demanding problems from a patient safety perspective. The placement of unvaccinated patients within the dialysis room and the protection of all vaccinated patients are some of the most urgent problems the nephrologist faces during the COVID-19 pandemic. In light of these COVID-19-driven changes, an ethical reflection on the management of unvaccinated patients appears crucial to act responsibly and contribute to the health promotion of dialysis patients.

Methicillin-Resistant Staphylococcus aureus Peritonitis due to Hematogenous Dissemination from Central Venous Catheter in a Maintenance Dialysis Patient

Staphylococcus aureus is a Gram-positive bacterium commonly associated with severe infections in hospitalized patients. S. aureus produces many virulence factors leading to local and distant pathological processes. Invasiveness of S. aureus generally induces metastatic infections such as bacteremia, infective endocarditis, osteomyelitis, arthritis, and endophthalmitis. Peritoneal localization from extra-abdominal infection can be a potential consequence of S. aureus infection. Two cases of metastatic peritonitis have been described in patients on peritoneal dialysis with concomitant peripheral vascular catheter-related bloodstream infection. We reported a case of peritoneal metastatic infection caused by methicillin-resistant Staphylococcus aureus (MRSA) in a patient on maintenance hemodialysis. A 37-year-old man was admitted with fever and chill due to jugular central vascular catheter (CVC)-related bloodstream infection caused by MRSA. CVC was placed after switching the patient from peritoneal dialysis to hemodialysis for scarce adherence to fluid restriction. Detection of MRSA on the peritoneal effluent combined with a total white blood cell count of 554 cells/mm³ prompted the diagnosis of satellite MRSA peritonitis. Antibiotic treatment with daptomycin and simultaneous CVC and peritoneal catheter removal resolved the infectious process. No further metastatic localizations were detected elsewhere. In conclusion, S. aureus can induce metastatic infections far from the site of primary infection. As reported in this case, peritonitis can be secondary to the hematogenous dissemination of S. aureus especially in hospitalized patients having a central line.

The frail world of haemodialysis patients in the COVID-19 pandemic era: a systematic scoping review

BACKGROUND

Patients undergoing in-centre haemodialysis (HD) are particularly exposed to the dire consequences of COVID-19. The present systematic scoping review aims to identify the extent, range, and nature of articles related to COVID-19 and maintenance HD: it reports specifically the prevalence of the COVID-19 pandemic in the HD population, implementation of strategies for the prevention, mitigation and containment of the COVID-19 pandemic in HD centres, demographic and clinical characteristics, and outcomes of the pediatric and adult HD patients.

METHODS

A multi-step systematic search of the literature in Pubmed, Scopus, Ovid Medline, Embase and Web of Science, published between December 1, 2019, and January 30, 2021 was performed. Two authors separately screened the titles and abstracts of the documents and ruled out irrelevant articles. A report of the papers that met inclusion criteria was performed; then, a descriptive analysis of the characteristics of the included articles and a narrative synthesis of the results were performed.

RESULTS

The review process ended with the inclusion of 145 articles. Most of them were based on single-centre experiences, which spontaneously developed best practices. Most studies were conducted in high-income countries (69.7%) and a part of them (9.6%) were not in English. Prevalence of COVID-19 among dialysis patients accounted for 0%-37.6%. Preventive measures were reported in 54% of the included articles, with particular emphasis on education, triage, hygiene, and containment measures. Patients experienced a heterogeneous spectrum of symptoms that led 35%-88.2% of them to hospital admission. Median and mean hospital length of stay ranged from 8 to 28.5 and 16.2 to 22 days, respectively. Admission to intensive care units varied widely across studies (from 2.6% to 70.5%) and was associated with high mortality (42.8%-100%). Overall, prognosis was poor in 0%-47% of the hospitalized patients.

CONCLUSIONS

This systematic scoping review provides an overview of the current knowledge on the impact of COVID-19 on the frail world of HD patients. Furthermore, it may help to implement the existing strategies of COVID-19 prevention and provide a list of unmet needs (safe transport, testing, shelter). Finally, it may be a stimulus for performing systematic reviews and meta-analyses which will form the basis for evidence-based guidelines.

One-year persistence of neutralizing anti-SARS-CoV-2 antibodies in dialysis patients recovered from COVID-19

The immunological mechanisms that modulate immune response to SARS-CoV-2 infection remain elusive. Little is known on the magnitude and the durability of antibody response against COVID-19. There is consensus that patients with immune dysfunction, such as dialysis patients, may be unable to mount a robust and durable humoral immunity after infections. Recent studies showed that dialysis patients seroconverted after COVID-19, but data on the durability of the immune response are missing. We reported the data of a durable anti-spike protein seroconversion after natural SARS-CoV-2 infection in three patients on hemodialysis with a mean age of 67.2 ± 13.8 years. A mean antibody titer of 212.6 ± 174.9 UA/ml (Liaison®, DiaSorin) was found after one year (range, 366-374 days) from the diagnosis of COVID-19. In conclusion, this case series provided evidence that patients receiving hemodialysis who recovered from severe COVID-19 were able to mount a long-lasting immune response against SARS-CoV-2. Although the protective capacity of this long-term immunity remains to be determined, these patients did not report signs of reinfection after recovery from COVID-19.

Incidence, risk factors and outcome of acute kidney injury (AKI) in patients with COVID-19

Background

Acute kidney injury (AKI) is a severe complication of coronavirus disease-2019 (COVID-19). This study aims to evaluate incidence, risk factors and case-fatality rate of AKI in patients with COVID-19.

Methods

We reviewed the health medical records of 307 consecutive patients with COVID-19 hospitalized at the University Hospital of Modena, Italy.

Results

AKI was diagnosed in 69 out of 307 (22.4%) COVID-19 patients. Stages 1, 2, or 3 AKI accounted for 57.9%, 24.6% and 17.3%, respectively. AKI patients had a mean age of 74.7 ± 9.9 years. These patients showed higher serum levels of the main markers of inflammation and higher rate of severe pneumonia than non-AKI patients. Kidney injury was associated with a higher rate of urinary abnormalities including proteinuria (0.44 ± 0.85 vs 0.18 ± 0.29 mg/mg; P =  < 0.0001) and microscopic hematuria (P = 0.032) compared to non-AKI patients. Hemodialysis was performed in 7.2% of the subjects and 33.3% of the survivors did not recover kidney function after AKI. Risk factors for kidney injury were age, male sex, CKD and higher non-renal SOFA score. Patients with AKI had a mortality rate of 56.5%. Adjusted Cox regression analysis revealed that COVID-19-associated AKI was independently associated with in-hospital death (hazard ratio [HR] = 4.82; CI 95%, 1.36–17.08) compared to non-AKI patients.

Conclusion

AKI was a common and harmful consequence of COVID-19. It manifested with urinary abnormalities (proteinuria, microscopic hematuria) and conferred an increased risk for death. Given the well-known short-term sequelae of AKI, prevention of kidney injury is imperative in this vulnerable cohort of patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02092-x.

Monoclonal B lymphocytosis in a kidney transplant recipient

Monoclonal B lymphocytosis (MBL) is a lymphoproliferative condition characterised by expansion of a B-cell clone in peripheral blood, with an often indolent clinical course. The presence of a B clonal population alone is several hundred times more common in the general population than chronic lymphocytic leukaemia and other non-Hodgkin's lymphoma subtypes, it usually does not represent a malignant condition and it requires follow-up only, without specific treatment. There are few studies describing MBL in solid organ transplant recipients, thus, the concern is raised when enrolling MBL affected subjects in waiting lists. We report the experience of a patient affected by MBL who underwent kidney transplantation, with particular attention to preoperative screening and immunosuppressants impact on post-transplant lymphoproliferative disease risk, to aid clinicians in the evaluation process of transplant candidates affected by similar conditions.

Acid base disorders in patients with COVID-19

Purpose

Acid–base derangement has been poorly described in patients with coronavirus disease 2019 (COVID-19). Considering the high prevalence of pneumonia and kidneys injury in COVID-19, frequent acid–base alterations are expected in patients admitted with SARS-Cov-2 infection. The study aimed to assess the prevalence of acid–base disorders in symptomatic patients with a diagnosis of COVID-19.

Methods

The retrospective study enrolled COVID-19 patients hospitalized at the University Hospital of Modena from 4 March to 20 June 2020. Baseline arterial blood gas (ABG) analysis was collected in 211 patients. In subjects with multiple ABG analysis, we selected only the first measurement. A pH of less than 7.37 was categorized as acidemia and a pH of more than 7.43 was categorized as alkalemia.

Results

ABG analyses revealed a low arterial partial pressure of oxygen (PO₂, 70.2 ± 25.1 mmHg), oxygen saturation (SO₂, 92%) and a mild reduction of PO₂/FiO₂ ratio (231 ± 129). Acid–base alterations were found in 79.7% of the patient. Metabolic alkalosis (33.6%) was the main alteration followed by respiratory alkalosis (30.3%), combined alkalosis (9.4%), respiratory acidosis (3.3%), metabolic acidosis (2.8%) and other compensated acid–base disturbances (3.6%). All six patients with metabolic acidosis died at the end of the follow-up.

Conclusion

Variations of pH occurred in the majority (79.7%) of patients admitted with COVID-19. The patients experienced all the type of acid–base disorders, notably metabolic and respiratory alkalosis were the most common alterations in this group of patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-021-02855-1.

FC 025ACID BASE DISORDERS IN COVID-19

Background and Aims

Acid-base disorders are common in severely ill patients and reflect the severity of the underlying pathologic process. The incidence and effects of acid-base derangement in COVID-19 patients have been poorly evaluated until now. Tropism of the virus for the lungs and kidneys may theoretically lead to frequent acid-base alterations due to pneumonia and kidney injury, respectively. To verify the derangement of acid-base disorders in COVID-19, we investigated the distribution and the impact of acid-base disorders on the survival of symptomatic patients with a diagnosis of COVID-19.

Method

We retrospectively collected data from electronic charts of all COVID-19 patients hospitalized at the University Hospital of Modena from 4 March to 20 June 2020.

Arterial blood gas (ABG) analysis was required to monitor pulmonary gas exchange and acid-base status. A pH of less than 7.37 was categorized as acidemia and a pH of more than 7.42 was categorized as alkalemia.

211 patients were included in the study population. In patients with multiple ABG analyses, we selected only the first measurement.

Results

The estimated mean age of the population was 64.7 ±15,3 years with a high predominance of males (71.6%). Half of the population referred dyspnea and 61.4% at physical examination. Most patients (82.6%) were on oxygen therapy when ABG analysis was performed. Overall, ABG analyses revealed acute respiratory compromise manifesting with a low arterial partial pressure of oxygen (P0₂, 70.2±25.1 mmHg), oxygen saturation (SO₂, 92%) and a mild reduction of PO₂/FiO₂ ratio (231±129).

Acid-base disturbance was found in the 79.7% of the patients, and contrary to our expectation, metabolic alkalosis (33.6%) was the main alteration followed by respiratory alkalosis (30.3%), combined alkalosis (9.4%) respiratory acidosis (3.3%) metabolic acidosis (2.8%) and other compensated acid-base disturbances (3.6%). ANOVA with post hoc Tukey, revealed statistically significant differences in age, sex, serum level of K, Na, bicarbonate, creatinine of PCO₂, PO2/FiO₂ ratio, CKD, symptoms (caught, diarrhea) and fatality rate among groups.

Metabolic acidosis was associated with death (HR=8.2; CI 95%, 1,93-32,39; P<0.004), after adjustment for lung injury (PaO₂/FiO₂ ratio) tissue hypoperfusion (lactate) and renal involvement (estimated as GFR< 60 ml/min or development of acute kidney injury), Pathological pH (alkalosis or acidosis), variations of PCO₂ or hypobicarbonatemia were not associated with mortality in our study population. Metabolic acidosis occurred in patients with a mean creatinine of 4.5±4.5 mg/dl. Notably, 33.3% of patients were on hemodialysis, 33.3% developed COVID-19-associated acute kidney injury and 33.3% had a GFR <60 ml/min. Patients with metabolic acidosis had the highest death-fatality rate (100%) after 7±5.6 days from admission, 50% died of acute respiratory distress syndrome and 50% of septic shock.

Conclusion

In conclusion, all kinds of acid-base alterations were found in patients with COVID-19. Metabolic and respiratory alkalosis were the most common acid-base disorders, whereas metabolic acidosis was the only acid-base disturbance associate with poor outcome in our cohort of patients.

MO183TELEMEDICINE AS A MODALITY OF HEALTH CARE DELIVERY FOR PATIENTS WITH SEVERE CHRONIC KIDNEY DISEASE DURING COVID-19 PANDEMIC

Background and Aims

Telemedicine is a new modality of care delivery. Over the last months, it has been used to deliver health care to outpatients with chronic kidney disease (CKD) during COVID-19 pandemic. However, experience of telemedicine in patients with severe CKD is scarce and there are not reassuring data about its efficacy in improving patients’ outcome. To evaluate the efficacy and the outcome profile of telemedicine in people with severe CKD, we reviewed all data of outpatients with severe kidney impairment who underwent nephrological evaluation during the first wave of this pandemic. In particular, outcomes of the ambulatory activity (urgent-start dialysis, late referral and modalities of dialysis initiation) were compared to 2019 ambulatory activity.

Method

Outpatients with severe chronic kidney disease included in the ambulatory program called “Pre-Dialysis Program were enrolled in a retrospective study. We reviewed all electronic charts of patients who underwent nephrological follow-up from 9th March to June 21st, 2020 (15 weeks in total) at the University Hospital of Modena, Italy. Extension of the observation period to 30th September 2020 allowed us to determine the long-term effects of telemedicine on the rate of urgent-star dialysis, late referral, and modalities of dialysis initiation.

Results

During 15 weeks of follow-up, 186 nephrological visits were performed (Table) They were subdivided into telemedicine visits (56.5%) and in-person visits (43.5%). Overall, mean age of patients was 71.7±13.1 years with a prevalence of male (60.2%). Patients who received telemedicine visits had a statistically significant lower sCr (3.7±1.2 vs 4.5±1.5 mg/dl; P=0.0001) and higher eGFR level (14.7±6.02 vs 12.16±5.8 ml/min; P=0.002) than patients followed in the ambulatory setting. A high prevalence of patients with CKD stage 5 was monitored by in-person visits (P=0.0001). Patients followed by telemedicine had a clinical profile including a lower weight (P=0.007) and better control of metabolic acidosis (P=0.039) than the counterpart.

Changes in domiciliary therapy occurred more frequently in patients monitored in the ambulatory setting (P=0.036). Statistically significant differences were encountered in the prescription of diuretics (P=0.002), sodium bicarbonate (P=0.043), antihypertensive drugs (P=0.001) and uric acid-lowering agents (P=0.046). During the 15-week period in 2019, 214 visits were performed (+13% compared to 2020). The vast majority of these visits were conducted in the hospital setting (210 out of 214; 98.2%). The severity of CKD was similar between patients, without statistically significant difference in the rate of patients in CKD stage III (P=0.7), stage IV (0.388) and stage V (P=0.593).

Implementation of telemedicine to in-person visits during COVID-19 pandemic did not change the outcomes of patients. Short-term follow-up showed a similar rate in urgent-start dialysis (P=0.361), late referral (P=1), and HD (P=0.875) or PD initiation (P=0.661). Similar results were seen also at the end of the extended follow-up.

Conclusion

Implementation of telemedicine has been fundamental to maintain a high level of care in CKD patients during the COVID-19 pandemic. Telemedicine services in combination with in-person visits have contributed to the delivery of clinical monitoring in a group of patients with severe and progressive CKD. No differences have been identified in terms of rate of unplanned dialysis, late referral, and modality of dialysis initiation.

Twenty-four-hour serum creatinine variation is associated with poor outcome in the novel coronavirus disease 2019 (COVID-19) patients

Background

The prognostic value of within-day sCr variation serum creatinine variation is unknown in the setting of the novel coronavirus disease 2019 (COVID-19). We evaluated the prognostic significance of 24-hour serum creatinine variation in COVID-19 patients.

Methods

A monocentric retrospective analysis was conducted in COVID-19 patients not admitted to the intensive care unit. Three groups were subdivided based on 24 hours serum creatinine variation from admission. In the stable kidney function group, 24-hour serum creatinine variation ranged from +0.05 to –0.05 mg/dL; in the decreased kidney function group, 24-hour serum creatinine variation was >0.05 mg/dL; in the improved kidney function group, 24-hour serum creatinine variation was <–0.05 mg/dL.

Results

The study population included 224 patients with a median age of 66.5 years and a predominance of males (72.3%). Within 24 hours of admission, renal function remained stable in 37.1% of the subjects, whereas it displayed improved and deteriorated patterns in 45.5% and 17.4%, respectively. Patients with decreased kidney function were older and had more severe COVID-19 symptoms than patients with stable or improved kidney function. About half of patients with decreased kidney function developed an episode of acute kidney injury (AKI) during hospitalization. Decreased kidney function was significantly associated with AKI during hospitalization (hazard ratio [HR], 4.6; 95% confidence interval [CI], 1.9–10.8; p < 0.001) and was an independent risk factor for 30-day in-hospital mortality (HR, 5.5; 95% CI, 1.1–28; p = 0.037).

Conclusion

COVID-19 patients with decreased kidney function within 24 hours of admission were at high risk of AKI and 30-day in-hospital mortality.

Rituximab or Cyclophosphamide in the Treatment of Membranous Nephropathy: The RI-CYCLO Randomized Trial

BACKGROUND

A cyclic corticosteroid-cyclophosphamide regimen is the first-line therapy for membranous nephropathy. Compared with this regimen, rituximab therapy might have a more favorable safety profile, but a head-to-head comparison is lacking.

METHODS

We randomly assigned 74 adults with membranous nephropathy and proteinuria >3.5 g/d to rituximab (1 g) on days 1 and 15, or a 6-month cyclic regimen with corticosteroids alternated with cyclophosphamide every other month. The primary outcome was complete remission of proteinuria at 12 months. Other outcomes included determination of complete or partial remission at 24 months and occurrence of adverse events.

RESULTS

At 12 months, six of 37 patients (16%) randomized to rituximab and 12 of 37 patients (32%) randomized to the cyclic regimen experienced complete remission (odds ratio [OR], 0.4; 95% CI, 0.13 to 1.23); 23 of 37 (62%) receiving rituximab and 27 of 37 (73%) receiving the cyclic regimen had complete or partial remission (OR, 0.61; 95% CI, 0.23 to 1.63). At 24 months, the probabilities of complete and of complete or partial remission with rituximab were 0.42 (95% CI, 0.26 to 0.62) and 0.83 (95% CI, 0.65 to 0.95), respectively, and 0.43 (95% CI, 0.28 to 0.61) and 0.82 (95% CI, 0.68 to 0.93), respectively, with the cyclic regimen. Serious adverse events occurred in 19% of patients receiving rituximab and in 14% receiving the cyclic regimen.

CONCLUSIONS

This pilot trial found no signal of more benefit or less harm associated with rituximab versus a cyclic corticosteroid-cyclophosphamide regimen in the treatment of membranous nephropathy. A head-to-head, pragmatic comparison of the cyclic regimen versus rituximab may require a global noninferiority trial.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Rituximab versus Steroids and Cyclophosphamide in the Treatment of Idiopathic Membranous Nephropathy (RI-CYCLO), NCT03018535.

Hypokalemia in Patients with COVID-19

BACKGROUND

Patients with COVID-19 experience multiple clinical conditions that may cause electrolyte imbalances. Hypokalemia is a concerning electrolyte disorder closely associated with severe complications. This study aimed to estimate prevalence, risk factors and outcome of hypokalemia in a cohort of patients with confirmed COVID-19.

METHODS

A retrospective analysis was conducted on 290 non-ICU admitted patients with COVID-19 at the tertiary teaching hospital of Modena, Italy, from February 16 to April 14, 2020.

RESULTS

Hypokalemia was detected in 119 out of 290 patients (41%) during hospitalization. Mean serum potassium was 3.1 ± 0.1 meq/L. The majority of patients (90.7%) patients experienced only a mild decrease in serum potassium level (3-3.4 mEq/L). Hypokalemia was associated with hypocalcemia, which was detected in 50% of subjects. Urine potassium-to-creatinine ratio, measured in a small number of patients (n = 45; 36.1%), revealed an increase of urinary potassium excretion in most cases (95.5%). Risk factors for hypokalemia were female sex (odds ratio (OR) 2.44; 95% CI 1.36-4.37; P 0.003) and diuretic therapy (OR 1.94, 95% CI 1.08-3.48; P 0.027). Hypokalemia, adjusted for sex, age and SOFA score, was not associated with ICU transfer (OR 0.52; 95% CI 0.228-1.212; P = 0.131), in-hospital mortality (OR, 0.47; 95% CI 0.170-1.324; P = 0.154) and composite outcome of ICU transfer or in-hospital mortality (OR 0.48; 95% CI 0.222-1.047; P = 0.065) in our cohort of patients.

CONCLUSIONS

Hypokalemia was a frequent disorder in subjects with COVID-19. Female sex and diuretic therapy were identified as risk factors for low serum potassium levels. Hypokalemia was unrelated to ICU transfer and death in this cohort of patients.

Hybrid dialysis: a promising strategy to reduce hospital access during the SARS-CoV-2 pandemic

In March 2020, a 74-year-old man affected by end-stage renal disease and on peritoneal dialysis was referred to an emergency room in Modena, Northern Italy, due to fever and respiratory symptoms. After ruling out COVID-19 infection, a diagnosis of chronic obstructive pulmonary disease exacerbation was confirmed and he was thus transferred to the nephrology division. Physical examination and blood tests revealed a positive fluid balance and insufficient correction of the uraemic syndrome, although peritoneal dialysis prescription was maximised. After discussion with the patient and his family, the staff decided to start hybrid dialysis, consisting of once-weekly in-hospital haemodialysis and home peritoneal dialysis for the remaining days. He was discharged at the end of the antibiotic course, after an internal jugular vein central venous catheter placement and the first haemodialysis session. This strategy allowed improvement of depuration parameters and avoidance of frequent access to the hospital, which is crucial in limiting exposure to SARS-CoV-2 in an endemic setting.

Evaluation of the Classification Accuracy of the Kidney Biopsy Direct Immunofluorescence through Convolutional Neural Networks

BACKGROUND AND OBJECTIVES

Immunohistopathology is an essential technique in the diagnostic workflow of a kidney biopsy. Deep learning is an effective tool in the elaboration of medical imaging. We wanted to evaluate the role of a convolutional neural network as a support tool for kidney immunofluorescence reporting.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

High-magnification (×400) immunofluorescence images of kidney biopsies performed from the year 2001 to 2018 were collected. The report, adopted at the Division of Nephrology of the AOU Policlinico di Modena, describes the specimen in terms of "appearance," "distribution," "location," and "intensity" of the glomerular deposits identified with fluorescent antibodies against IgG, IgA, IgM, C1q and C3 complement fractions, fibrinogen, and κ- and λ-light chains. The report was used as ground truth for the training of the convolutional neural networks.

RESULTS

In total, 12,259 immunofluorescence images of 2542 subjects undergoing kidney biopsy were collected. The test set analysis showed accuracy values between 0.79 ("irregular capillary wall" feature) and 0.94 ("fine granular" feature). The agreement test of the results obtained by the convolutional neural networks with respect to the ground truth showed similar values to three pathologists of our center. Convolutional neural networks were 117 times faster than human evaluators in analyzing 180 test images. A web platform, where it is possible to upload digitized images of immunofluorescence specimens, is available to evaluate the potential of our approach.

CONCLUSIONS

The data showed that the accuracy of convolutional neural networks is comparable with that of pathologists experienced in the field.

Erratum: SARS-CoV-2 infection in dialysis patients in northern Italy: a single-centre experience

[This corrects the article DOI: 10.1093/ckj/sfaa084.][This corrects the article DOI: 10.1093/ckj/sfaa084.].

[The definition of chronic kidney disease in a context of aging population]

Chronic kidney disease (CKD) is a progressively chronic disease that carries a high burden of morbidity and mortality and is associated with significant healthcare utilization and costs. Recent trends shown that the prevalence of CKD is stable in Europe and USA, whereas tends to decline in some countries with a high standard of care. According to international guidelines, chronic kidney disease (CKD) is defined as the presence of kidney damage or a glomerular filtration rate (eGFR) less than 60 ml/min. This staging method has a main drawback, its imprecise assessment of renal function at the extremes of the age bracket: the use of a fixed threshold value (glomerular filtration rate [GFR <60 ml /min]) to define chronic renal failure appears an imprecise measure in the young and in the elderly. In these two groups, in fact, the measurement of GFR is difficult to categorize in a "rigid" system of classification. The reduction of the GFR with aging is due to a complex process that leads to a steady reduction of the functioning nephrons over 40 years of age. Taken together, these findings should spur us to adopt a new definition of CKD. An age-adapted definition of CKD could be a good solution to avoid a diagnosis of CKD in elderly patients (GFR >45 ml/min) when there are no prognostic implications on survival. The adoption of this new definition would also reduce the high prevalence of the disease in the general population, with a beneficial reduction of the costs associated with monitoring a mildly decreased eGFR.

[The underlying cause of kidney disease is often unknown in dialysis patients: a possible genomic approach]

As much as 16-17% European and American patients on renal replacement therapy do not have a conclusive diagnosis of the cause of their renal failure. This may have important implications on the types of morbidity they can develop in case of systemic diseases with extrarenal involvement, or recurrent renal diseases in transplanted patients. A better knowledge of the underlying disease can have important prognostic and therapeutic repercussions. In this study we evaluated the rate of uremic patients who can benefit from a genomic diagnostic approach. Patients liable to a future genomic diagnostic study were selected based on two criteria: (i) age of dialysis entry less or equal to 55 years, and (ii) presence of a non-conclusive diagnosis. Based on the data extracted from the REGDIAL registry, we analyzed 534 patients undergoing renal replacement therapy. We identified 300 patients with age of entry into replacement therapy <55 years (56.2% of the overall study population). Among these, we identified 107 patients with missing or inconclusive diagnosis, which was equal to 20% of the overall population. Of these patients, 32.8% reported a positive family history of kidney disease. This study confirms that a significant proportion of patients on renal replacement therapy do not have an etiological diagnosis and may be subject to a genomic evaluation. With the increasing availability of genomic sequencing technology and the falling of related costs, nephrologists will be increasingly inclined to incorporate clinical genetic testing into their diagnostic armamentarium. There is therefore a need for in-depth, multicenter studies aimed at developing evidence-based guidelines, clear indications and at confirming the usefulness of genetic testing in nephrology.

Long-term effects of COVID-19 in a patient on maintenance dialysis

Coronavirus infectious disease (COVID-19) is a novel respiratory infection highly associated with severe complications in elderly subjects affected by cardiovascular disease. Patients on maintenance dialysis are exceptionally vulnerable because most of them are old and have multiple comorbidities. We report the complex clinical course of SARS-CoV-2 infection in a patient on maintenance dialysis who presented with fever and lung edema. After 41 days from the primary infection, the clinically recovered patient experienced symptomatic reactivation of SARS-COV-2 infection documented by positive polymerase chain reaction (PCR) result on nasal/oropharyngeal swab along with immunoglobulin M seroconversion. The recurrence of PCR positivity forced us to perform hemodialysis in a separate isolation room for a prolonged period of time. Close monitoring of previously infected patients and restructuring of dialysis facilities are necessary to avoid new outbreaks of this concerning disease.

Peritoneal dialysis in the time of coronavirus disease 2019

In the current setting of global containment, peritoneal dialysis (PD) and home haemodialysis are the best modalities of renal replacement therapy (RRT) to reduce the rate of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Considering the shorter and easier training programme of PD compared to home haemodialysis, PD appears a practical solution for patients with end-stage renal disease to reduce the risk of hospital-acquired infection. PD offers the advantage of minimizing the risk of viral transmission through interpersonal contact that commonly occurs during the haemodialysis session and while travelling from home to the haemodialysis facility using public transport services. To overcome barriers to health care access due to the containment measures for this emerging disease, telemedicine is a useful and reliable tool for delivering health care without exposing patients to the risk of contact. However, novel issues including handling of potentially infected dialysate, caregivers’ infectious risk and adequacy of PD in critically ill patients with acute respiratory distress syndrome remain to be clarified. In conclusion, PD should be preferred to the other modalities of RRT during the coronavirus disease 2019 (COVID-19) outbreak because it can be a solution to cope with the increased number of infected patients worldwide.

COVID-19 pneumonia in a kidney transplant recipient successfully treated with tocilizumab and hydroxychloroquine

Coronavirus disease 2019 (COVID-19) pneumonia has been poorly reported in solid organ transplanted patients; prognosis is uncertain and best management unclear. We describe the case of a 61-year-old kidney transplant recipient with several comorbidities who was hospitalized and later received a diagnosis of COVID-19 pneumonia; the infection was successfully managed with the use of hydroxychloroquine and a single administration of tocilizumab, after immunosuppression reduction; the patient did not require mechanical ventilation. During the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, transplant clinicians should be readily informed about new cases of COVID-19 pneumonia in solid organ transplant recipients, with focus on therapeutic strategies employed and their outcome.

SARS-CoV-2 infection in dialysis patients in northern Italy: a single-centre experience

Background

Dialysis patients are considered at high risk for COVID-19 and the infection can easily spread in dialysis units.

Methods

We conducted an observational single-centre cohort study to describe clinical characteristics, treatments and outcomes of dialysis patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We tested patients who presented symptoms or had contact with a confirmed case. We enrolled 15 patients positive for SARS-CoV-2.

Results

We tested 37 of 306 dialysis patients. Patients with SARS-CoV-2 infection were older (mean age 75.96 ± 11.09 years) and all had comorbidities. At presentation, most had interstitial infiltrates on chest X-ray, three-quarters had leucopenia and none had respiratory insufficiency. During follow-up, there was an increase in serum C-reactive protein and interleukin-6. Eighty percent of patients received supplemental oxygen; none received non-invasive ventilation, one was intubated. Most patients (80%) were treated with oral hydroxychloroquine for a median time of 6.5 days [interquartile range (IQR) 5–14.5] and 40% received azithromycin; two patients received a short course of antivirals and one received a single dose of tocilizumab. Only two patients did not require hospitalization. Of the nine survivors, eight still tested positive for SARS-CoV-2 a median of 19 days (IQR 9.25–23) after diagnosis. Six patients died (case fatality rate 40%) a median of 5.5 days (IQR 1.75–9.75) after diagnosis. The main reported cause of death was respiratory failure related to COVID-19 (five patients).

Conclusions

We report a single-centre experience of SARS-CoV-2 infection in dialysis patients. The disease showed a high case fatality rate and most patients required hospitalization. Survivors show prolonged viral shedding.

P0328DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS) SYNDROME: THE GREAT MIMICKER SECONDARY TO LENALIDOMIDE IN PERITONEAL DIALYSIS

Background and Aims

DRESS syndrome is a rare, idiosyncratic, potentially life-threatening adverse drug reaction, characterized by latent period after intake of the inciting drug (2-6 weeks), fever higher than 38.5°C, skin eruptions (usually pruritic maculopapular rash or diffuse erythematous eruption), eosinophilia (in 66-95% of patients), mononucleosis-like atypical lymphocytes (27-67% of pts), thrombocytopenia, lymphadenopathy (in 54% of pts) and multiple organ involvement. In 50-60% of patients, two or more organs are involved, most frequently liver (hepatomegaly, hepatitis with ALT&gt; 2 times and ALP&gt; 1,5 times the upper limit), kidney (acute interstitial nephritis, most often induced by allopurinol) and lung (interstitial pneumonia). Cardiovascular involvement occurs lately (up to four months after recovery) with myocarditis, decreased LV function and elevated troponin. Different mechanisms have been involved in the pathogenesis of DRESS syndrome, including detoxification defects leading to reactive metabolite formation and subsequent immunological reactions, slow acetylation and reactivation of human herpes, including Epstein-Barr virus and HHV-6. Cacoub et al reported 172 cases of DRESS: the most frequently reported “trigger-drugs” were carbamazepine, allopurinol, sulfasalazine, phenobarbital, nevirapine and HHV-6 infections were positive in 80% of cases. Interestingly, the culprit drug could be able to trigger viral reactivation, inducing a pathogenic anti-viral CD8+ response. According to available literature, the drug should be withdrawn and, in cases of visceral involvement, systemic steroids are indicated (1 mg/kg orally with slow taper over 3-6 months). In severe cases, other therapies include IVIG, plasmapheresis and immunosuppressant drugs.

CASE REPORT A 72-year-old male, affected by ESKD in peritoneal dialysis and hypokinetic heart disease, started lenalidomide for multiple myeloma with bone involvement. After 18 days he presented a violet maculopapular rash involving &gt;50% of his body, fever (38,5 °C), leukopenia with CRP &lt;0,8 mg/dl. Lenalidomide was withdrawn and started oral steroid, anti-histamine and levofloxacin. One week later he was admitted for a syncopal episode. Laboratory tests revealed leukocytosis (12.250/mm), eosinophilia (until 56%, 4.550/mm) and cholestatic-cellular liver damage (ALT 1448 U/l, ALP 308 U/l) requiring albumin infusion.

Extensive infectious and autoimmune workup was negative, including ANA test, immunological liver diseases tests, blood cultures, viral/bacterial tests, except for HHV6 reactivation (420 copies/ml). US abdominal study was negative, while DLCO test showed an important diffusive deficit. ECHO showed a reduced LV ejection.

Skin biopsy demonstrated sparse vacuolization of epidermis and dermal-epidermal inflammation with some eosinophils and CD8+ T cells, suggesting a drug reaction.

For clinic and laboratory features RegiSCAR score system and Japanese consensus group categorized this case as “definite DRESS” respectively with score 6 and 7. So we started IVIG (1 gr/Kg for 2 days) and prednisone with reduced dose for comorbidities (0,8 mg/Kg daily, tapered to 0,6 mg/Kg after 1 week); the patient gradually improved but after 1 week, DRESS syndrome relapsed with rash, elevated GOT and GPT and troponin until 330 ng/l with normal ECG; he has just started steroid bolus and IVIG.

Conclusion

The variety of drugs, the clinical course with slow resolution and relapse and HHV-6 reactivation suggest that drugs cannot be the sole etiology of DRESS. Precise mechanism of lenalidomide in DRESS syndrome is not clear and its immunomodulatory activity could contribute in the hypersensivity reaction. Only few cases are reported in literature, but with the increasing use of lenalidomide a broad workup and a careful approach are important for a fast diagnosis

P0494UNUSUAL CASE OF ACUTE KIDNEY INJURY (HISTOLOGICAL EVALUATION: COLLAPSING GLOMERULOPATHY) IN HEMOPHAGOCYTIC SYNDROME ASSOCIATED WITH NK/T LYMPHOMA

Background and Aims

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome induced by aberrantly activated macrophages and cytotoxic T cells. The primary (genetic) form, caused by mutations affecting lymphocyte cytotoxicity and immune regulation, is most common in children, whereas the secondary (acquired) form is most frequent in adults. Secondary HLH is commonly triggered by infections or malignancies but may also be induced by autoinflammatory/autoimmune disorders, in which case it is called macrophage activation syndrome.

The diagnosis of HLH in adults should be based on the HLH-2004 diagnostic criteria in conjunction with clinical judgment and the patient’s history.

Renal involvement has previously been reported in 24 adult cases, mostly as acute renal failure. Collapsing glomerulopathy is extremely rare with only six previous cases reported in the literature.

Case presentation We report the case of an African man, 31 years old, presented with fever, acute kidney injury: serum creatinine 10.3 mg/dl; urine protein 600 mg/dl, macrohematuria, ANA/ANCA were negative, low serum C3, organomegaly, anemia, thrombocytopenia, hypertriglyceridemia, hypofibrinogenemia, hyperferritinemia, direct and indirect antiglobulin (Coombs) tests were negative, low haptoglobin; elevated LDH; normal partial thromboplatin time. Peripheral blood smear examination reveal few schistocytes. ADAMTS13 activity was found to be 25%. HBV-DNA and HIV were negative. Anticardiolipin antibodies were negative. Lab exam suggested the relapse of an EBV infection and primary mycoplasma infection. Because of uremic symptoms and persisting oliguria we started replacement therapy by hemodialysis. Plasmapheresis was started because of suspected thrombotic microangiopathy. Suprisingly the kidney biopsy was consistent with collapsing glomerulopathy with evidence of tubular injury while the bone marrow biopsy diagnosed an EBV NK/T-Cell lymphoma.

During the course of his hospitalization, the patient suffered high fever. C-reactive protein, WBC and procalcitonin levels were elevated. Antimicrobial agents were initiated, starting with ceftriaxone then upgraded to piperacillin/tazobactam and then the shifted to teicoplanin and meropenem.

Blood, urine and stool cultures were negative.VRE positive, IgM Mycoplasma pneumoniae were positive; EBV PCR on bone marrow blood was positive. Malaria screening was negative. The antibiotic therapy was finally switched to doxycycline as unique agent.

Steroid therapy (dexamethasone daily 40 mg) and IVIG (daily 35g) were initiated then these drug were stopped. CHOP-like regimen ( Etoposide 75 mg/m2, twice a week for two weeks then once a week until the seventh week) and Rituximab (375 mg/m2, once a week for 4 weeks) were initiated and continued for two weeks. Later on the patient died because of sepsis and multi-organ failure.

Conclusions The multidisciplinary approach is very important. Physicians should be aware of HLH, because early recognition may prevent irreversible organ damage and subsequent death.4,5 In adults, HLH-associated mortality remains high, especially in patients with underlying malignancies.

Collapsing glomerulopathy is the most commonly reported finding on renal biopsy. Renal prognosis appears to be poor with most patients remaining dialysis-dependent.

The increased awareness of HLH, together with a more rapid diagnostic workup and new therapeutic approaches, will improve the prognosis of HLH in adults.

ADPKD current management and ongoing trials

Among the diseases that require renal replacement therapy (RRT), ADPKD is the fourth for incidence and prevalence. In Italy, there are at least 32,000 patients affected by ADPKD, of which about 2900 in dialysis. The pure costs of dialysis treatment for the Italian National Health Service can be conservatively estimated at 87 million euros per year. Even a modest slowdown in the evolution of the disease would obtain an important result in terms of reduction of health expenditure. In recent years, many new or repurposed drugs have been evaluated in clinical trials for ADPKD. In this review we will mainly focus on advanced stage clinical trials (phase 2 and 3). We have grouped these studies according to the molecular pathway addressed by the experimental drug or the therapeutic strategy. More than 10 years after the start of the first Phase III clinical trials in ADPKD, the first drug active in slowing disease progression is finally available. It cannot be considered a goal but only the beginning of a journey because of the significant side effects and the high cost of Tolvaptan. An exuberant basic research activity in the field, together with the large number of ongoing protocols, keep the nephrologists and their patients positive with regard to the discovery of new and better therapies in a not-too-distant future.

Rituximab versus steroids and cyclophosphamide for the treatment of primary membranous nephropathy: protocol of a pilot randomised controlled trial

INTRODUCTION

Primary membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. The disease may have different long-term outcomes. After 10 years of follow-up, 35%-50% of the untreated patients with persistent nephrotic syndrome may die or progress to end stage renal disease. The 2012 KDIGO (Kidney Disease Improving Global Outcomes) guidelines recommend that initial therapy should consist of alternating steroids and an alkylating agent for 6 months. Recent observational studies showed that the anti-CD20 antibody rituximab may be effective in inducing remission. We designed a pilot multicentre randomised trial to inform the design of a larger trial testing the efficacy and safety of treatment with steroids and cyclophosphamide versus rituximab in patients with primary MN and heavy proteinuria (>3.5 g/24 hours).

METHODS AND ANALYSIS

This pilot, open-label, two-parallel-arm, randomised clinical trial will enrol 70 patients with primary MN and heavy proteinuria. Patients will be randomised in a 1:1 ratio to either the intervention arm (rituximab) or the active comparator arm (corticosteroid/alkylating-agent therapy). The study will provide estimates of the probability of complete remission of proteinuria and risk of serious side effects at 12 months to inform the design of a larger trial. We will also assess the recruitment potential of each participating centre to address study feasibility.

ETHICS AND DISSEMINATION

The trial received ethics approval from the local ethics boards. We will publish pilot data to inform the design of a larger clinical trial.

TRIAL REGISTRATION NUMBERS

NCT03018535; 2011-006115-59.