Proteinuria in COVID-19: prevalence, characterization and prognostic role

Kidney damage associated with COVID-19: from the acute to the chronic phase

Severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) infection is well established as a systemic disease including kidney damage. The entry point into the renal cell remains the angiotensin-converting enzyme 2 (ACE-2) receptor and the spectrum of renal lesions is broad, with a clear predominance of structural and functional tubular lesions. The most common form of glomerular injury is collapsing glomerulopathy (CG), which is strongly associated with apolipoprotein L1(APOL-1) risk variants. These acute lesions, which are secondary to the direct or indirect effects of SARS-CoV-2, can progress to chronicity and are specific to long COVID-19 in the absence of any other cause. Residual inflammation associated with SARS-CoV-2 infection, in addition to acute kidney injury (AKI) as a transitional state with or without severe histological lesions, may be responsible for greater kidney function decline in mild-to-moderate COVID-19. This review discusses the evidence for renal histological markers of chronicity in COVID-19 patients and triggers of low-grade inflammation that may explain the decline in kidney function in the post-COVID-19 period.

The relation between proteinuria and the severity of COVID-19

BACKGROUND

The association between proteinuria, which is also an indicator of chronic kidney disease (CKD), and coronavirus disease 2019 (COVID-19) severity is unclear.

METHODS

We selected 342 hospitalized patients with COVID-19 diagnosed via polymerase chain reaction testing between February 2020 and October 2022 and who had at least one urinalysis 14-365 days before admission.

RESULTS

Proteinuria before admission was associated neither with oxygen administration nor developing pneumonia in multivariate analysis (odds ratio [OR] 1.03; 95% confidence interval (CI) 0.44-2.40, p = 0.95 and OR 1.01; 95% CI 0.47-2.17, p = 0.98, respectively). Proteinuria on admission was associated both with oxygen administration and developing pneumonia in multivariate analysis (OR 3.29; 95% CI 1.37-7.88, p < 0.01 and OR 3.81; 95% CI 1.68-8.62, p < 0.01, respectively). The percentage of patients with proteinuria on admission was significantly higher than those before admission (37.4% vs. 17.8%; p < 0.01). In the subgroup analysis, proteinuria on admission among patients with eGFR ≥ 60 mL/min/1.73 m2 was associated with both oxygen administration and developing pneumonia (OR 4.86; 95% CI 1.22-19.38, p = 0.03, OR 3.65; 95% CI 1.06-12.58, p = 0.04, respectively). In contrast, proteinuria on admission among patients with eGFR < 60 mL/min/1.73 m2 was associated with developing pneumonia (OR 6.45; 95%CI 1.78-23.35, p = 0.01), not with oxygen administration (OR 3.28; 95% CI 0.92-11.72, p = 0.07).

CONCLUSIONS

Although underlying proteinuria before admission was not associated with COVID-19 severity, proteinuria on admission was associated with oxygen demand and developing pneumonia.

Long-term effect of COVID-19 infection on kidney function among COVID-19 patients followed in post-COVID-19 recovery clinics in British Columbia, Canada

BACKGROUND

We investigated the effect of Post-Acute COVID Syndrome or "long-COVID" on kidney function among patients followed in post-COVID recovery clinics (PCRC) in British Columbia, Canada.

METHODS

Long-COVID patients referred to PCRC between July 2020 to April 2022, aged ≥18 years who had an estimated glomerular filtration rate (eGFR) value recorded at 3 months from the coronavirus disease 2019 (COVID-19) diagnosis (index) date were included. Those requiring renal replacement therapy prior to index date were excluded. Primary outcome was change in eGFR and urine albumin-creatinine ratio (UACR) after COVID-19 infection. The proportion of patients in each of the six eGFR categories (<30, 30-44, 45-59, 60-89, 90-120 and >120 mL/min/1.73 m2) and three UACR categories (<3, 3-30 and >30 mg/mmol) in all of the study time points were calculated. Linear mixed model was used to investigate change in eGFR over time.

RESULTS

The study sample included 2212 long-COVID patients. Median age was 56 years, 51% were male. Half (∼47%-50%) of the study sample had normal eGFR (≥90 mL/min/1.73 m2) from COVID-19 diagnosis to 12 months post-COVID and <5% of patients had an eGFR <30 mL/min/1.73 m2. There was an estimated 2.96 mL/min/1.73 m2 decrease in eGFR within 1 year after COVID-19 infection that was equivalent to 3.39% reduction from the baseline. Decline in eGFR was highest in patients hospitalized for COVID-19 (6.72%) followed by diabetic patients (6.15%). More than 40% of patients were at risk of CKD.

CONCLUSIONS

People with long-COVID experienced a substantial decline in eGFR within 1 year from the infection date. The prevalence of proteinuria appeared to be high. Close monitoring of kidney function is prudent among patients with persistent COVID-19 symptoms.

Association of Neutrophil/Lymphocyte Ratio and Neutrophil/Lymphocyte Platelet Ratio With Acute Kidney Injury in Severe COVID-19

Background Severe disease from COVID-19 was the leading cause of admission to the emergency room and hospitalization during the pandemic in Mexico. Acute kidney injury was one of the most prevalent complications in these patients. The neutrophil/lymphocyte (NL) index and the neutrophil/lymphocyte platelet (NLP) index have previously been described as possible markers associated with complications and mortality in this disease. Objective To determine the association of the NL ratio and the NLP ratio in patients with acute kidney injury secondary to severe COVID-19. Materials and methods This is a case-control study, unpaired, of patients diagnosed with severe COVID-19 who presented or did not present acute kidney injury. On admission to the hospital, the hematological ratios were calculated, and Mann-Whitney U tests and multivariate logistic regression were performed. Results A total of 160 patients were included, and a difference in the NLP ratio (4.2 vs. 3.1, p = 0.001) was observed between patients with and without acute kidney injury. Additionally, the NLP ratio was the main risk variable for acute kidney injury in severe COVID-19, with an odds ratio of 2.5 and a 95% confidence interval of 1.108-5.66. Conclusions The NLP ratio has a moderate association and is a risk factor associated with the presence of acute kidney injury in patients with severe COVID-19.

Kidney Damage in Long COVID: Studies in Experimental Mice

Signs and symptoms involving multiple organ systems which persist for weeks or months to years after the initial SARS-CoV-2 infection (also known as PASC or long COVID) are common complications of individuals with COVID-19. We recently reported pathophysiological changes in various organs post-acute infection of mice with mouse hepatitis virus-1 (MHV-1, a coronavirus) (7 days) and after long-term post-infection (12 months). One of the organs severely affected in this animal model is the kidney, which correlated well with human studies showing kidney injury post-SARS-CoV-2 infection. Our long-term post-infection pathological observation in kidneys includes the development of edema and inflammation of the renal parenchyma, severe acute tubular necrosis, and infiltration of macrophages and lymphocytes, in addition to changes observed in both acute and long-term post-infection, which include tubular epithelial cell degenerative changes, peritubular vessel congestion, proximal and distal tubular necrosis, hemorrhage in the interstitial tissue, and vacuolation of renal tubules. These findings strongly suggest the possible development of renal fibrosis, in particular in the long-term post-infection. Accordingly, we investigated whether the signaling system that is known to initiate the above-mentioned changes in kidneys in other conditions is also activated in long-term post-MHV-1 infection. We found increased TGF-β1, FGF23, NGAL, IL-18, HIF1-α, TLR2, YKL-40, and B2M mRNA levels in long-term post-MHV-1 infection, but not EGFR, TNFR1, BCL3, and WFDC2. However, only neutrophil gelatinase-associated lipocalin (NGAL) increased in acute infection (7 days). Immunoblot studies showed an elevation in protein levels of HIF1-α, TLR-2, and EGFR in long-term post-MHV-1 infection, while KIM-1 and MMP-7 protein levels are increased in acute infection. Treatment with a synthetic peptide, SPIKENET (SPK), which inhibits spike protein binding, reduced NGAL mRNA in acute infection, and decreased TGF-β1, BCL3 mRNA, EGFR, HIF1-α, and TLR-2 protein levels long-term post-MHV-1 infection. These findings suggest that fibrotic events may initiate early in SARS-CoV-2 infection, leading to pronounced kidney fibrosis in long COVID. Targeting these factors therapeutically may prevent acute or long-COVID-associated kidney complications.

Influence of time factor and albuminuria on characteristics of patients with type 2 diabetes Mellitus before, during and 1 year after COVID-19 recovery

BACKGROUND

The potential effects of time factor and albuminuria on the morbid alterations in patients with type 2 diabetes (T2D) and COVID-19 are still unclear. We aimed to address the morbid alterations and the potential effects of time factor and albuminuria on the patients' characteristics before, during, and 1 year after COVID-19 recovery.

METHODS

83 patients with T2D were included, at Mansoura University Hospital, Egypt (July 2021-December 2021). Data of detailed history, physical examination, laboratory tests were recruited from files of the patients. Diagnosis and resolution of COVID-19 were established by Real time polymerase chain reaction (RT-PCR) test of SARS-CoV2. Complete blood count (CBC), renal and hepatic function tests, multiple measures of morning spot urine albumin to creatinine ratio (urine ACR), glycosylated hemoglobin (HBA1c), lipid profile, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Ferritin, neutrophil to lymphocyte ratio (NLR), vitamin D3, intact parathyroid hormone (intact PTH), serum calcium were applied to all participants.

RESULTS

Our participants had a mean age of 45 years, 60.2% male, 56.6% were hospitalized, and 25.3% were admitted to ICU for severe COVID-19. Albuminuria was prevalent in 71.1% before, 98.8% during, and 92.8% after COVID-19 recovery. Patients with albuminuria showed older age, longer duration of T2D, more frequent severe COVID-19 and hospitalization (p = 0.03, p < 0.001, p = 0.023& p = 0.025) respectively. Body mass index (BMI), mean arterial blood pressure, ESR, CRP, ferritin, NLR, HBA1c, triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio, vitamin D3, serum calcium, alkaline phosphatase (ALP), hepatic aminotransferases, and urine ACR showed significant alterations throughout the study (p < 0.001 for all). Although the interaction between time and albuminuria showed non-significant effect on all studied parameters, we noticed relevant main effects of time factor on Body mass index (BMI), HBA1c, glomerular filtration rate (eGFR), TG/HDL ratio, NLR, vitamin D3, (p < 0.001 for all). Moreover, albuminuria showed main effects on BMI, serum creatinine, and intact PTH (p = 0.019, 0.005 & <0.001), respectively.

CONCLUSION

The characteristics of patients with T2D significantly altered throughout the study. Time factor and albuminuria exerted relevant main effects on the patients' characteristics without significant effect of their interaction.

Clinical and subclinical acute kidney injury in children with mild-to-moderate COVID-19

BACKGROUND

Our aim was to identify acute kidney injury (AKI) and subacute kidney injury using both KDIGO criteria and urinary biomarkers in children with mild/moderate COVID-19.

METHODS

This cross-sectional study included 71 children who were hospitalized with a diagnosis of COVID-19 from 3 centers in Istanbul and 75 healthy children. We used a combination of functional (serum creatinine) and damage (NGAL, KIM-1, and IL-18) markers for the definition of AKI and subclinical AKI. Clinical and laboratory features were evaluated as predictors of AKI and subclinical AKI.

RESULTS

Patients had significantly higher levels of urinary biomarkers and urine albumin-creatinine ratio than healthy controls (p < 0.001). Twelve patients (16.9%) developed AKI based on KDIGO criteria, and 22 patients (31%) had subclinical AKI. AKI group had significantly higher values of neutrophil count on admission than both subclinical AKI and non-AKI groups (p < 0.05 for all). Neutrophil count was independently associated with the presence of AKI (p = 0.014).

CONCLUSIONS

This study reveals that even children with a mild or moderate disease course are at risk for AKI. Association between neutrophil count and AKI may point out the role of inflammation in the development of AKI.

IMPACT

The key message of our article is that not only children with severe disease but also children with mild or moderate disease have an increased risk for kidney injury due to COVID-19. Urinary biomarkers enable the diagnosis of a significant number of patients with subclinical AKI in patients without elevation in serum creatinine. Our findings reveal that patients with high neutrophil count may be more prone to develop AKI and should be followed up carefully. We conclude that even children with mild or moderate COVID-19 disease courses should be evaluated for AKI and subclinical AKI, which may improve patient outcomes.

Biochemical and hematological findings and risk factors associated with kidney impairment in patients with COVID-19

Background

COVID-19 is a new pandemic that has infected millions of people worldwide and caused a high morbidity and mortality rate. COVID-19 may have a harmful effect on organs, especially the kidneys. Aims: The main aim of our research is to study the association between the severity of COVID-19 disease and biochemical parameters related to kidney function and to investigate certain risk factors of COVID-19-associated kidney disease.

Methods

A total of 174 individuals, 121 COVID-19 positive and 53 COVID-19 negative, were enrolled in this study. The relation between COVID-19 infection, severity, kidney function test, and hematological indicators were examined.

Results

The most prominent symptoms among COVID-19 were fever (95% ) and fatigue (92%). Regarding biochemical parameters, median creatinine, MPV, and CRP were significantly higher in COVID-19 patients, whereas median eGFR, Na+, WBC, MCH, MCHC, and eosinophil percentages were significantly lower in this group. Severely infected patients were observed to have higher urea, creatinine, neutrophils, and NLR. However, median sodium, eGFR, hemoglobin, hematocrit, RBC, lymphocytes, and platelet count were significantly lower in the severe group. Urine examination of the severe group showed a significantly lower specific gravity, while urine pH, protein, and glucose were significantly higher.

Conclusions

Our analysis indicates that COVID-19 infection affects kidney function, mainly creatinine level, urea, eGFR, Na+ and urine protein. Additionally, comorbidities such as older age (>65), hypertension, taking medications, and CRP (>33.55 mg/L) are considered risk factors that are more likely to contribute to kidney impairment in COVID-19 positive patients.

Subclinical Acute Kidney Injury in COVID-19: Possible Mechanisms and Future Perspectives

Since the outbreak of COVID-19 disease, a bidirectional interaction between kidney disease and the progression of COVID-19 has been demonstrated. Kidney disease is an independent risk factor for mortality of patients with COVID-19 as well as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leading to the development of acute kidney injury (AKI) and chronic kidney disease (CKD) in patients with COVID-19. However, the detection of kidney damage in patients with COVID-19 may not occur until an advanced stage based on the current clinical blood and urinary examinations. Some studies have pointed out the development of subclinical acute kidney injury (subAKI) syndrome with COVID-19. This syndrome is characterized by significant tubule interstitial injury without changes in the estimated glomerular filtration rate. Despite the complexity of the mechanism(s) underlying the development of subAKI, the involvement of changes in the protein endocytosis machinery in proximal tubule (PT) epithelial cells (PTECs) has been proposed. This paper focuses on the data relating to subAKI and COVID-19 and the role of PTECs and their protein endocytosis machinery in its pathogenesis.

Dynamic modulations of urinary sphingolipid and glycerophospholipid levels in COVID-19 and correlations with COVID-19-associated kidney injuries

Background

Among various complications of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), renal complications, namely COVID-19-associated kidney injuries, are related to the mortality of COVID-19.

Methods

In this retrospective cross-sectional study, we measured the sphingolipids and glycerophospholipids, which have been shown to possess potent biological properties, using liquid chromatography-mass spectrometry in 272 urine samples collected longitudinally from 91 COVID-19 subjects and 95 control subjects without infectious diseases, to elucidate the pathogenesis of COVID-19-associated kidney injuries.

Results

The urinary levels of C18:0, C18:1, C22:0, and C24:0 ceramides, sphingosine, dihydrosphingosine, phosphatidylcholine, lysophosphatidylcholine, lysophosphatidic acid, and phosphatidylglycerol decreased, while those of phosphatidylserine, lysophosphatidylserine, phosphatidylethanolamine, and lysophosphatidylethanolamine increased in patients with mild COVID-19, especially during the early phase (day 1–3), suggesting that these modulations might reflect the direct effects of infection with SARS-CoV-2. Generally, the urinary levels of sphingomyelin, ceramides, sphingosine, dihydrosphingosine, dihydrosphingosine l-phosphate, phosphatidylcholine, lysophosphatidic acid, phosphatidylserine, lysophosphatidylserine, phosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylglycerol, lysophosphatidylglycerol, phosphatidylinositol, and lysophosphatidylinositol increased, especially in patients with severe COVID-19 during the later phase, suggesting that their modulations might result from kidney injuries accompanying severe COVID-19.

Conclusions

Considering the biological properties of sphingolipids and glycerophospholipids, an understanding of their urinary modulations in COVID-19 will help us to understand the mechanisms causing COVID-19-associated kidney injuries as well as general acute kidney injuries and may prompt researchers to develop laboratory tests for predicting maximum severity and/or novel reagents to suppress the renal complications of COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00880-5.

Clinical Characteristics and Outcomes of Acute Kidney Injury in Hospitalized Patients with Coronavirus Disease 2019: Experience at a Major Tertiary Care Center in Pakistan

Limited data exist on acute kidney injury (AKI) in patients hospitalized with coronavirus disease 2019 (COVID-19), its risk factors, and the outcomes from lower and middle-income countries. We determined the epidemiology of AKI and its outcomes in a retrospective observational study at a tertiary care center in Karachi, Pakistan, from October to December 2020. Demographic data, presenting clinical symptoms, laboratory results, and patient outcomes were collected from the medical records. AKI was defined according to the Kidney Disease Improving Global Outcomes criteria. Of 301 COVID-19 patients, AKI developed in 188 (62.5%). The peak stages of AKI were Stage 1 in 57%, Stage 2 in 14.9%, and Stage 3 in 27.7%. Of these, 15 (8%) required kidney replacement therapy (KRT). Patients admitted to the intensive care unit (63.8% vs. 34.5%), and those needing vasopressors (31.9% vs. 5.3%) or mechanical ventilation (25% vs. 2.7%) had a higher risk of AKI. Independent predictors of AKI were elevated blood urea nitrogen and creatinine (Cr) at presentation, mechanical ventilation, and the use of anticoagulants. AKI, the presence of proteinuria, elevated serum Cr at presentation, use of vasopressors, and a need for KRT were significantly associated with in-hospital death, and the likelihood of mortality increased with advanced stages of AKI. Compared with other countries, AKI occurred more frequently among hospitalized patients with COVID-19 in this Pakistani cohort and was associated with 7.7-fold higher odds of in-hospital death. Patients with severe AKI had a greater likelihood of mortality than those in earlier stages or without AKI.

Exploring Urinary Extracellular Vesicles and Immune Mediators as Biomarkers of Kidney Injury in COVID-19 Hospitalized Patients

Kidney injury is an important outcome associated with COVID-19 severity. In this regard, alterations in urinary extracellular vesicles (uEVs) could be detected in the early phases of renal injury and may be reflective of the inflammatory process. This is an observational study performed with a case series of COVID-19 hospitalized patients presenting mild-to-critical disease. Total and podocyte-derived uEVs were identified by nanoscale flow cytometry, and urinary immune mediators were assessed by a multiplex assay. We studied 36 patients, where 24 (66.7%) were considered as mild/moderate and 12 (33.3%) as severe/critical. Increased levels of total uEVs were observed (p = 0.0001). Importantly, total uEVs were significantly higher in severe/critical patients who underwent hemodialysis (p = 0.03) and were able to predict this clinical outcome (AUC 0.93, p = 0.02). Severe/critical patients also presented elevated urinary levels (p < 0.05) of IL-1β, IL-4, IL-6, IL-7, IL-16, IL-17A, LIF, CCL-2, CCL-3, CCL-11, CXCL-10, FGFb, M-CSF, and CTAcK. Lastly, we observed that total uEVs were associated with urinary immune mediators. In conclusion, our results show that early alterations in urinary EVs could identify patients at higher risk of developing renal dysfunction in COVID-19. This could also be relevant in different scenarios of systemic and/or infectious disease.

COVID-19 and Kidney Disease: Progress in Health Inequity From Low-Income Settings

The acute coronavirus disease-2019 (COVID-19) pandemic has had a significant impact on the incidence and prevalence of acute kidney injury and chronic kidney disease globally and in low-income settings. Chronic kidney disease increases the risk of developing COVID-19 and COVID-19 causes acute kidney injury directly or indirectly and is associated with high mortality in severe cases. Outcomes of COVID-19-associated kidney disease were not equitable globally owing to a lack of health infrastructure, challenges in diagnostic testing, and management of COVID-19 in low-income settings. COVID-19 also significantly impacted kidney transplant rates and mortality among kidney transplant recipients. Vaccine availability and uptake remains a significant challenge in low- and lower-middle-income countries compared with high-income countries. In this review, we explore the inequities in low- and lower-middle-income countries and highlight the progress made in the prevention, diagnosis, and management of patients with COVID-19 and kidney disease. We recommend further studies into the challenges, lessons learned, and progress made in the diagnosis, management, and treatment of patients with COVID-19-related kidney diseases and suggest ways to improve the care and management of patients with COVID-19 and kidney disease.

The prospective screening for SARS-CoV-2 S1/S2 antibodies delineates the factual incidence of COVID-19 and shows a sustained serological response post COVID-19 in kidney transplant recipients

BACKGROUND

The impact of immunosuppression on the occurrence of Coronavirus Disease 2019 (COVID-19) remains unclear.

METHODS

We conducted a prospective screening of anti-S1/S2 IgGs against SARS-CoV-2 Spike protein from March, 1 2020 to May, 15 2021 (prior to the vaccination campaign) in a cohort of 713 kidney transplant recipients (KTRs). In a first phase, the factual incidence and seroprevalence of COVID-19 was established in this cohort: cases diagnosed by serology were added to RT-PCR-based diagnoses to obtain the overall incidence of COVID-19 in both symptomatic and asymptomatic KTRs. In the second phase, the kinetics of the post-COVID-19 humoral response were studied, taking into account the severity of the disease defined by the need for oxygen therapy (group S, "severe") or not (group nS, "not severe").

RESULTS

The combined diagnostic approaches identified 138 COVID-19 cases (19.2%), with 37 diagnoses by serology (26.8%). The rate of asymptomatic KTRs reached 20.3% (28/138). Thirteen patients (9.4%) died from COVID-19. The seroconversion rate was 91.7% (99/108). The peak anti-S1/S2 IgG level was 85 [30-150] AU/ml and was similar between the S and nS groups (117 [38; 186] AU/ml versus 73 [23; 140] AU/ml). A high probability of persistence of anti-S1/S2 IgG post-COVID-19 was observed, with only 10.1% (7/69) of the patients having negated their serology during the 9-month follow-up.

CONCLUSION

Our pragmatic serological screening combined with RT-PCR tests provides a better estimation of the real incidence of COVID-19 in KTRs. A significant proportion of KTRs develop humoral immunity post COVID-19, which most often persists beyond 9 months.

Urinary tubular biomarkers as predictors of death in critically ill patients with COVID-19

Aim: To evaluate the prediction capacity of urinary biomarkers for death in critically ill patients with COVID-19. Methods: This is a prospective study with critically ill patients due to COVID-19 infection. The urinary biomarkers NGAL, KIM-1, MCP-1 and nephrin were quantified on ICU admission. Results: There was 40% of death. Urinary nephrin and MCP-1 had no association with death. Tubular biomarkers (proteinuria, NGAL and KIM-1) were predictors of death and cut-off values of them for death were useful in stratify patients with worse prognosis. In a multivariate cox regression analysis, only NGAL remains associated with a two-mount survival chance. Conclusion: Kidney tubular biomarkers, mostly urinary NGAL, had useful capacity to predict death in critically ill COVID-19 patients.

The mechanism underlying extrapulmonary complications of the coronavirus disease 2019 and its therapeutic implication

The coronavirus disease 2019 (COVID-19) is a highly transmissible disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that poses a major threat to global public health. Although COVID-19 primarily affects the respiratory system, causing severe pneumonia and acute respiratory distress syndrome in severe cases, it can also result in multiple extrapulmonary complications. The pathogenesis of extrapulmonary damage in patients with COVID-19 is probably multifactorial, involving both the direct effects of SARS-CoV-2 and the indirect mechanisms associated with the host inflammatory response. Recognition of features and pathogenesis of extrapulmonary complications has clinical implications for identifying disease progression and designing therapeutic strategies. This review provides an overview of the extrapulmonary complications of COVID-19 from immunological and pathophysiologic perspectives and focuses on the pathogenesis and potential therapeutic targets for the management of COVID-19.

Urine sediment findings were milder in patients with COVID-19-associated renal injuries than in those with non-COVID-19-associated renal injuries

Background

Acute renal injury is an important complication of coronavirus disease 2019 (COVID-19). Both COVID-19-specific mechanisms, such as damage to the renal parenchyma by direct infection, and non-specific mechanisms, such as the pre-renal injury factors, have been proposed to be involved in COVID-19-associated renal injuries. In this study, we aimed to elucidate the characteristics of COVID-19-associated renal injuries, focusing mainly on urine sediment findings.

Methods

We compared the urine sediment findings and their associations with renal functions or urinary clinical parameters between subjects with COVID-19 and subjects without COVID-19 with acute renal injuries.

Results

We found that the number of urine sediment particles and the levels of N-acetyl-β-D-glucosaminidase, α1-microglobulin, liver type fatty acid-binding protein, and neutrophil gelatinase-associated lipocalin were associated with the severity of COVID-19. In addition, we observed that the number of granular casts, epithelial casts, waxy casts, and urinary chemical marker levels were lower in the subjects with COVID-19 than subjects without COVID-19 with acute renal injuries when the subjects were classified according to their renal function.

Conclusions

These results suggest that pre-renal injury factors might be largely involved in the pathogenesis of COVID-19-associated renal injuries compared with non-COVID-19-associated renal injuries arising from surgery or sepsis.

Using dipstick urinalysis to predict development of acute kidney injury in patients with COVID-19

BACKGROUND

Acute kidney injury (AKI) is a common complication in patients hospitalized with COVID-19 and may require renal replacement therapy (RRT). Dipstick urinalysis is frequently obtained, but data regarding the prognostic value of hematuria and proteinuria for kidney outcomes is scarce.

METHODS

Patients with positive severe acute respiratory syndrome-coronavirus 2 (SARS-CoV2) PCR, who had a urinalysis obtained on admission to one of 20 hospitals, were included. Nested models with degree of hematuria and proteinuria were used to predict AKI and RRT during admission. Presence of Chronic Kidney Disease (CKD) and baseline serum creatinine were added to test improvement in model fit.

RESULTS

Of 5,980 individuals, 829 (13.9%) developed an AKI during admission, and 149 (18.0%) of those with AKI received RRT. Proteinuria and hematuria degrees significantly increased with AKI severity (P < 0.001 for both). Any degree of proteinuria and hematuria was associated with an increased risk of AKI and RRT. In predictive models for AKI, presence of CKD improved the area under the curve (AUC) (95% confidence interval) to 0.73 (0.71, 0.75), P < 0.001, and adding baseline creatinine improved the AUC to 0.85 (0.83, 0.86), P < 0.001, when compared to the base model AUC using only proteinuria and hematuria, AUC = 0.64 (0.62, 0.67). In RRT models, CKD status improved the AUC to 0.78 (0.75, 0.82), P < 0.001, and baseline creatinine improved the AUC to 0.84 (0.80, 0.88), P < 0.001, compared to the base model, AUC = 0.72 (0.68, 0.76). There was no significant improvement in model discrimination when both CKD and baseline serum creatinine were included.

CONCLUSIONS

Proteinuria and hematuria values on dipstick urinalysis can be utilized to predict AKI and RRT in hospitalized patients with COVID-19. We derived formulas using these two readily available values to help prognosticate kidney outcomes in these patients. Furthermore, the incorporation of CKD or baseline creatinine increases the accuracy of these formulas.

Can microalbuminuria be an ındicator of renal ınvolvement in pediatric Covid 19 patients?

Background

Proteinuria (both tubular and glomerular in origin) and its implications are well-known features of adult patients with COVID19. However currently studies addressing proteinuria and its role in the outcome of kidney and patients of pediatric COVID 19 is scarce. We aimed to evaluate the presence of microalbuminuria in order to detect early renal involvement in pediatric COVID 19 patients.

Methods

We prospectively evaluated 100 pediatric patients hospitalized with COVID 19 between April and July 2020. Clinical presentations, laboratory findings and outcomes were investigated. Microalbuminuria was compared with the age, gender, disease severity, and hemoglobin, platelet, leukocyte count and serum CRP levels of the patients.

Results

Twenty seven out of 100 patients had microalbuminuria. Fourteen patients had mild and fourteen had moderate disease. There was not any significant relation according to age and gender. Microalbuminuria was not related to the severity of the disease. Also the mean microalbuminuria level did not differ according to the disease course. Hemoglobin, platelet, leukocyte counts and serum CRP levels were also were not correlated with microalbuminuria levels.

Conclusion

Although there was no difference between the groups with different disease course; microalbuminuria is detected in an important ratio of pediatric patients with COVID 19 in this study. In the highlight of our findings we suggest that urinary findings of pediatric COVID patients should be carefully evaluated.

Evaluation of Tubular Dysfunction Using Urine Biomarkers in Children with COVID-19

OBJECTIVE

The coronavirus disease pandemic is a major problem that the world has been facing since December 2019. It mainly affects the respiratory system; however, the disease can affect the kidneys to different degrees. This study aimed to determine the changes in tubular dysfunction and inflammation parameters in children with coronavirus disease using urine biomarkers.

MATERIALS AND METHODS

We included 36 children who tested positive for severe acute respiratory syndrome coronavirus 2 on real-time reverse transcriptase-polymerase chain reaction using respiratory specimens. Coronavirus disease-positive and -negative period parameters were evaluated. For measurement of interleukin-1β, interleukin-6, and urine β2 microglobulin levels, patients' urine samples were collected at diagnosis and 1 month after discharge. Additionally, routine urine and hematological parameters were evaluated concurrently.

RESULTS

For all patients, the median urine β2 microglobulin, serum urea, and lactate dehydrogenase levels were significantly higher in the coronavirus disease-positive period than in the coronavirus disease-negative period (P < .05). Further, serum platelet count was significantly lower in the coronavirus disease-positive period than in the coronavirus disease-negative period (P < .05). However, there was no difference in serum creatinine, interleukin-6, or interleukin-1β levels between the 2 periods (P > .05).

CONCLUSION

Our results suggest kidney involvement and tubular dysfunction in patients with asymptomatic, mild, and moderate infections. Furthermore, interleukin-1β and interleukin-6 levels were high in the urine, even in non-critically ill patients. We believe that these findings contribute to the accumulation of evidence on continued inflammation in the kidney.

Cardiovascular complications after COVID-19 in chronic kidney disease, dialysis and kidney transplant patients

The coronavirus disease 2019 (COVID-19) is associated with increased mortality in patients with chronic kidney disease (CKD), dialysis patients and kidney transplant recipients (KTR). Cardiovascular complications, such as sudden arrhythmias, thromboembolic events, coronary events, cardiomyopathies and heart failure, may present in about 10–20% of patients with COVID-19. Patients with CKD, dialysis patients and KTR are all at increased cardiovascular risk and present with more cardiovascular complications after COVID-19 compared to the general population. During the pandemic, health care giving has rapidly changed by reducing elective outpatient reviews, which may refrain these high-risk patients from the appropriate management of their medical conditions, further increasing cardiovascular risk. Importantly, acute kidney injury (AKI) is another common complication of severe COVID-19 and associates with increased mortality. A large proportion of the AKI patients need renal replacement treatment, while 30% of them may not present renal function recovery and remain dialysis-dependent after discharge, thereby having potentially increased future cardiovascular risk. This review summarizes current knowledge regarding the cardiovascular events and mortality in patients with CKD or undergoing hemodialysis and in KTR.

Use of Organs from SARS-CoV-2 Infected Donors: Is It Safe? A Contemporary Review

PURPOSE OF REVIEW

As the prevalence of individuals with recovered coronavirus disease 2019 (COVID-19) increases, determining if and when organs from these donors can be safely used is an important priority. We examined current knowledge of outcomes of transplant using donors with recovered COVID-19.

RECENT FINDINGS

A literature search of PubMed and Google scholar databases was conducted to identify articles with terms "SARS-CoV2," "COVID-19," "donor recovered," and "transplantation" published through 08/10/2021. We identified 25 reports detailing 94 recipients of both abdominal and thoracic transplants from donors with both prior and active COVID-19 infection. Rates of transmission to the recipient and of transplanted organ dysfunction were low among reports of donors with prior COVID-19 infection. End organ dysfunction and transmission were more common with active infection, although few reports are available. Standardized reporting is needed to better assess the impact of donor symptomatology, cycle thresholds, and individual recipient risk factors on postoperative outcomes.

SUMMARY

Available reports suggest that transplantation from COVID-19 donors may be feasible and safe, at least in short term follow-up. Nevertheless, there is a need for standardized testing and management protocols which should be tailored for available resources. While increased availability of COVID-19 vaccinations will mitigate risks of donor-derived COVID-19 and simplify management, continued vigilance is warranted during the ongoing public health emergency.

Abnormal Blood Coagulation and Kidney Damage in Aged Hamsters Infected with Severe Acute Respiratory Syndrome Coronavirus 2

Systemic symptoms have often been observed in patients with coronavirus disease 2019 (COVID-19) in addition to pneumonia, however, the details are still unclear due to the lack of an appropriate animal model. In this study, we investigated and compared blood coagulation abnormalities and tissue damage between male Syrian hamsters of 9 (young) and over 36 (aged) weeks old after intranasal infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite similar levels of viral replication and inflammatory responses in the lungs of both age groups, aged but not young hamsters showed significant prolongation of prothrombin time and prominent acute kidney damage. Moreover, aged hamsters demonstrated increased intravascular coagulation time-dependently in the lungs, suggesting that consumption of coagulation factors causes prothrombin time prolongation. Furthermore, proximal urinary tract damage and mesangial matrix expansion were observed in the kidneys of the aged hamsters at early and later disease stages, respectively. Given that the severity and mortality of COVID-19 are higher in elderly human patients, the effect of aging on pathogenesis needs to be understood and should be considered for the selection of animal models. We, thus, propose that the aged hamster is a good small animal model for COVID-19 research.

Frequency and factors associated with proteinuria in COVID-19 patients: a cross-sectional study

Proteinuria is a marker of severity and poor outcome of patients in intensive care unit (ICU). The objective of this study was to determine the frequency of proteinuria and the risk factors associated with proteinuria in Congolese COVID-19 patients. The present cross sectional study of proteinuria status is a post hoc analysis of data from 80 COVID-19 patients admitted at Kinshasa Medical Center (KMC) from March 10th to July 10th, 2020. The population under study came from all adult inpatients (≥18 years old) with a laboratory diagnosis by polymerase chain reaction (PCR) of COVID-19 were selected and divided into two groups (positive proteinuria and negative proteinuria group). Logistic regression models helped to identify the factors associated with proteinuria. The P value significance level was 0.05. Among 80 patients who tested positive for SARS-CoV-2 RT-PCR, 55% had proteinuria. The mean age was 55.2 ± 12.8 years. Fourty-seven patients (58.8%) had history of hypertension and 26 patients (32.5%) diabetes. Multivariable analysis showed age ≥ 65 years (aOR 5,04; 95% CI: 1.51-16.78), diabetes (aOR 3,15; 95% CI: 1.14-8.72), ASAT >40 UI/L (aOR 7,08; 95% CI: 2.40-20.87), ferritin >300 (aOR 13,47; 95% CI: 1.56-26.25) as factors independently associated with proteinuria in COVID-19 patients. Proteinuria is common in Congolese COVID-19 patients and is associated with age, diabetes, ferritin and aspartate aminotransferase (ASAT).

Association of AKI-D with Urinary Findings and Baseline eGFR in Hospitalized COVID-19 Patients

Background

AKI is common in patients hospitalized with coronavirus disease 2019 (COVID-19). Risk factors for AKI requiring dialysis (AKI-D) are not fully understood. We aimed to identify risk factors associated with AKI-D and AKI not requiring dialysis (AKI-ND).

Methods

We reviewed electronic health records of 3186 patients aged ≥18 years old who were hospitalized with COVID-19 across six hospitals. Patient characteristics, urinalysis findings, and inflammatory markers were analyzed for association with in-hospital AKI status (AKI-D, AKI-ND, or no AKI), and we subsequently evaluated mortality.

Results

After adjustment for multiple covariates, higher baseline eGFR was associated with 30% lower odds of AKI-D and 11% lower odds of AKI-ND (for AKI-D, OR, 0.70; 95% CI, 0.64 to 0.77; for AKI-ND, OR, 0.89; 95% CI, 0.85 to 0.92). Patients with obesity and those who were Latino had increased odds of AKI-D, whereas patients with congestive heart failure or diabetes with complications had increased odds of AKI-ND. Females had lower odds of in-hospital AKI (for AKI-D, OR, 0.28; 95% CI, 0.17 to 0.46; for AKI-ND, OR, 0.83; 95% CI, 0.70 to 0.99). After adjustment for covariates and baseline eGFR, 1-4+ protein on initial urinalysis was associated with a nine-fold increase in odds of AKI-D (OR, 9.00; 95% CI, 2.16 to 37.38) and more than two-fold higher odds of AKI-ND (OR, 2.28; 95% CI, 1.66 to 3.13). Findings of 1-3+ blood and trace glucose on initial urinalysis were also associated with increased odds of both AKI-D and AKI-ND. AKI-D and AKI-ND were associated with in-hospital death (for AKI-D, OR, 2.64; 95% CI, 1.13 to 6.17; for AKI-ND, OR, 2.44; 95% CI, 1.77 to 3.35).

Conclusions

Active urine sediments, even after adjustment for baseline kidney function, and reduced baseline eGFR are significantly associated with increased odds of AKI-D and AKI-ND. In-hospital AKI was associated with in-hospital death. These findings may help prognosticate patients hospitalized with COVID-19.

[Kidney damage in COVID-19]

COVID-19 is a disease caused by the RNA virus SARS-CoV-2. It is characterised by an attack mainly affecting the respiratory system. There is renal involvement which is characterised by three main types of damage, acute tubular necrosis occurring in the most severe cases, proximal tubulopathy which is a prognostic marker of the disease and segmental and focal hyalinosis occurring in a genetically predisposed terrain. The pathophysiology of SARS-CoV-2 renal involvement is not yet defined. The direct role of the virus is debated, whereas the cytokine storm and the hypoxic and thrombotic complications seem more important. The long-term outcome of the renal damage appears to be quite good. Long-term follow-up will allow us to say whether the renal damage is part of the long COVID.

Proteinuria in COVID-19

Upper respiratory and pulmonary diseases are the primary manifestations of coronavirus disease 2019 (COVID-19). However, kidney involvement has also been recognized and extensively described. A large percentage of affected patients present with acute kidney injury (AKI). However, specific phenotypic aspects of AKI or other renal manifestations of COVID-19 remain sparsely characterized. Many reports indicate that proteinuria can be detected in AKI associated with COVID-19 (CoV-AKI) despite CoV-AKI being largely described as a form of acute tubular injury. On the other hand, individuals of African ancestry with the high-risk APOL1 genotype are uniquely at risk of developing collapsing glomerulopathy when they are infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the entity now known as COVID-19-associated nephropathy (COVAN). Patients with COVAN typically present with nephrotic-range proteinuria. The exact incidence of proteinuria in COVID-19 is unclear due to heterogeneity in the frequency with which proteinuria has been assessed in cases of COVID-19, as well as methodological differences in the way proteinuria is measured and/or reported. In this review we discuss the current evidence of proteinuria as a manifestation of COVID-19 and elaborate on potential pathophysiological mechanisms associated with it.