COVID-19-related acute kidney injury; incidence, risk factors and outcomes in a large UK cohort

New insights into kidney disease after COVID-19 infection and vaccination: histopathological and clinical findings

In addition to its pulmonary effects, coronavirus disease 2019 (COVID-19) has also been found to cause acute kidney injury (AKI), which has been linked to high mortality rates. In this review, we collected data from 20 clinical studies on post-COVID-19-related AKI and 97 cases of AKI associated with COVID-19 vaccination. Acute tubular injury was by far the most common finding in the kidneys of patients with COVID-19-related AKI. Among patients hospitalized for COVID-19, 34.0% developed AKI, of which 59.0%, 19.1% and 21.9% were Stages 1, 2 and 3, respectively. Though kidney disease and other adverse effects after COVID-19 vaccination overall appear rare, case reports have accumulated suggesting that COVID-19 vaccination may be associated with a risk of subsequent kidney disease. Among the patients with post-vaccination AKI, the most common pathologic findings include crescentic glomerulonephritis (29.9%), acute tubular injury (23.7%), IgA nephropathy (18.6%), antineutrophil cytoplasmic autoantibody-associated vasculitis (17.5%), minimal change disease (17.5%) and thrombotic microangiopathy (10.3%). It is important to note that crescentic glomerulonephritis appears to be more prevalent in patients who have newly diagnosed renal involvement. The proportions of patients with AKI Stages 1, 2 and 3 after COVID-19 vaccination in case reports were 30.9%, 22.7% and 46.4%, respectively. In general, clinical cases of new-onset and recurrent nephropathy with AKI after COVID-19 vaccination have a positive prognosis. In this article, we also explore the underlying pathophysiological mechanisms of AKI associated with COVID-19 infection and its vaccination by describing key renal morphological and clinical features and prognostic findings.

Risk prediction of major cardiac adverse events and all-cause death following covid-19 hospitalization at one year follow-up: The HOPE-2 score

BACKGROUND

Long-term consequences of COVID-19 are still partly known.

AIM OF THE STUDY

To derive a clinical score for risk prediction of long-term major cardiac adverse events (MACE) and all cause death in COVID-19 hospitalized patients.

METHODS

2573 consecutive patients were enrolled in a multicenter, international registry (HOPE-2) from January 2020 to April 2021 and identified as the derivation cohort. Five hundred and twenty-six patients from the Cardio-Covid-Italy registry were considered as external validation cohort. A long-term prognostic risk score for MACE and all cause death was derived from a multivariable regression model.

RESULTS

Out of 2573 patients enrolled in the HOPE-2 registry, 1481 (58 %) were male, with mean age of 60±16 years. At long-term follow-up, the overall rate of patients affected by MACE and/or all cause death was 7.8 %. After multivariable regression analysis, independent predictors of MACE and all cause death were identified. The HOPE-2 prognostic score was therefore calculated by giving: 1-4 points for age class (<65 years, 65-74, 75-84, ≥85), 3 points for history of cardiovascular disease, 1 point for hypertension, 3 points for increased troponin serum levels at admission and 2 points for acute renal failure during hospitalization. Score accuracy at ROC curve analysis was 0.79 (0.74 at external validation). Stratification into 3 risk groups (<3, 3-6, >6 points) classified patients into low, intermediate and high risk. The observed MACE and all-cause death rates were 1.9 %, 9.4 % and 26.3 % for low- intermediate and high-risk patients, respectively (Log-rank test p < 0.01).

CONCLUSIONS

The HOPE-2 prognostic score may be useful for long-term risk stratification in patients with previous COVID-19 hospitalization. High-risk patients may require a strict follow-up.

Burden and risk profile of acute kidney injury in severe COVID-19 pneumonia admissions: a Finding from Jimma University medical center, Ethiopia

BACKGROUND

Acute kidney injury (AKI) is a serious complication of the Corona Virus Disease of 2019 (COVID-19). However, data on its magnitude and risk factors among hospitalized patients in Ethiopia is limited. This study aimed to determine the magnitude of AKI and associated factors among patients admitted for severe COVID-19 pneumonia.

METHODS

An institution-based retrospective cross-sectional study was conducted among 224 patients admitted to Jimma University Medical Center in Ethiopia for severe COVID-19 pneumonia from May 2020 to December 2021. Systematic random sampling was used to select study participants. Medical records were reviewed to extract sociodemographic, clinical, laboratory, therapeutic, and comorbidity data. Bivariable and multivariable logistic regressions were performed to examine factors associated with AKI. The magnitude of the association between the explanatory variables and AKI was estimated using an adjusted odds ratio (AOR) with a 95% confidence interval (CI), and significance was declared at a p-value of 0.05.

RESULTS

The magnitude of AKI was 42% (95% CI: 35.3-48.2%) in the study area. Mechanical ventilation, vasopressors, and antibiotics were required in 32.6, 3.7, and 97.7% of the patients, respectively. After adjusting for possible confounders, male sex (AOR 2.79, 95% CI: 1.3-6.5), fever (AOR 6.5, 95% CI: 2.7-15.6), hypoxemia (AOR 5.1, 95% CI: 1.4-18.9), comorbidities (AOR 2.8, 95% CI: 1.1-7.0), and severe anemia (AOR 10, 95% CI: 1.7-65.7) remained significantly associated with higher odds of AKI.

CONCLUSION

The burden of AKI among patients with severe COVID-19 pneumonia is high in our setting. Male sex, abnormal vital signs, chronic conditions, and anemia can identify individuals at increased risk and require close monitoring and prevention efforts.

Kidney organoids reveal redundancy in viral entry pathways during ACE2-dependent SARS-CoV-2 infection

With a high incidence of acute kidney injury among hospitalized COVID-19 patients, considerable attention has been focussed on whether SARS-CoV-2 specifically targets kidney cells to directly impact renal function, or whether renal damage is primarily an indirect outcome. To date, several studies have utilized kidney organoids to understand the pathogenesis of COVID-19, revealing the ability for SARS-CoV-2 to predominantly infect cells of the proximal tubule (PT), with reduced infectivity following administration of soluble ACE2. However, the immaturity of standard human kidney organoids represents a significant hurdle, leaving the preferred SARS-CoV-2 processing pathway, existence of alternate viral receptors, and the effect of common hypertensive medications on the expression of ACE2 in the context of SARS-CoV-2 exposure incompletely understood. Utilizing a novel kidney organoid model with enhanced PT maturity, genetic- and drug-mediated inhibition of viral entry and processing factors confirmed the requirement for ACE2 for SARS-CoV-2 entry but showed that the virus can utilize dual viral spike protein processing pathways downstream of ACE2 receptor binding. These include TMPRSS- and CTSL/CTSB-mediated non-endosomal and endocytic pathways, with TMPRSS10 likely playing a more significant role in the non-endosomal pathway in renal cells than TMPRSS2. Finally, treatment with the antihypertensive ACE inhibitor, lisinopril, showed negligible impact on receptor expression or susceptibility of renal cells to infection. This study represents the first in-depth characterization of viral entry in stem cell-derived human kidney organoids with enhanced PTs, providing deeper insight into the renal implications of the ongoing COVID-19 pandemic.

IMPORTANCE

Utilizing a human iPSC-derived kidney organoid model with improved proximal tubule (PT) maturity, we identified the mechanism of SARS-CoV-2 entry in renal cells, confirming ACE2 as the sole receptor and revealing redundancy in downstream cell surface TMPRSS- and endocytic Cathepsin-mediated pathways. In addition, these data address the implications of SARS-CoV-2 exposure in the setting of the commonly prescribed ACE-inhibitor, lisinopril, confirming its negligible impact on infection of kidney cells. Taken together, these results provide valuable insight into the mechanism of viral infection in the human kidney.

Outcome Comparison in Hospitalized COVID-19 Patients With and Without AKI

Aim

Patients hospitalized with COVID-19 have a higher incidence of Acute Kidney Injury (AKI) compared with non-COVID patients. Previous observational studies showed AKI in hospitalized patients with COVID-19 was associated with significant increased mortality rate. We conducted a retrospective cohort study in a large mid-Atlantic health system to investigate whether COVID-19 associated AKI during hospitalization would lead to worse outcomes in a predominant Black patient population, compared to COVID-19 without AKI.

Methods

We reviewed health records of patients (aged≥18 years) admitted with symptomatic COVID-19 between March 5, 2020, and Jun 3, 2020, in 9 acute care facilities within the MedStar Health system. Patients were followed up until 3 months after discharge. Primary outcome was inpatient mortality. Secondary outcomes were need for ICU level of care, need for intubation, length of ICU stay, length of hospital stay, need for renal replacement therapy, recovery of renal function.

Results

Among 1107 patients admitted with symptomatic COVID-19, the AKI incidence rate was 35 %. African American patients made up 63 % of the total patient population and 74 % of the total AKI population. Inpatient mortality in the AKI group and the non-AKI group was 163 (41.9 %) and 71 (9.9 %), respectively. COVID-19 patients with AKI had significant higher risk of in-patient mortality (OR, 4.71 [95 % CI, 3.38-6.62], P < 0.001), ICU admission (OR, 4.27 [95 % CI, 3.21-5.72], P < 0.001) and need of intubation (OR, 6.18 [95 % CI, 4.45-8.68], P < 0.001).

Conclusions

AKI in hospitalized patients with COVID-19 was associated with higher mortality rate, need for intubation and ICU admission compared to COVID-19 patients without AKI group.

Potential Alternative Receptors for SARS-CoV-2-Induced Kidney Damage: TLR-4, KIM-1/TIM-1, and CD147

Kidney damage in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur even in patients with no underlying kidney disease. Signs of kidney problems can progress to a state that demands dialysis and hampering recovery. Although not without controversy, emerging evidence implicates direct infectivity of SARS-CoV-2 in the kidney. At the early stage of the pandemic, consideration was mainly on the well-recognized angiotensin-converting enzyme 2 (ACE2) receptor as being the site for viral interaction and subsequent cellular internalization. Despite the abundance of ACE2 receptors in the kidneys, researchers have expanded beyond ACE2 and identified novel viral entry pathways that could be advantageously explored as therapeutic targets. This review presents the potential involvement of toll-like receptor 4 (TLR-4), kidney injury molecule-1/T cell immunoglobulin mucin domain 1 (KIM-1/TIM-1), and cluster of differentiation 147 (CD147) in SARS-CoV-2-associated renal damage. In this context, we address the unresolved issues surrounding SARS-CoV-2 renal infectivity.

Factors associated with acute kidney injury (AKI) and mortality in COVID-19 patients in a Sub-Saharan African intensive care unit: a single-center prospective study

INTRODUCTION

Acute kidney injury (AKI) is a complication of severe coronavirus disease 2019 (COVID-19). Kidney damage associated with COVID-19 could take specific features due to environmental and socio-cultural factors. This study evaluates the incidence of AKI, the associated factors, and mortality in COVID-19 patients in a Sub-Saharan African intensive care unit.

METHODS

In a prospective cohort study conducted in the intensive care unit (ICU) of the Centre Médical de Kinshasa (CMK), consecutive patients admitted for COVID-19 were screened for the presence of AKI between 27 March, 2020 and 27 January 2022. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) guidelines. The primary outcome was occurrence of AKI. The secondary outcome was 48 days' mortality and recovery of the renal function at intensive care unit (ICU) discharge. Survival (time-to death) curves were built using the Kaplan Meier methods. Multivariate analyses were performed by logistic regression to identify factors associated with AKI and Cox regression to explore the association between AKI and in-hospital mortality. The significance level of the p-value was set at 0.05.

RESULTS

The median(IQR) sequential organ failure assessment score (SOFA) score and mean age of patients (215) including in our cohort were respectively 3(2-4) and 58.9 ± 14.9 years. The incidence of AKI was 28.4% with stages 1, 2, or 3 AKI accounted for 39.3%, 11.5%, and 49.2%, respectively. Hemodialysis was required in 16 out 215 (7.4%) patients. Dyspnea (adjusted odds ratio (aOR):2.27 [1.1--4.57] p = 0.021), SOFA ≥5 (aOR:3.11[1.29-7.53] p = 0.012), AST/ALT ratio (aOR: 1.53 [1.09-1.79] p = 0.015), N/L ratio (aOR:2.09 [1.09-3.20] p = 0.016), mechanical ventilation (aOR: 3.20 [1.66-10.51] p = 0.005) and Amikacin (aOR: 2.91 [1.37-6.18] p = 0.006) were the main factors associated with AKI. Patients with AKI had a mortality rate of 52.5% and 67.2% of the survivors did not recover kidney function at the end of hospitalization. Adjusted Cox regression analysis revealed that COVID-19-associated AKI was independently associated with in-hospital death (HR:2.96 [1.93-4.65] p = 0.013) compared to non-AKI patients.

CONCLUSIONS

AKI was present in three out of ten COVID-19 patients. The most significant factors associated with AKI were dyspnea, SOFA ≥ 5, AST/ALT and N/L ratio, mechanical ventilation and Amikacin. AKI has been associated with an almost threefold increase in overall mortality and seven out of ten survivors did not recover kidney function after AKI.

The prognostic value of estimated glomerular filtration rate on admission for death within 30 days among COVID-19 inpatients using fractional polynomial and spline smoothing

BACKGROUND

The common regression models included estimated glomerular filtration rate (eGFR) in the continuous and categorical form for predicting the mortality in COVID-19 inpatients. However, the relationship may be non-linear, and categorizing implies a loss of information. This study aimed to assess the effect of eGFR on admission on death within 30 days among COVID-19 inpatients using flexible and smooth transformations of eGFR and compare the results against the common models.

METHODS

A retrospective study was conducted on hospitalized COVID-19 patients between April 2019 and July 2019 in Hamadan, Western Iran. The effect of eGFR on the death within 30 days was evaluated using different modeling: categorization, linear, unrestricted cubic spline (USC) with 4 knots, and fractional polynomial (FP). The results adjusted for older age and intensive care unit (ICU) admission. Discrimination power and model performance of the best-fitting model was evaluated using the area under the ROC (AUROC) and Brier score.

RESULTS

In total, 2945 patients (median age 61 years; interquartile range 48-73 years) were included, of whom the mortality rate was 9.23%. The relationship between the eGFR and death within 30 days is non-linear, so the degree-2 FP with powers (- 2, - 1) is the best-fitting model. Using the FP model, the risk increased exponentially in eGFR < 45 and then increased linearly and slowly. The AUROC of the FP model involving eGFR, older age, and ICU admission was 0.92 (95% CI 0.90-0.93) with a Brier score of 0.09.

CONCLUSION

There is a non-linear and asymmetric relationship between eGFR and death within 30 days among COVID-19 inpatients. Kidney function can be measured in COCID-19 patients on admission to know better understanding about prognosis of the patients.

Risk factors, clinical characteristics and prognostic value of acute kidney injury in COVID-19 compared with influenza virus and respiratory syncytial virus

BACKGROUND

Acute Kidney Injury (AKI) complicates a substantial part of patients with COVID-19. Direct viral penetration of renal cells through the Angiotensin Converting Enzyme 2 receptor, and indirect damage by the aberrant inflammatory response characteristic of COVID-19 are likely mechanisms. Nevertheless, other common respiratory viruses such as Influenza and Respiratory Syncytial Virus (RSV) are also associated with AKI.

METHODS

We retrospectively compared the incidence, risk factors and outcomes of AKI among patients who were admitted to a tertiary hospital because of infection with COVID-19, influenza (A + B) or RSV.

RESULTS

We collected data of 2593 patients hospitalized with COVID-19, 2041 patients with influenza and 429 with RSV. Patients affected by RSV were older, had more comorbidities and presented with higher rates of AKI at admission and within 7 days (11.7% vs. 13.3% vs. 18% for COVID-19, influenza and RSV, respectively p = 0.001). Nevertheless, patients hospitalized with COVID-19 had higher mortality (18% with COVID-19 vs. 8.6% and 13.5% for influenza and RSV, respectively P < 0.001) and higher need of mechanical ventilation (12.4% vs. 6.5% vs.8.2% for COVID-19, influenza and RSV, respectively, P = 0.002). High ferritin levels and low oxygen saturation were independent risk factors for severe AKI only in the COVID-19 group. AKI in the first 48 h of admission and in the first 7 days of hospitalization were strong independent risk factors for adverse outcome in all groups.

CONCLUSION

Despite many reports of direct kidney injury by SARS-COV-2, AKI was less in patients with COVID-19 compared to influenza and RSV patients. AKI was a prognostic marker for adverse outcome across all viruses.

An observational study on factors associated with ICU mortality in Covid-19 patients and critical review of the literature

The novel pandemic caused by SARS-CoV-2 has been associated with increased burden on healthcare system. Recognizing the variables that independently predict death in COVID-19 is of great importance. The study was carried out prospectively in a single ICU in northern Greece. It was based on the collection of data during clinical practice in 375 adult patients who were tested positive for SARS-CoV-2 between April 2020 and February 2022. All patients were intubated due to acute respiratory insufficiency and received Invasive Mechanical Ventilation. The primary outcome was ICU mortality. Secondary outcomes were 28-day mortality and independent predictors of mortality at 28 days and during ICU hospitalization. For continuous variables with normal distribution, t-test was used for means comparison between two groups and one-way ANOVA for multiple comparisons. When the distribution was not normal, comparisons were performed using the Mann-Whitney test. Comparisons between discrete variables were made using the x² test, whereas the binary logistic regression was employed for the definition of factors affecting survival inside the ICU and after 28 days. Of the total number of patients intubated due to COVID-19 during the study period, 239 (63.7%) were male. Overall, the ICU survival was 49.6%, whereas the 28-day survival reached 46.9%. The survival rates inside the ICU for the four main viral variants were 54.9%, 50.3%, 39.7% and 50% for the Alpha, Beta, Delta and Omicron variants, respectively. Logistic regressions for outcome revealed that the following parameters were independently associated with ICU survival: wave, SOFA @day1, Remdesivir use, AKI, Sepsis, Enteral Insufficiency, Duration of ICU stay and WBC. Similarly, the parameters affecting the 28-days survival were: duration of stay in ICU, SOFA @day1, WBC, Wave, AKI and Enteral Insufficiency. In this observational cohort study of critically ill COVID-19 patients we report an association between mortality and the wave sequence, SOFA score on admission, the use of Remdesivir, presence of AKI, presence of gastrointestinal failure, sepsis and WBC levels. Strengths of this study are the large number of critically ill COVID-19 patients included, and the comparison of the adjusted mortality rates between pandemic waves within a two year-study period.

Furosemide exacerbated the impairment of renal function, oxygenation and medullary damage in a rat model of renal ischemia/reperfusion induced AKI

BACKGROUND

Perioperative acute kidney injury (AKI) caused by ischemia-reperfusion (IR) is a significant contributor to mortality and morbidity after major surgery. Furosemide is commonly used in postoperative patients to promote diuresis and reduce tissue edema. However, the effects of furosemide on renal microcirculation, oxygenation and function are poorly understood during perioperative period following ischemic insult. Herein, we investigated the effects of furosemide in rats subjected IR insult.

METHODS

24 Wistar albino rats were divided into 4 groups, with 6 in each; Sham-operated Control (C), Control + Furosemide (C + F), ischemia/reperfusion (IR), and IR + F. After induction of anesthesia (BL), supra-aortic occlusion was applied to IR and IR + F groups for 45 min followed by ongoing reperfusion for 15 min (T1) and 2 h (T2). Furosemide infusion was initiated simultaneously in the intervention groups after ischemia. Renal blood flow (RBF), vascular resistance (RVR), oxygen delivery (DO_2ren) and consumption (VO_2ren), sodium reabsorption (TNa⁺), oxygen utilization efficiency (VO₂/TNa⁺), cortical (CμO₂) and medullary (MμO₂) microvascular oxygen pressures, urine output (UO) and creatinine clearance (Ccr) were measured. Biomarkers of inflammation, oxidative and nitrosative stress were measured and kidneys were harvested for histological analysis.

RESULTS

IR significantly decreased RBF, mainly by increasing RVR, which was exacerbated in the IR + F group at T2 (2198 ± 879 vs 4233 ± 2636 dyne/s/cm⁵, p = 0.07). CμO₂ (61.6 ± 6.8 vs 86 ± 6.6 mmHg) and MμO₂ (51.1 ± 4.1 vs 68.7 ± 4.9 mmHg, p < 0.05) were both reduced after IR and did not improve by furosemide. Moreover, VO₂/TNa⁺ increased in the IR + F group at T2 with respect to the IR group (IR: 3.3 ± 2 vs IR + F: 8.2 ± 10 p = 0.07) suggesting a possible deterioration of oxygen utilization. Ccr did not change, but plasma creatinine increased significantly in IR + F groups. Histopathology revealed widespread damage both in the cortex and medulla in IR, IR + F and C + F groups.

CONCLUSION

Renal microvascular oxygenation, renal function, renal vascular resistance, oxygen utilization and damage were not improved by furosemide administration after IR insult. Our study suggests that furosemide may cause additional structural and functional impairment to the kidney following ischemic injury and should be used with caution.

Factors Predictive of Development of Acute Kidney Injury in Patients With COVID-19 in Brunei Darussalam

INTRODUCTION

Acute kidney injury (AKI) in coronavirus disease 2019 (COVID-19) patients affects their health outcomes. Incidence and outcomes varied in the literature, particularly with different population and epidemiological demographics. Data remain scarce in the Southeast Asia region. We report the incidence, outcomes, pattern, types of AKI, and factors that influence AKI patient outcomes in Brunei Darussalam.

METHODS

All patients (N = 930) with COVID-19 who were admitted to the National Isolation Center (between 7th August 2021 and 30thSeptember 2021) were included in the study. The confirmation of AKI was based on the KDIGO (Kidney Disease Improving Global Outcomes) criteria.

RESULTS

The mean age of the patients was 41.9 ± 14.4 years with diabetes mellitus (DM), hypertension (HT), and chronic kidney disease (CKD) accounting for 11.7%, 29.1%, and 4.8% of comorbidities, respectively. Overall, 109 (11.7%) had AKI (KDIGO Stage 1 [67.9%], 2 [13.8%], and 3 [18.3%]), while 75.2% of the cases occurred pre-admission and 26.6% were cases of acute exacerbation of CKD. Univariate analysis identified age (odd ratio [OR] 1.06), male gender (OR 1.63), local nationality (OR 8.03), DM (OR 4.44), HT (OR 5.29), vascular disease (OR 6.08), presence of gastrointestinal symptoms (OR 2.08), antibiotic (OR 3.70) and nephrotoxins exposures (OR 8.57) as significant variables. Multivariate analysis showed age (adjusted OR [AOR] 1.04), male gender (AOR 1.67), gastrointestinal symptoms (AOR 1.61), antibiotic (AOR 2.34), and nephrotoxins exposure (AOR 4.73) as significant.

CONCLUSIONS

Our study showed that one in nine patients with COVID-19 developed AKI with almost a third having stages 2 and 3 AKI. Older age, male gender, presence of GI symptoms, and antibiotic and nephrotoxin exposures were significant predictors of AKI. Patients with these factors should be prioritized for admission and treatment. Even though manifestations are generally now less severe, findings from this study can guide the management of COVID-19 as the disease enters the endemic stage. Furthermore, lessons learned from the COVID-19 pandemic will provide useful information and knowledge for future viral outbreaks or pandemics.

Role of increased neutrophil extracellular trap formation on acute kidney injury in COVID-19 patients

Background

A strong association between elevated neutrophil extracellular trap (NET) levels and poor clinical outcomes in patients with coronavirus infection 2019 (COVID-19) has been reported. However, while acute kidney injury (AKI) is a common complication of COVID-19, the role of NETs in COVID-19-associated AKI is unclear. We investigated the association between elevated NETs and AKI and the prognostic role of NETs in COVID-19 patients.

Methods

Two representative markers of NETs, circulating nucleosomes and myeloperoxidase-DNA, were measured in 115 hospitalized patients. Serum levels of interleukin [IL]-6, monocyte chemotactic protein-1 [MCP-1], plasma von Willebrand factor (vWF) and urinary biomarkers of renal tubular damage (β2-microglobulin [β2M] and kidney injury molecule 1 [KIM-1]) were measured.

Results

AKI was found in 43 patients (37.4%), and pre-existing chronic kidney disease (CKD) was a strong risk factor for AKI. Higher circulating NET levels were a significant predictor of increased risk of initial ICU admission, in-hospital mortality (adjusted HR 3.21, 95% CI 1.08–9.19) and AKI (OR 3.67, 95% CI 1.30-10.41), independent of age, diabetes, pre-existing CKD and IL-6 levels. There were strong correlations between circulating nucleosome levels and urinary KIM-1/creatinine (r=0.368, p=0.001) and β2M (r=0.218, p=0.049) levels. NETs were also strongly closely associated with serum vWF (r = 0.356, p&lt;0.001), but not with IL-6 or MCP-1 levels.

Conclusions

Elevated NETs were closely associated with AKI, which was a strong predictor of mortality. The close association between NETs and vWF may suggest a role for NETs in COVID-19-associated vasculopathy leading to AKI.

Acute Kidney Injury Associated with Severe SARS-CoV-2 Infection: Risk Factors for Morbidity and Mortality and a Potential Benefit of Combined Therapy with Tocilizumab and Corticosteroids

Background: Acute kidney injury (AKI) is a common complication in patients with severe COVID-19. Methods: We retrospectively reviewed 249 patients admitted to an intensive care unit (ICU) during the first wave of the pandemic to determine risk factors for AKI. Demographics, comorbidities, and clinical and outcome variables were obtained from electronic medical records. Results: Univariate analysis revealed older age, higher admission serum creatinine, elevated Sequential Organ Failure Assessment (SOFA) score, elevated admission D-Dimer, elevated CRP on day 2, mechanical ventilation, vasopressor requirement, and azithromycin usage as significant risk factors for AKI. Multivariate analysis demonstrated that higher admission creatinine (p = 0.0001, OR = 2.41, 95% CI = 1.56–3.70), vasopressor requirement (p = 0.0001, OR = 3.20, 95% CI = 1.69–5.98), elevated admission D-Dimer (p = 0.008, OR = 1.0001, 95% CI = 1.000–1.001), and elevated C-reactive protein (CRP) on day 2 (p = 0.033, OR = 1.0001, 95% CI = 1.004–1.009) were independent risk factors. Conversely, the combined use of Tocilizumab and corticosteroids was independently associated with reduced AKI risk (p = 0.0009, OR = 0.437, 95% CI = 0.23–0.81). Conclusion: This study confirms the high rate of AKI and associated mortality among COVID-19 patients admitted to ICUs and suggests a role for inflammation and/or coagulopathy in AKI development. One should consider the possibility that early administration of anti-inflammatory agents, as is now routinely conducted in the management of COVID-19-associated acute respiratory distress syndrome, may improve clinical outcomes in patients with AKI.

Long-term interplay between COVID-19 and chronic kidney disease

PURPOSE

The COVID-19 pandemic may have an impact on the long-term kidney function of survivors. The clinical relevance is not clear.

METHODS

This review summarises the currently published data.

RESULTS

There is a bidirectional relationship between chronic kidney disease and COVID-19 disease. Chronic kidney diseases due to primary kidney disease or chronic conditions affecting kidneys increase the susceptibility to COVID-19 infection, the risks for progression and critical COVID-19 disease (with acute or acute-on-chronic kidney damage), and death. Patients who have survived COVID-19 face an increased risk of worse kidney outcomes in the post-acute phase of the disease. Of clinical significance, COVID-19 may predispose surviving patients to chronic kidney disease, independently of clinically apparent acute kidney injury (AKI). The increased risk of post-acute renal dysfunction of COVID-19 patients can be graded according to the severity of the acute infection (non-hospitalised, hospitalised or ICU patients). The burden of chronic kidney disease developing after COVID-19 is currently unknown.

CONCLUSION

Post-acute COVID-19 care should include close attention to kidney function. Future prospective large-scale studies are needed with long and complete follow-up periods, assessing kidney function using novel markers of kidney function/damage, urinalysis and biopsy studies.

COVID-19-associated AKI

PURPOSE OF REVIEW

While it is now widely established acute kidney injury (AKI) is a common and important complication of coronavirus disease (COVID-19) disease, there is marked variability in its reported incidence and outcomes. This narrative review provides a mid-2022 summary of the latest epidemiological evidence on AKI in COVID-19.

RECENT FINDINGS

Large observational studies and meta-analyses report an AKI incidence of 28-34% in all inpatients and 46-77% in intensive care unit (ICU). The incidence of more severe AKI requiring renal replacement therapy (RRT) in ICU appears to have declined over time, in data from England and Wales RRT use declined from 26% at the start of the pandemic to 14% in 2022. The majority of survivors apparently recover their kidney function by hospital discharge; however, these individuals appear to remain at increased risk of future AKI, estimated glomerular filtration rate (eGFR) decline and chronic kidney disease. Importantly even in the absence of overt AKI a significant proportion of survivors of COVID-19 hospitalisation had reduced eGFR on follow-up.

SUMMARY

This review summarises the epidemiology, risk factors, outcomes and treatment of COVID-19-associated AKI across the global pandemic. In particular the long-term impact of COVID-19 disease on kidney health is uncertain and requires further characterisation.

Comparative outcomes for over 100 deceased donor kidney transplants from SARS-CoV-2 positive donors: A single-center experience

Emerging data support the safety of transplantation of extra-pulmonary organs from donors with SARS-CoV-2-detection. Our center offered kidney transplantation (KT) from deceased donors (DD) with SARS-CoV-2 with and without COVID-19 as a cause of death (CoV + COD and CoV+) to consenting candidates. No pre-emptive antiviral therapies were given. We retrospectively compared outcomes to contemporaneous DDKTs with negative SARS-CoV-2 testing (CoVneg). From February 1, 2021 to January 31, 2022, there were 220 adult KTs, including 115 (52%) from 35 CoV+ and 33 CoV + COD donors. Compared to CoVneg and CoV+, CoV + COD were more often DCD (100% vs. 40% and 46%, p < .01) with longer cold ischemia times (25.2 h vs. 22.9 h and 22.2 h, p = .02). At median follow-up of 5.7 months, recipients of CoV+, CoV + COD and CoVneg kidneys had similar rates of delayed graft function (10.3%, 21.8% and 21.9%, p = .16), rejection (5.1%, 0% and 8.5%, p = .07), graft failure (1.7%, 0% and 0%, p = .35), mortality (0.9%, 0% and 3.7%; p = .29), and COVID-19 diagnoses (13.6%, 7.1%, and 15.2%, p = .33). Though follow-up was shorter, CoV + COD was associated with lower but acceptable eGFR on multivariable analysis. KT from DDs at various stages of SARS-CoV-2 infection appears safe and successful. Extended follow-up is required to assess the impact of CoV + COD donors on longer term graft function.

Alterations in the Kynurenine-Tryptophan Pathway and Lipid Dysregulation Are Preserved Features of COVID-19 in Hemodialysis

Coronavirus disease 2019 (COVID-19)-induced metabolic alterations have been proposed as a source for prognostic biomarkers and may harbor potential for therapeutic exploitation. However, the metabolic impact of COVID-19 in hemodialysis (HD), a setting of profound a priori alterations, remains unstudied. To evaluate potential COVID-19 biomarkers in end-stage kidney disease (CKD G5), we analyzed the plasma metabolites in different COVID-19 stages in patients with or without HD. We recruited 18 and 9 asymptomatic and mild, 11 and 11 moderate, 2 and 13 severely affected, and 10 and 6 uninfected HD and non-HD patients, respectively. Plasma samples were taken at the time of diagnosis and/or upon admission to the hospital and analyzed by targeted metabolomics and cytokine/chemokine profiling. Targeted metabolomics confirmed stage-dependent alterations of the metabolome in non-HD patients with COVID-19, which were less pronounced in HD patients. Elevated kynurenine levels and lipid dysregulation, shown by an increase in circulating free fatty acids and a decrease in lysophospholipids, could distinguish patients with moderate COVID-19 from non-infected individuals in both groups. Kynurenine and lipid alterations were also associated with ICAM-1 and IL-15 levels in HD and non-HD patients. Our findings support the kynurenine pathway and plasma lipids as universal biomarkers of moderate and severe COVID-19 independent of kidney function.

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.

COVID-19 Infection in Chronic Kidney Disease Patients in Bulgaria: Risk Factors for Death and Acute Kidney Injury

Regarding COVID-19 infection, Bulgaria has one of the lowest rates of vaccination in Europe, and its COVID-19-related mortality rate has been one of the highest in the European Union. Chronic kidney disease (CKD)-COVID-19 patients are at higher risk of developing acute kidney injury (AKI) and death after hospital admission. This single-center prospective cohort study from Bulgaria included 120 in-patient COVID-19 subjects of whom 70 had CKD and 50 normal renal function. Diabetes mellitus, hypertension, obesity, and cardiovascular disease were statistically more prevalent in the CKD group as compared to the non-CKD group. At admission, D-dimer, creatinine, and urea levels were significantly higher in the CKD group, whereas estimated glomerular-filtration rate was significantly lower as compared to the non-CKD patients. During hospitalization, 23 patients (19.1%) died, of which 19 were in the CKD group (p-value = 0.0096); in addition, 38 developed AKI (31.6%), of which 31 were in the CKD group (p-value = 0.0006). Using binary logistic regression, being male, having experienced AKI, and not having been treated with remdesivir were independent risk factors for COVID-19-induced mortality. Regarding risk of AKI, having had COVID-19-related symptoms for more than 6 days before admission, having CKD at baseline, and having not received remdesivir therapy were independent predictive factors for developing AKI after admission.

COVID-19 and Kidney Disease: A Clinical Perspective

Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome Coronavirus- 2 (SARS-CoV-2), has caused a global pandemic with high morbidity and mortality. The presence of several comorbidities has been associated with a worse prognosis, with chronic kidney disease being a critical risk factor. Regarding COVID-19 complications, other than classical pneumonia and thromboembolism, acute kidney injury (AKI) is highly prevalent and represents a poor prognostic indicator linked to increased disease severity and mortality. Its pathophysiology is multifactorial, revolving around inflammation, endothelial dysfunction, and activation of coagulation, while the direct viral insult of the kidney remains a matter of controversy. Indirectly, COVID-19 AKI may stem from sepsis, volume depletion, and administration of nephrotoxic agents, among others. Several markers have been proposed for the early detection of COVID-19 AKI, including blood and urinary inflammatory and kidney injury biomarkers, while urinary SARS-CoV-2 load may also be an early prognostic sign. Concerning renal replacement therapy (RRT), general principles apply to COVID-19 AKI, but sudden RRT surges may mandate adjustments in resources. Following an episode of COVID-19 AKI, there is a gradual recovery of kidney function, with pre-existing renal impairment and high serum creatinine at discharge being associated with kidney disease progression and long-term dialysis dependence. Finally, kidney transplant recipients represent a special patient category with increased susceptibility to COVID- 19 and subsequent high risk of severe disease progression. Rates of mortality, AKI, and graft rejection are significantly elevated in the presence of COVID-19, highlighting the need for prevention and careful management of the disease in this subgroup.

COVID-19 Variants in Critically Ill Patients: A Comparison of the Delta and Omicron Variant Profiles

BACKGROUND

Coronavirus disease is a pandemic that has disrupted many human lives, threatening people's physical and mental health. Each pandemic wave struck in different ways, infectiveness-wise and mortality-wise. This investigation focuses on critically ill patients affected by the last two variants, Delta and Omicron, and aims to analyse if any difference exists between the two groups.

METHODS

intensive care unit (ICU) COVID-19 consecutive admissions between 1 October 2021 and 31 March 2022 were recorded daily, and data concerning the patients' demographics, variants, main comorbidities, ICU parameters on admission, and the outcome were analysed by a univariate procedure and by a multivariate analysis.

RESULTS

65 patients were enrolled, 31 (47.69%) belonging to the Omicron versus 34 (52.31%) to the Delta group. The mortality rate was 52.94% for the Omicron group versus 41.9% for the Delta group. A univariate analysis showed that the Omicron variant was associated with total comorbidities number, Charlson Comorbidity Index (CCI), pre-existing pulmonary disease, vaccination status, and acute kidney injury (AKI). In stepwise multivariate analysis, the total number of comorbidities was positively associated with the Omicron group, while pulmonary embolism was negatively correlated with the Omicron group.

CONCLUSION

Omicron appears to have lost some of the hallmarks of the Delta variant, such as endothelialitis and more limited cellular tropism when it comes to the patients in the ICU. Further studies are encouraged to explore different therapeutic approaches to treat critical patients with COVID-19.

Mechanisms of SARS-CoV-2 Infection-Induced Kidney Injury: A Literature Review

The severe acute respiratory coronavirus 2 (SARS-CoV-2) has become a life-threatening pandemic. Clinical evidence suggests that kidney involvement is common and might lead to mild proteinuria and even advanced acute kidney injury (AKI). Moreover, AKI caused by coronavirus disease 2019 (COVID-19) has been reported in several countries and regions, resulting in high patient mortality. COVID-19-induced kidney injury is affected by several factors including direct kidney injury mediated by the combination of virus and angiotensin-converting enzyme 2, immune response dysregulation, cytokine storm driven by SARS-CoV-2 infection, organ interactions, hypercoagulable state, and endothelial dysfunction. In this review, we summarized the mechanism of AKI caused by SARS-CoV-2 infection through literature search and analysis.

Comparison of Two Waves of COVID-19 in Critically Ill Patients: A Retrospective Observational Study

Background

The SARS-CoV-2 virus caused the global COVID-19 pandemic, with waxing and waning course. This study was conducted to compare outcomes in the first two waves, in mechanically ventilated patients.

Methods

This retrospective observational study included all mechanically ventilated COVID-19 patients above 18 years of age, between March 2020 and January 2021. Patients were grouped into first wave from March 2020 to July 2020, and second wave from August 2020 to January 2021. Outcome measures were mortality, the development of acute kidney injury (AKI), and need for renal replacement therapy (RRT). Univariate and multivariate cox regression analysis were used to delineate risk factors for the outcome measures.

Results

A total of 426 patients, 285 in the first wave and 185 in the second wave, were included. The incidence of AKI was significantly lower in the second wave (72% vs. 63%; p=0.04). There was no significant difference in mortality (70% vs. 63%; p=0.16) and need for RRT (36% vs. 30%; p=0.1). Risk factors for mortality were increasing age and AKI in both waves, and chronic kidney disease (CKD) (adj. HR 1.7; 95% CI 1.02-2.68; p=0.04) in the second wave. Risk factors for AKI were CKD in both the waves, while it was diabetes (adj. HR 1.4; 95% CI 1.02-1.95; p=0.04) and increasing age in the first wave. Remdesivir (adj. HR 0.5; 95% CI 0.3-0.7; p < 0.01) decreased the risk of AKI, and convalescent plasma (adj. HR 0.5; 95% CI 0.3-0.9; p=0.02) decreased the risk of mortality in the first wave, however, such benefit was not observed in the second wave.

Conclusions

Our study shows a decrease in the incidence of AKI in critically ill patients, however, the reason for this decrease is still unknown. Studies comparing the waves of the pandemic would not only help in understanding disease evolution but also to develop tailored management strategies.

Complement Activation via the Lectin and Alternative Pathway in Patients With Severe COVID-19

Complement plays an important role in the direct defense to pathogens, but can also activate immune cells and the release of pro-inflammatory cytokines. However, in critically ill patients with COVID-19 the immune system is inadequately activated leading to severe acute respiratory syndrome (SARS) and acute kidney injury, which is associated with higher mortality. Therefore, we characterized local complement deposition as a sign of activation in both lungs and kidneys from patients with severe COVID-19. Using immunohistochemistry we investigated deposition of complement factors C1q, MASP-2, factor D (CFD), C3c, C3d and C5b-9 as well as myeloperoxidase (MPO) positive neutrophils and SARS-CoV-2 virus particles in lungs and kidneys from 38 patients who died from COVID-19. In addition, tissue damage was analyzed using semi-quantitative scores followed by correlation with complement deposition. Autopsy material from non-COVID patients who died from cardiovascular causes, cerebral hemorrhage and pulmonary embolism served as control (n=8). Lung injury in samples from COVID-19 patients was significantly more pronounced compared to controls with formation of hyaline membranes, thrombi and edema. In addition, in the kidney tubular injury was higher in these patients and correlated with lung injury (r=0.361*). In autopsy samples SARS-CoV-2 spike protein was detected in 22% of the lungs of COVID-19 patients but was lacking in kidneys. Complement activation was significantly stronger in lung samples from patients with COVID-19 via the lectin and alternative pathway as indicated by deposition of MASP-2, CFD, C3d and C5b9. Deposits in the lung were predominantly detected along the alveolar septa, the hyaline membranes and in the alveolar lumina. In the kidney, complement was significantly more deposited in patients with COVID-19 in peritubular capillaries and tubular basement membranes. Renal COVID-19-induced complement activation occurred via the lectin pathway, while activation of the alternative pathway was similar in both groups. Furthermore, MPO-positive neutrophils were found in significantly higher numbers in lungs and kidneys of COVID-19 patients and correlated with local MASP-2 deposition. In conclusion, in patients who died from SARS-CoV-2 infection complement was activated in both lungs and kidneys indicating that complement might be involved in systemic worsening of the inflammatory response. Complement inhibition might thus be a promising treatment option to prevent deregulated activation and subsequent collateral tissue injury in COVID-19.

Correction to: COVID-19-related acute kidney injury; incidence, risk factors and outcomes in a large UK cohort

An amendment to this paper has been published and can be accessed via the original article.