Impact of Clinical Aspects and Pathophysiology Mechanisms of Acute Kidney Injury on Outcomes of Patients Affected by COVID-19—A Retrospective Cohort Study

Round 1

Reviewer 1 Report

If the purpose of this article is to determine the association between AKI and death in patients hospitalized with Covid-19, a comparison with a group of patients hospitalized for Covid-19 but not diagnosed with AKI over the same time period is warranted.

 

In addition, it would be desirable to have a factor analysis of prognostic determinants in patients who were diagnosed with AKI but improved to the point of discharge from the hospital.

Graph2

Numbers at risk should be indicated.

It should be indicated whether there is a significant difference between the two groups or not.

Author Response

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Reviewer 2 Report

AKI due to COVID-19 infection is more common in severe cases, but there is a wide variation in the time and cohort in which it is observed. Some reports indicate that the incidence of AKI is also high and has decreased over time in the early cohorts of pandemics, which had a high fatality rate. This study was conducted in the early pandemic period, when many patients presented with respiratory failure, MOF, AKI, and death. Could you indicate which type of COVID-19 was prevalent during the period of this study?

To some extent, there is an etiology-based classification of AKI as inflammatory AKI caused by cytokine storms, MOF, and septic condition, as well as hemodynamic and ischemic AKI caused by dehydration and other factors, and AKI caused by viral tropism. The classification criteria should be clearly stated. Also, how did you classify inflammatory AKI due to cytokine storm, MOF, and septic?　 Furthermore, there is even a Mixed category, and the classification criteria are unclear. These could be grouped together as inflammatory?

Also, how was AKI due to viral tropism diagnosed?　Renal biopsy? 　

Not only tubular damage but also thrombus formation in the peritubular capillary may suggest a pathophysiology characteristic of COVID-19. Can you provide data and discussion on the pathophysiological mechanisms in this area?

Also, proteinuria and hematuria are observed in more than 80% of the cases. Please discuss its mechanism.　Although urinary findings are often considered to be absent in ischemic and hemodynamic etiology.

①    P5　 Figure 1.  Pie charts are usually arranged in order of frequency

②    P8　graph 2.     Figure.2 ?   Hard to see overall

Title: Survival functions？　

Length of stay  　25.00→25 etc

“Associative values”  outside the graph come into the graph.

③    P 4  L159- Is 167 a duplicate?

Author Response

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Reviewer 3 Report

Comments are described below.

My revision is described.

Comments for author File: Comments.pdf

Author Response

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Round 2

Reviewer 2 Report

Many things have been corrected, but some have not yet been reflected.

The response to the following points has not been reflected

 

Also, how was AKI due to viral tropism diagnosed?　Renal biopsy? 　

Not only tubular damage but also thrombus formation in the peritubular capillary may suggest a pathophysiology characteristic of COVID-19. Can you provide data and discussion on the pathophysiological mechanisms in this area?

Also, proteinuria and hematuria are observed in more than 80% of the cases. Please discuss its mechanism.　

It seems that more than 80% of patients with AKI due to viral tropism had proteinuria and hematuria, but direct tubular damage by　COVID-19 virus does not seem to cause hematuria, which is seen in glomerular damage. Please consider whether viral infections are caused by glomerular disease where there was originally glomerular disease.

①      Figure.2 

Not enough. Not clear.

Title is needed.　

Log rank<0.005　→Log rank test: P＜0.005

Length of stay  　25.00 ? →25 etc

Author Response

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Reviewer 3 Report

Although the article was improved, other concerns were included.

The paper still needs be improved in its writing.

Author Response

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Round 3

Reviewer 3 Report

Recommendations were not sucessfully addressed after review. 

My review already was performed.

Author Response

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