Acute kidney injury associated with COVID-19: A retrospective cohort study

Nitin V. Kolhe , Richard J. Fluck, Nicholas M. Selby, Maarten W. Taal


Initial reports indicate a high incidence of acute kidney injury (AKI) in Coronavirus Disease 2019 (COVID-19), but more data are required to clarify if COVID-19 is an independent risk factor for AKI and how COVID-19–associated AKI may differ from AKI due to other causes. We therefore sought to study the relationship between COVID-19, AKI, and outcomes in a retrospective cohort of patients admitted to 2 acute hospitals in Derby, United Kingdom.


The rapid progression of the global pandemic caused by the novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has resulted in an urgent need to understand the pathogenesis and variable clinical features of Coronavirus Disease 2019 (COVID-19). Lung involvement in the form of viral pneumonia, inflammatory infiltrates, and endothelial damage resulting in respiratory failure has been well documented and has been the focus of attention, but other organs including the kidneys are also affected in COVID-19. In the previous SARS epidemic, the reported incidence of acute kidney injury (AKI) was 6.7% with a high mortality of over 90%. However, SARS-CoV-2 is a novel betacoronavirus belonging to the sarbecovirus subgenus of Coronaviridae family, and its effect on the kidneys is not yet fully understood.


Study design and ethical approval

This was an investigator-initiated, multicentre, retrospective cohort study. The study protocol was assessed by the Research and Development Department of University Hospitals of Derby and Burton (UHDB) National Health Service (NHS) Trust and approved by the Health Research Authority and Wales Research Ethics Committee, and the study was registered in the National Library of Medicine website ( with registration number NCT04407156. The protocol is available as S1 Text. The research involved analysis of anonymised data routinely collected in the course of normal care and written informed consent was waived due to the nature of the study and pandemic nature of the disease. Data were analysed and interpreted by the authors who reviewed the manuscript and confirm the accuracy and completeness of the data and adherence to the protocol. The study was conducted according to the principles expressed in the Declaration of Helsinki, and the results are reported according to the strengthening the reporting of observational studies in epidemiology (STROBE) guidelines (S1 Checklist).


During the period from 5 March 2020 to 12 May 2020, 4,759 patients, who were tested for COVID-19, had 5,932 admissions to the UHDB. We excluded the following as per the exclusion criteria: 261 patients under the age of 18 years, 32 admissions in 21 patients on various forms of maintenance dialysis, and 4 duplicate records. There were 1,100 initial admissions with subsequent readmissions during the study period. In the final analysis, we included 4,535 admissions in 4,535 patients, of whom 1,161 were SARS-CoV-2 PCR–positive and 3,374 were SARS-CoV-2 PCR–negative. Data on comorbidities were missing in 14 patients, and ethnicity was missing in 7 patients.


In this retrospective, multicentre study, we found a high incidence of AKI affecting more than a quarter of hospitalised patients with COVID-19. Independent predictors of AKI included age, CCF, CKD, and chronic liver disease along with mechanical ventilation. The impact of AKI on outcomes in the context of COVID-19 was demonstrated by the finding that AKI was independently associated with 3-fold higher odds of death. Furthermore, by comparing AKI in patients with and without COVID-19, we observed that AKI associated with COVID-19 was independently associated with almost 4-fold higher odds of death than AKI associated with other acute illnesses.


The authors gratefully acknowledge the information and technology support provided by Simon Randle from the University Hospitals of Derby and Burton.

Citation: Kolhe NV, Fluck RJ, Selby NM, Taal MW (2020) Acute kidney injury associated with COVID-19: A retrospective cohort study. PLoS Med 17(10): e1003406.

Editor: Giuseppe Remuzzi, Istituto Di Ricerche Farmacologiche Mario Negri, ITALY

Received: June 17, 2020; Accepted: September 29, 2020; Published: October 30, 2020

Copyright: © 2020 Kolhe et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: The authors received no specific funding for this work.

Competing interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: MWT is a member of the Editorial Board of PLOS Medicine NVK, RJF & NMS have declared that no competing interests exist.

Abbreviations: ACEI, angiotensin converting enzyme inhibitors; ACE2, angiotensin converting enzyme 2; AKI, acute kidney injury; ARB, angiotensin receptor blocker; CCF, congestive cardiac failure; CCMD, critical care minimum dataset; CCI, Charlson comorbidity index; CI, confidence interval; CKD, chronic kidney disease; COVID-19, Coronavirus Disease 2019; CRRT, continuous renal replacement therapy; CTD, connective tissue disorder; CVD, cerebrovascular disease; EPMA, electronic prescribing and medicine administration; EPR, electronic patient record; HR, hazard ratio; h-AKI, hospital-acquired AKI; ICD-10-CM, International Classification of Diseases, 10th Revision, Clinical Modification; ICNARC, Intensive Care National Audit and Research Centre; ICU, intensive care unit; IT, information technology; KDIGO, Kidney Disease Improving Global Outcomes; LIMS, laboratory information management system; MI, myocardial infarction; NHS, National Health Service; OR, odds ratio; PVD, peripheral vascular disease; RRT, renal replacement therapy; RT-PCR, real-time reverse transcriptase polymerase chain reaction; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; SD, standard deviation; SLED, slow low efficiency dialysis; UHDB, University Hospitals of Derby and Burton.

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