key: cord-313402-f3indt3b
authors: Hong, X.-w.; Chi, Z.-p.; Liu, G.-y.; Huang, H.; Guo, S.-q.; Fan, J.-r.; Lin, X.-w.; Qu, L.-z.; Chen, R.-l.; Wu, L.-j.; Wang, L.-y.; Zhang, Q.-c.; Wu, S.-w.; Pan, Z.-q.; Lin, H.; Zhou, Y.-h.; Zhang, Y.-h.
title: Analysis of early renal injury in COVID-19 and diagnostic value of multi-index combined detection
date: 2020-03-10
journal: nan
DOI: 10.1101/2020.03.07.20032599
sha: 
doc_id: 313402
cord_uid: f3indt3b

Objectives The aim of the study was to analyze the incidence of COVID-19 with early renal injury, and to explore the value of multi-index combined detection in diagnosis of early renal injury in COVID-19. Design The study was an observational, descriptive study. Setting This study was carried out in a tertiary hospital in Guangdong, China. Participants 12 patients diagnosed with COVID-19 from January 20, 2020 to February 20, 2020. Primary and secondary outcome measures The primary outcome was to evaluate the incidence of early renal injury in COVID-19. In this study, the estimated glomerular filtration rate (eGFR), endogenous creatinine clearance (Ccr) and urine microalbumin / urinary creatinine ratio (UACR) were calculated to assess the incidence of early renal injury. Secondary outcomes were the diagnostic value of urine microalbumin (UMA), 1-microglobulin (A1M), urine immunoglobulin-G (IGU), urine transferring (TRU) alone and in combination in diagnosis of COVID-19 with early renal injury. Results While all patients had no significant abnormalities in serum creatinine (Scr) and blood urea nitrogen (BUN), the abnormal rates of eGFR, Ccr, and UACR were 66.7%, 41.7%, and 41.7%, respectively. Urinary microprotein detection indicated that the area under curve (AUC) of multi-index combined to diagnose early renal injury in COVID-19 was 0.875, which was higher than UMA (0,813), A1M (0.813), IGU (0.750) and TRU (0.750) alone. Spearman analysis showed that the degree of early renal injury was significantly related to C-reactive protein (CRP) and neutrophil ratio (NER), suggesting that the more severe the infection, the more obvious the early renal injury. Hypokalemia and hyponatremia were common in patients with COVID-19, and there was a correlation with the degree of renal injury. Conclusions Early renal injury was common in patients with COVID-19. Combined detection of UMA, A1M, IGU, and TRU was helpful for the diagnosis of early renal injury in COVID-19.

This study intends to use a number of laboratory test indexes, including serum creatinine, blood urea nitrogen, urine creatinine, urine microalbumin and urine microglobulin et al to comprehensively assess renal function and determine the incidence of COVID-19 with early renal injury. The related risk factors of COVID-19 with early renal injury were also analyzed. 

A standardized case collection form was designed to collect laboratory data of the included patients. It mainly included the following items: (1) blood routine; (2) biochemical indexes of kidney, liver, and heart function; (3) coagulation function; (5) infection indexes.

Serum creatinine (Scr), blood urea nitrogen (BUN), urine creatinine (Ucr), urine protein (PRO), urine microalbumin (UMA), α 1-microglobulin (A1M), urine immunoglobulin G (IGU), and urine transferrin (TRU) were detected. The estimated glomerular filtration rate (eGFR), endogenous creatinine clearance (Ccr), and urine microalbumin/creatinine ratio (UACR) were calculated.

All rights reserved. No reuse allowed without permission.

author/funder, who has granted medRxiv a license to display the preprint in perpetuity. In this study, two or more abnormalities of eGFR, Ccr and UACR were defined as early renal injury.

The area under curves (AUC) of receiver operating characteristic (ROC) were calculated for predictive analysis. Spearman rank correlation coefficient was used to analyze the linear correlation between two sets of continuous variables. It was considered statistically significant when the P value was less than 0.05. All statistical analyses were processed using SPSS 25.0 statistical software.

Patients were not directly involved in the design, planning and conducting of this study.

Of the 12 patients with COVID-19, 2 were severe patients, 8 were general patients, and 2 were light patients. Laboratory testing items included blood routine, electrolyte, metabolism, heart, liver, kidney function indicators, coagulation function and infection indicators. As shown in Table 1 , the common abnormal indicators (abnormal rate ≥ 50%) included: increased neutrophil ratio (50%), increased monocyte ratio All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint (75%), hypokalemia (50%), hyponatremia (50%), hypoproteinemia (75%), and increased C-reactive protein (83.3%).

As shown in Table 2 , Scr and BUN were not significantly abnormal in 12 patients.

However, the calculation of eGFR and Ccr showed that early renal injury was common in COVID-19 patients. Among them, 66.7% patients had reduced eGFR and 41.7% patients had reduced Ccr. Urinary microprotein test also confirmed that COVID-19 with early renal injury was common, with UACR> 30mg / g accounting for 41.7%. Among the 12 patients, the abnormally elevated rates of UMA, A1M, IGU, and TRU were 33.3%, 33.3%, 41.7%, and 16.7%, respectively. The positive rate of the four-index combined was 58.3%. The results suggested that case 3, 5, 6, and 7 were significant early kidney injury cases.

The AUC of UMA, A1M, IGU, and TRU for the diagnosis of early renal injury in COVID-19 were 0.813, 0.813, 0.750, and 0.750 respectively, while the AUC of the combined index of UMA + A1M + IGU + TRU was 0.875, suggesting that the multi-index combined was helpful for the diagnosis of early renal injury in COVID-19, as shown in Fig 1. 

In this study, Spearman correlation coefficients were used to evaluate the correlation between renal function indicators (eGFR, Ccr, and UACR) and the obviously abnormal biochemical indicators (C-reactive protein (CRP), neutrophil ratio (NER), monocyte ratio (MOR), serum potassium (K), serum sodium (Na), and albumin (ALB)). As shown in Table 3 , it was found that eGFR was negatively correlated with CRP and NER, and positively correlated with serum K, Ccr was negatively correlated All rights reserved. No reuse allowed without permission.

author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint with CRP and NER, and positively correlated with MOR and serum Na, and UACR was positively correlated with CRP, and negatively correlated with serum K (Fig 2) .

The results suggested that the more severe the infection, the more obvious the early renal injury, and the early renal injury in COVID-19 can often cause hypokalemia and hyponatremia.

Coronaviruses are single-stranded positive-strand RNA viruses. In 2014, the Peng Zhou et al [11] reported the identification and characterization of 2019-nCoV. Through full-length genome sequences analysis, they found that the whole genome of 2019-nCoV shared 79.5% sequence identify to SARS-CoV. The pairwise protein sequence analysis of seven conserved non-structural proteins showed that this virus belongs to the species of severe acute respirator syndrome-related All rights reserved. No reuse allowed without permission.

author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint coronaviruses (SARSr-CoV). In addition, they also confirmed that 2019-nCov used the same cell entry receptor, Angiotensin converting enzyme II (ACE2), as SARS-CoV. The high degree of similarity in gene sequence and cellular mechanism of 2019-nCoV and SARS-CoV suggests that the risk factors of mortality could also be similar. SARS is an acute respiratory infectious disease with pulmonary parenchyma and/or interstitium as the main site of invasion and multiple organ injury. Previous clinical studies have found that, similar to SARS, the causes of death caused by 2019-nCov are not only lung tissue damage, but also heart, liver, kidney and other organ dysfunction or even failure, which is one of the important causes of aggravation and death. [8, 9] In the previous SARS case study [12] , acute renal injury was found to be the top risk factor of mortality, even higher than acute respiratory distress. In that case study, all patients who eventually died had a progressive rise of Scr, and the rise of Scr was rapid in those who succumbed early in their illness. Previously, an ongoing case study reported 59 patients infected by 2019-nCoV, including 28 severe cases and 3 death. In that study, 63% of the patients exhibited proteinuria, and 19% and 27% of the patients had an elevated level of Scr and BUN respectively. Computed tomography (CT) scans revealed abnormal renal imaging in all patients. The results suggested that renal injury was common in COVID-19, which may contribute to multiorgan failure and death eventually. [13] In this study, 12 COVID-19 cases were analyzed. Although all the patients still had normal level of Scr and BUN, the high incidence of early renal injury in COVID-19 was found by calculating eGFR, CCR and UACR. The abnormal rates of eGFR, Ccr, and UACR were 66.7%, 41.7%, and 41.7%, respectively. Combined detection of UMA, A1M, IGU, and TRU could be helpful for the diagnosis of early renal injury in COVID-19. Furthermore, the study also found that the degree of early renal injury was significantly related to C-reactive protein (CRP) and neutrophil ratio (NER), suggesting that the more severe the infection, the more obvious the early renal injury. Hypokalemia and hyponatremia were common in patients with COVID-19, and there was a correlation with the degree of renal injury. Xin Zou et al [14] analyzed All rights reserved. No reuse allowed without permission.

author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint the single-cell RNA sequencing datasets to explore the expression of ACE2 in the main physiological systems of the human body, including the respiratory, cardiovascular, digestive and urinary system. The study showed that heart, esophagus, kidney, bladder, and ileum have similar or higher ACE2 expression than in alveoli. In the analysis of specific cell types, the expression of ACE2 in renal proximal tubule cells was about four times higher than that of type II alveolar cells (AT2). The results suggest that the kidney may be one of the primary targets of attack for the 2019-nCov. α 1-microglobulin can pass through the glomerular filtration membrane, and 95% to 99% is reabsorbed in the proximal tubule, and it is not affected by pH. In the early stage of renal injury, the renal tubule reabsorption function reduced, resulting in urine α 1-microglobulin excretion increased, and the elevation is consistent with the degree of renal tubular injury.

[16] Due to the large molecular weight, immunoglobulin G is All rights reserved. No reuse allowed without permission.

author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint difficult to pass through the glomerular filtration membrane. When renal function is impaired, it can lead to increased permeability of the glomerular filtration membrane.

The excretion of albumin in urine increases, and as the lesions worsen, the excretion of immunoglobulin G in urine also increases. Therefore, the detection of urine immunoglobulin G can help to judge the degree of damage on the glomerular filtration membrane.

[17] The main physiological function of transferrin is to transport iron ions. It is a negatively charged protein, and its isoelectric point is one unit higher than that of albumin. Normally, it cannot pass through the positively charged glomerular filtration membrane. Urine transferrin is one of the indicators of early glomerular injury, which mainly reflects the damage of glomerular filtration membrane charge selection barrier. [18] 

Strengths of this study are as follows: Firstly, this study first investigated the incidence of early renal injury in COVID-19 and revealed the prevalence of early renal injury in COVID-19 patients. Secondly, this study clarified the value of multi-index combined detection for the diagnosis of early renal injury in COVID-19, and provided a basis for early detection and early intervention. The present study has some limitations that must be taken into account when considering its contribution.

First and most significantly is the small sample size of this study. COVID-19 is a newly emerging epidemic. The cases found in this city are all imported cases. After strict prevention and control, there are fewer confirmed cases in this city. Therefore, the number of cases included in this research is also small. In addition, considering COVID-19 is a completely new disease, and we do not yet fully know the characteristics of its cases, the type of research used in this study is designed as a descriptive study, which initially explores the basic characteristics of the disease and does not set the control group.

This study found that early renal injury was common in patients with COVID-19.

Combined detection of UMA, A1M, IGU, and TRU could be helpful for the diagnosis All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint of early renal injury in COVID-19. The 12 cases of COVID-19 reported in this study were all healed and discharged after being treated with antivirals, maintaining water and electrolyte balance, enhancing immunity, oxygen therapy, and traditional chinses medicine treatment. In the process of diagnosis and treatment, the assessment of early author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.07.20032599 doi: medRxiv preprint Legend Table 1. Laboratory test results of the COVID-19 patients   Table 2 . Renal function indexes of the COVID-19 patients Table 3 . Laboratory indexes related to early renal injury in COVID-19 author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the . author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint (which was not peer-reviewed) is the 

Clinical features of patients infected with 2019 novel coronavirus in Wuhan

Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study

Coronaviruses -drug discovery and therapeutic options

A pneumonia outbreak associated with a new coronavirus of probable bat origin

Acute renal impairment in coronavirus-associated severe acute respiratory syndrome

(eGFR: estimated glomerular filtration rate; Ccr: endogenous creatinine clearance; UACR: urine microalbumin/creatinine ratio