key: cord-0820611-dlao3plx
authors: Favà, A; Cucchiari, D; Montero, N; Toapanta, N; Centellas, J; Vila‐Santandreu, A; Coloma, A; Meneghini, M; Manonelles, A; Sellarés, J; Torres, I; Gelpi, R; Lorenzo, I; Ventura‐Aguiar, P; Cofan, F; Torregrosa, V; Perelló, M; Facundo, C; Seron, D; Oppenheimer, F; Bestard, O; Cruzado, JM; Moreso, F; Melilli, E
title: Clinical characteristics and risk factors for severe COVID‐19 in hospitalized kidney transplant recipients: A multicentric cohort study
date: 2020-08-10
journal: Am J Transplant
DOI: 10.1111/ajt.16246
sha: cb67357fc5b648bbd733d988cf71a410815b8286
doc_id: 820611
cord_uid: dlao3plx

Kidney transplant recipients might be at higher risk for severe coronavirus disease 2019 (COVID‐19). However, risk factors for relevant outcomes remain uncertain in this population. This is a multicentric kidney transplant cohort including 104 hospitalized patients between Mar 4 and Apr 17, 2020. Risk factors for death and acute respiratory distress syndrome (ARDS) were investigated, and clinical and laboratory data was analyzed. The mean age was 60 years. Forty‐seven patients (54.8%) developed ARDS. Obesity was associated to ARDS development (OR 2.63; p=0.04). Significant age differences were not found among patients developing and not developing ARDS (61.3yr vs 57.8yr, p=0.16). Seventy‐six (73%) patients were discharged while 28 (27%) died. Death was more common among the elderly (55yr and 70.8yr, p<0.001) and those with preexisting pulmonary disease (OR 2.89 , p=0.009). At admission, higher baseline lactate dehydrogenase (257 IU/ml vs 358 IU/ml, p=0.001) or ARDS conferred higher risk of death (HR 2.09, p=0.044). In our cohort, ARDS was equally present among young and old kidney recipients. However, the elderly might be at higher risk of death, along with those showing higher baseline LDH at admission.

In December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) emerged in China, which was shortly recognized as the pathogen of a new cluster of respiratory illness designated as coronavirus infectious disease 2019 (COVID-19) 1 .

Clinical course and prognosis of COVID-19 have been thoroughly described, identifying older age and the presence of comorbidities as the main risk factors for mortality and acute respiratory distress syndrome (ARDS) development [2] [3] [4] 

This is a retrospective multicentric observational cohort study. Our study enrolled all KT recipients with COVID-19 infection and hospitalized between 4th March and 17th April 2020 in participant centers. All of them had confirmed SARS-CoV-2 infection by real time reverse transcriptase-polymerase reaction (rt-PCR) analysis performed on nasal or pharyngeal swab samples. The hospital admission criteria were: need of oxygen therapy, X-Ray infiltrates, renal dysfunction, or those with recent (< 7 days) symptoms onset regardless of its severity (i.e. fever without pneumonia or diarrhea). All patients included had a complete follow-up until discharge (curation or clinical improvement) or death. COVID-19 kidney transplant recipients with exclusively outpatient care were excluded from the analysis because of the potential notreported cases and the lack of follow-up data. Data was obtained and recorded in a common data collection form in all transplant centers. The study was approved by all Hospital Ethical Review Boards (PR173/20).

We collected the following baseline data: age, race/ethnicity, gender, time after KT, first or retransplantation, type of transplant (kidney or combined pancreas with kidney or liver with kidney), type of donor (deceased or living), primary end stage renal disease (ESRD), maintenance immunosuppression, induction therapy, basal graft function (serum creatinine and estimated glomerular filtration rate by CKD-EPI (eGFR)), comorbidities such as heart disease (heart failure, coronary artery disease, atrial fibrillation or valvular heart disease), hypertension (type of treatment before illness), obesity (body mass index ≥ 30), pulmonary disease (chronic obstructive pulmonary disease, bronchiectasis, asthma or sleep apneahypopnea syndrome), active neoplasm, or lymphopenia before admission. Initial clinical symptoms (fever defined by a temperature > 37.5ºC, respiratory status recorded through the pulse oximetry saturation/fraction of inspired oxygen ratio (SpO2/FiO2)) and also X-ray evaluation and analytical assessment that was carried out at admission, 3, 6, 9, 12, and 15 days after the admission were also recorded. Individuals considered to have a COVID-19 nosocomial infection were patients in these two clinical scenarios: a diagnosis of COVID-19 while being hospitalized due to a different clinical reason or COVID-19 infection in patients who had been discharged from the hospital within the preceding 14 days. Missing data was recovered and inconsistencies were corrected through online interaction.

The primary endpoints were death and acute respiratory disease syndrome (ARDS) defined by the World Health Organization interim guidance (bilateral opacities not explained by volume overload and SpO2/FiO2 ratio <315) 10 . The secondary endpoints were acute kidney injury (AKI) Accepted Article using KDIGO definition 11 , number and type of immunosuppression withdrawal, use of anti-COVID-19 therapies, and associated adverse events (including gastrointestinal, cutaneous rash, QT prolongation (considered prolonged if QTc values are greater than 450 milliseconds in males or greater than 470 milliseconds in females), hepatitis (defined as an elevation of alanine transaminase and aspartate transaminase greater than twice the normal values) and tacrolimus intoxication defined by plasmatic levels of ≥20ng/mL regardless nephrotoxicity or neurotoxicity). Anti-COVID-19 protocols in all hospitals were similar and regularly updated according to newly published information. Generally, these included first hydroxychloroquine and lopinavir/ritonavir, darunavir/ritonavir, darunavir/cobicistat and then remdesivir, interferon-beta-1a, intravenous steroid therapy, and tocilizumab in case of clinical deterioration.

Continuous variables were expressed as mean ± standard deviation (SD) or median and interquartile range (IQR) and categorical variables as number of total (n) and percentage (%).

Comparison between groups was performed using Pearson' χ² test for categorical data or Fisher-exact test was applied when the number of cases was less than 5. One-way analysis of variance and t-tests were used for normally continuous distributed data, and nonparametric Kruskal-Wallis test and Mann-Whitney U-test for non-normally distributed variables.

Both univariate and multivariate logistic-regression models were performed to examine the risk factors associated with ARDS. To explore the risk factors associated with patient survival, a

Cox's regression model was used to estimate hazard ratios in an univariate and multivariate analysis, missing data was excluded list-wise. The analyses of patient's survival were censored for death (death certificate date) or recovery (day of discharge and clinical recovery). Due to the relatively small number of death (25) events to avoid overfitting in the model, just 4 variables were chosen for multivariable analysis on the basis of previous findings and clinical constraints.

All P-values were two-tailed and statistical significance level was fixed at P<0.05. SPSS 20.0 software (SPSS Inc., Chicago, IL), STATA16 and GraphPad Prism version 6.0 (GraphPad Software, La Jolla, CA) were used for data management and analysis.

We followed the STROBE Guidelines to report this observational study. Data The median time between appearance of symptoms and admission was 5 (IQR 2-10) days. The most frequent initial clinical manifestation was fever (77.9%), followed by: cough (68.3%), dyspnea (36.5%), myalgia (32.7%), and diarrhea (30.8%) (Table 1, Figure 2 ). Analytical parameters at the admission showed a general inflammatory status with elevation of lactate dehydrogenase (LDH) with a mean of 317.46±147.44 IU/mL, C-reactive protein (CRP) of 78.7 mg/L (IQR 31.9-137.15), D-dimer of 614 ng/mL (IQR 400.75-1344.5), ferritin levels of 574.5 µg/L (IQR 309.75-933.5) and also lymphopenia with a median of 650 cells/mm 3 (IQR 400-1000). Seventeen patients (16%) were admitted without oxygen requirement nor X-ray abnormalities.

Oxygen supply was required at any time point in 85.6% of all the included patients, 54.8% met ARDS criteria and 16.3% were treated with invasive and/or non-invasive ventilation (13.6% and 15.3% respectively). The median time of appearance was 3 (IQR 3-6) days after admission (7 Accepted Article days after symptoms onset). Those who died presented ARDS before those who were alive at the end of follow-up (mean difference -1.44 days, p=0.04). Patients with ARDS showed 11.4 times higher death risk than those without ARDS (95% CI 3.181-41.26, p<0.001). Thirty-two out of 58 patients who developed ARDS survived; among them, the mean time to resolve ARDS was 20.5 days (IQR 14.2-30.7). The analysis of clinical and biological characteristics among patients with or without ARDS is shown in Table 2 . By univariate analysis we found an increased odd for obesity (OR 2.63 (95% CI 1.034-6.714, p=0.04), LDH at admission (OR 1.006 (95%CI 1.001-1.011, p=0.01) and a decreased odd for PaFI/SpO2: OR 0.991 (95% CI 0.985-0.997 p. 0.005). No differences were found in terms of age, type of maintenance immunosuppression use, prevalence of previous lymphopenia, pulmonary disease, baseline graft function or AKI for ARDS. The antiviral therapy did not impact on ARDS outcomes either.

The overall mortality was 26.9%. All deaths were due to ARDS except one that was due to sudden death and another one that was after an aspiration pneumonia. We found that age was related to mortality with an HR of 1.101 (95%CI 1.057-1.157, p<0.001). The mean age for those who survived was 55±11.4 years old and for those who died 70.8±9.4 (p<0.001) ( Table   2 ). There was also an increased risk of mortality for patients presenting ARDS at admission (HR 3.923 (95%CI 1.641-3.942, p=0.002), patients with previous pulmonary disease, increased levels of LDH, CRP, ferritin and low lymphocyte count ( Table 2 -4). Other significant differences in the evolution of analytical parameters between survivors and non-survivors are shown in Figure 3 . In the multivariate cox regression model, we found that age, ARDS and higher baseline LDH were associated with increased risk of death (Table 4) Table 1 ).

Acute kidney injury was present in 47% of the included cohort (Table 5) . Four patients were excluded from this analysis. The majority of patients presented an AKI stage 1 (30%). No differences in terms of age or anti-viral use were found. Interestingly, AKI stage 3 presented a higher median tacrolimus through levels compared to other AKI stage patients (p<0.001).

Mortality was higher in AKI stage 3 patients compared to the rest of the cohort (p<0.05), although in cox regression analysis the presence of AKI at any stage or AKI stage 3 compared to no AKI, were not risk factors associated with death or ARDS. There were no acute graft rejection episodes during the follow-up.

At least one immunosuppressive drug was withdrawn in 91.3% of patients (Supplementary Table 2 ). Intravenous steroid treatment (methylprednisolone 0.5-1mg/kg/day) was used in 52.9 % of cases. CNI withdrawal was higher in patients that developed ARDS (p=0.018), as well as in patient taking an mTORi (p=0.028). We did not find any relationship between type of immunosuppression modification and mortality.

Regarding anti-COVID-19 therapies, different drugs were used (Figure 4a ). Hydroxychloroquine was given to 97.1% and lopinavir/ritonavir to 48.1% of patients. Azythromycin was used in 63.5% of patients. None of these strategies showed any impact on mortality or ARDS, except interferon-beta-1a or tocilizumab that were associated to worse outcomes for ARDS (Supplementary Table 2 ). Importantly, these investigational treatments were related to 28.8%

incidence of adverse effects such as hepatitis (20.2%), tacrolimus toxicity (15.7%), QT prolongation (observed in 5 patients), or gastrointestinal (12.5%) (Figure 4b ).

In early 2020, Spain emerged as one of the most affected countries by the COVID-19 pandemic 12 . This situation forced the discontinuation of many transplant programs worldwide 13 . Transplant Units faced a significant number of infected recipients without evidence-based strategies and many uncertainties regarding the clinical course and prognosis

This article is protected by copyright. All rights reserved In agreement with previous reports of immunocompetent infected population, the most common symptom reported at admission was fever 3 , although one-third of patients were admitted with gastrointestinal complaints, as already described in other transplant reports 14 .

X-ray abnormalities preceded hypoxemia onset, which accounts for the natural history of pulmonary involvement on the general population 4 .

ARDS is considered a severe form of COVID-19 infection and entails greater mortality risk 2 , which was also confirmed in our cohort. Half of our COVID-19 cohort progressed to ARDS, and 50% of them had a fatal outcome. Recently, case report series of in-hospital kidney and other solid organ transplants described similar ARDS incidence 14,15 . Early observations among hospitalized general population reported a 41.8% ARDS incidence 2 , which is in line with our results on kidney transplant recipients. However, in our cohort no age differences were described among patients with and without ARDS, contrary to immunocompetent published cohorts 2 .

It has been suggested that kidney transplant recipients encompass a susceptible group for aggressive manifestations of COVID-19 infection 7,16 due to the ongoing immunosuppression. In our current study, we report an overall mortality rate of 26.9% in consonance with recent reports on kidney and other solid organ transplant patients showing similar fatality rates, ranging from 6% to 30% 7,9,14,16 . General population fatality rates were initially described as 2.3% in China 17 , whereas in Spain, it has reached around 10% 12 . It should be emphasized though, that these figures relate to both hospitalized and non-hospitalized infected patients.

Hence, since published kidney transplant cohorts are mainly composed of hospitalized individuals, these comparisons might be inaccurate. Furthermore, admission criteria are likely to differ between solid organ recipients and the general population (in fact, 16% of our patients were admitted without pneumonia nor hypoxia in our cohort). Nonetheless, recently accepted for publication OpenSAFELY trial suggests an higher hazard ratio for mortality among solid organ recipients 18 .

In terms of acute kidney injury, nearly half of our patients developed renal dysfunction, according to recently published kidney transplant cohorts 15, 19 . AKI occurrence in general population studies ranges from 5 to 10% 20,21 , therefore, kidney transplant recipients entail a group of risk for this complication.

This article is protected by copyright. All rights reserved

The etiology of AKI in patients with COVID-19 remains elusive, and several conditions might act as major contributors, beyond the virus in itself 22 . As a matter of fact, AKI severity was related to tacrolimus trough levels , especially in those with the most severe disfunction (AKI stage 3).

No relationship was found between COVID-19 severity and AKI in our cohort, nor associations with mortality were identified.

A relevant concern derived from SARS-CoV-2 transmissibility is the pre-symptomatic disease stage 23 , thereby resulting in health care professional's contagion and nosocomial patient infection. Fourteen patients were infected within our facilities, with eight deaths in this group.

Most nosocomial infections occurred at the beginning of the pandemic, and all these patients were admitted before the implementation of measures of isolation. Taking into account the inherent limitations of this sample size, these outcomes might be explained by the intrinsic morbidity associated with the ongoing admission in itself 24 . It is of utmost importance to assess the benefits and potential consequences of admission amid this pandemic, which have become one of the reasons for decreased transplantation activity in our country in the last months 13 .

The vast majority of our patients had at least one of their immunosuppressants withdrawn, in consonance with already published works 9, 16 . Mycophenolate mofetil was the most frequently withdrawn medication, regardless of infection severity. In contrast, CNI and mTORi were withheld more frequently in the ARDS group, restricting this strategy only to those patients with severe pulmonary involvement.

Steroid withdrawal was however exceptional, and its administration as intravenous treatment was employed in more than a half (52%) of patients. Our study reports cases detected in the early phase of COVID-19 pandemia, when the efficacy of anti-inflamatory therapies such as steroids were speculative. Thus, in our cohort, steroidal use was mainly reactive to clinical worsening, in order to ensure immunosuppression after CNI, mTORi and antimetabolites withdrawal. However, recently published results from RECOVERY trial 25 have shown that dexamethasone employment reduced mortality in severe COVID-19 cases in the general population, which might support, to some extent, our adopted strategy.

In terms of antiviral treatments, the World Health Organization 10 claimed that there is no existing evidence to recommend any treatment in this regard. However, the use of compassionate treatments has become a widespread practice during the pandemic.

Accordingly, a high proportion of our cohort was treated with some of these drugs

This article is protected by copyright. All rights reserved (Supplementary table 1) . We did not find any differences in terms of outcomes among different treatments, although our study does not allow, by nature, this type of analysis.

Initial reports suggested that the combination of hydroxychloroquine and azithromycin might provide superior viral clearance and improved clinical outcomes, despite significant limitations in its design 26 . However, one of the major concerns about these therapies combinations is cardiotoxicity 27 . In fact, QT prolongation was recorded in 5 individuals, of whom one suffered a sudden death while presenting a mildly symptomatic COVID-19 treated with hydroxychloroquine and azithromycin. Moreover, recently published data from large trials shows absence of clinical benefit from using hydroxychloroquine in COVID-19 patients.

Because of the current available data 25, 28 , along with the adverse effects reported in our cohort, we advise against the use of hydroxychloroquine in COVID-19 kidney transplant recipients.

On the other hand, more than half of our patients received protease inhibitors as adjunctive therapy, resulting in 15.7% of tacrolimus intoxications. Additionally, severe AKI were significantly prevalent among those patients exhibiting tacrolimus overexposure. Thus, given the lack of evidence supporting its use 28 and the concurrent risk of the above-mentioned adverse effects, we support the idea that the employment of investigational anti-COVID-19 therapies must be restricted to randomized controlled trials (RCT), as it has recently shown in a RCT on Remdesivir, which resulted in Food and Drug Administration approval 29 .

At present, there is no available data in terms of risk stratification in kidney transplants recipients affected by COVID-19. As aforementioned, significant rates of COVID-19 progression among patients without pneumonia nor hypoxemia at admission were observed. Therefore, given the unpredictable clinical course of this infection, discharge criteria should differ from the general population at early stages regardless of age, and a strict follow-up must be provided if an outpatient approach is agreed upon. Despite this, we were able to identify certain risk factors for ARDS and death among kidney transplant recipients. We found that obesity was independently associated with ARDS.

Likewise, in the 2009 H1N1 pandemic, an association between hospitalization and obesity was described 30 . Interestingly, although we did not identify older age as a risk factor for ARDS, it was certainly associated with mortality. This data suggests that ARDS might develop indistinctly among young and old kidney transplant recipients; however, once it is established, the elderly would be at most risk for death. Likewise, the preexisting pulmonary disease did

This article is protected by copyright. All rights reserved not conferred additional risk for ARDS development in our cohort, but it was associated (in the univariate analysis) to mortality.

Among laboratory markers, our analysis showed that higher LDH levels at admission were associated with increased odds for both ARDS and death, which might be useful to identify the kidney transplant recipients at higher risk from the admission 19 .

We have to acknowledge some limitations in our study. Firstly, our cohort is not representative of the whole kidney transplant population, since outpatient individuals were not included.

Secondly, we did not consider post-discharge follow-up data, therefore, long term conclusions cannot be drawn. On the other hand, biochemical data (RCP, D-dimer, ferritin) was not available for all established time-points, which may undervalue their association with the main outcomes. Lastly, our findings might be limited and our results underpowered because of the small sample size. As far as we are concerned, however, this is one of the largest published cohorts of COVID-19 infection of a homogeneous cohort of kidney transplant recipients.

Additionally, the exclusive inclusion of patients with definite outcomes in our analysis provides more reliable and clearer information regarding these population outcomes.

In conclusion, older age, obesity and pulmonary disease, along with high baseline LDH levels at presentation and ARDS were associated with poorer outcomes in kidney transplant recipients affected by COVID-19. Half of our population developed ARDS, even those without pneumonia at admission. In terms of pharmacologic strategies, steroids arose as the most commonly used anti-rejection drug during the infection, especially in severe forms, whereas compassionate antiCOVID-19 treatments lead to remarkable rates of adverse effects. A larger study with a longer-term follow up for COVID-19 transplant recipients could answer some of the remaining questions, particularly concerning the treatment, long term prognosis and the most suitable strategy in terms of immunosuppression management in this scenario.

The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.

FA: designed the study, collected the data, analyzed the data, interpreted the data, drafted the article and revised the article critically.

This article is protected by copyright. All rights reserved MN: designed the study, collected the data, analyzed the data, interpreted the data, drafted the article and revised the article critically. ME: designed the study, collected the data, analyzed the data, interpreted the data, drafted the article and revised the article critically.

We thank CERCA Program/Generalitat de Catalunya and the ISCIII RETICS RedinRen RD16/0009/0003 for institutional support. We are grateful to all health coworkers from the Hospitals involved in this study. As the first line defense against COVID-19 pandemic, they faced a very stressful situation in an environment made of uncertainty. We are aware that without their efforts this study could not be realized. Our thoughts are with all transplant recipients affected by COVID-19 and their families. 

This article is protected by copyright. All rights reserved 

This article is protected by copyright. All rights reserved fever at admission; cough at admission; myalgia at admission; anticoagulation; time after transplantation; days from symptoms onset to admission; nosocomial infection. 

A Novel Coronavirus from Patients with Pneumonia in China

Risk Factors Associated With Acute Respiratory Distress

COVID-19 in solid organ transplant recipients: a single-center case series from Spain

Kidney transplant patients with SARS-CoV-2 infection: the brescia renal COVID task force experience

Covid-19 and Kidney Transplantation

Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention

OpenSAFELY: factors associated with COVID-19 death in 17 million patients

COVID-19 and Kidney Transplantation: Results from the TANGO International Transplant Consortium

Acute kidney injury in patients hospitalized with COVID-19

Renal Involvement and Early Prognosis in Patients with COVID-19 Pneumonia

Kidney Involvement in COVID-19: Need for Better Definitions

Temporal dynamics in viral shedding and transmissibility of COVID-19

COVID-19-related Mortality During the First 60 Days After Kidney Transplantation

Low-cost dexamethasone reduces death by up to one third in hospitalised patients with

ALT (IU/mL, median, IQR)

LDH (IU/mL, median, IQR)

CRP (mg/L, median, IQR)

Acute Respiratory Distress Syndrome; CI: confidence interval; CK: creatinine-kinase; eGFR: estimated glomerular filtration rate measured by CKD-EPI

LDH: lactate dehydrogenase; CRP: C-reactive protein; SD: Standard Deviation

This article is protected by copyright. All rights reserved admission (median, IQR)** Initial symptoms (n, %):

This article is protected by copyright. All rights reserved