Introduction

Coronavirus disease 2019 (COVID-19) is the ongoing global pandemic with India becoming its new epicenter. It started in the Hubei province of Wuhan, China, in December 2019 and since then, the impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been felt across the globe claiming over 0.9 million lives as of September 2020.[¹] Patients with comorbidities such as diabetes, hypertension, cardiovascular disease, and malignancy are at increased risk of mortality. While the disease has been well-characterized in general population by numerous large-scale studies,[²³⁴] it is not the case with high risk individuals such as organ transplant recipients. In a recent cohort study of 931 patients, it was found that the risk of mortality was significantly higher among patients on immunosuppressive medications.[⁵] Conflicting evidence arises from other smaller studies where the risk of mortality or severe disease is not increased among patient on immunosuppressive medications.[⁶⁷] There is also a controversy on the effect of immunosuppressive drugs in the setting of cytokine storm in COVID.

The immunosuppressive agents commonly used in renal transplant recipients were found to have anti-viral properties against previous strains of human coronavirus. There is some evidence that corticosteroids through its nonspecific action may be beneficial in the treatment of COVID-19 infection.[⁸⁹] Mycophenolate mofetil (MMF), although had in vitro antiviral properties against middle east respiratory syndrome coronavirus, was found to cause more harm than benefits in in vivo studies.[¹⁰¹¹] Its use is not recommended for human coronavirus infection. Tacrolimus and its derivatives have shown antiviral effect against previous strains of human corona virus, but need more human studies.[¹²¹³¹⁴] There are limited data on the clinical course and outcomes of COVID-19 in renal transplant recipients. We present an analysis of our data, describing the clinical presentations and outcomes of renal transplant recipients admitted with COVID-19.

Materials and Methods

This is a prospective observational study conducted at our Institute, the Madras Medical College. Inclusion criteria - All renal allograft recipients admitted with confirmed COVID-19 by a positive nasopharyngeal swab for SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR), were serially included in the analysis, since the beginning of the outbreak, till August 31, 2020. Exclusion criteria - Those with incomplete data or not willing to give informed consent were excluded. The epidemiological and demographic data were collected through direct interview and by reviewing the patients' previous records. Investigation results, treatment details, and outcome data were recorded by daily telephonic review of the patients and the treating duty team. All the data entered were verified by two physicians independently. All patients underwent laboratory investigations including complete blood count, renal function tests, liver function tests, serum ferritin, C-reactive protein (CRP), and lactate dehydrogenase (LDH).[¹⁵] The collected data were entered into a specific format by one physician and reviewed by the second physician.

Case definition

Acute graft dysfunction

Patients having a functioning graft with baseline serum creatinine of <1.4 mg/dl and fulfilling the KDIGO 2012 criteria for definition of AKI.

Acute on chronic graft dysfunction: Patients having a functioning graft with baseline serum creatinine of ≥ 1.4 mg/dl and not on dialysis and fulfilling the KDIGO 2012 criteria for definition of AKI.

Criteria for diagnosis of mild, moderate, and severe COVID disease are shown in Annexure 1 https://links.lww.com/IJJT/A1.

Institutional management protocol

As per institutional protocol, all renal allograft recipients with COVID-19 were admitted irrespective of severity of symptomatology. All patients underwent chest imaging by computed tomography (CT). The findings were graded radiologically based on the percentage of lung involvement (<25%, 25%–50%, 50%–75%, and >75% lung involvement were assigned grades of 1, 2, 3, and 4, respectively).

Decision on modification of immunosuppression was made on a day-to-day basis based on clinical condition of the patient. Specific therapy included the use of low-molecular-weight heparin (LMWH) (enoxaparin 40 mg subcutaneously daily for 5 days) and escalation of steroids for all patients with radiological lung involvement of >25% (grade 2 and above). Steroids were initially administered in the form of intravenous methylprednisolone 1 mg/kg once daily for 5 days in accordance with the local guidelines at the time, but this was later switched over to intravenous dexamethasone 8 mg once daily for 5–7 days on the basis of newly available trial data.[¹⁶] Patients in our cohort also received remdesivir, tocilizumab, or convalescent plasma therapy based on the institutional treatment protocol [Annexure 1]. Patients with moderate and severe disease received remdesivir therapy since July 2020. A loading dose of 200 mg followed by 100 mg daily for a total duration of 5 days were given for those with estimated glomerular filtration rate (eGFR) >30 ml/min/1.732 m². For patients requiring hemodialysis, a dose of 100 mg was given every alternate day for a total duration of 5–10 days based on their respiratory status followed after each dose by a session of hemodialysis after 4–6 h.[¹⁷] Considering the immunosuppressed state of renal transplant recipients, tocilizumab was avoided but given for those patients in whom interleukin 6 (IL6) level of >100 ng/ml was documented and at the discretion of the treating physician. Convalescent plasma therapy was given for patients with severe disease who worsened despite other measures. For all patients with CT changes of grade 3 and above, a third generation cephalosporin antibiotic was also added to cover super added bacterial infections, especially in the setting of hyperglycemia and steroid use.

Nasopharyngeal swabs for SARS-CoV-2 by RT-PCR were repeated every 3–4 days after admission, until a negative result occurred. Criteria for discharge included clinical recovery, remaining asymptomatic for 3 consecutive days along with a single negative nasopharyngeal swab for SARS-CoV-2.

Data sources and variables

Information relating to symptoms at presentation, history relating to preexisting conditions along with need for respiratory support, were all collected by direct patient interviews, patients' old records and clinical assessment at the time of admission. Laboratory and radiology reports were obtained from the daily consolidated datasheets maintained by the Departments of Internal Medicine and Radiology respectively. Follow-up phone calls were made 2 weeks after discharge, and vital status was ascertained.

Statistical methods

Statistical analysis was performed using IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. (Armonk, NY: IBM Corp.). Qualitative variables were expressed as number and percentage. Quantitative variables were expressed as mean ± standard deviation or as median (interquartile range [IQR]). Pairwise deletion of missing data was performed during analysis.

Appropriate tests for statistical significance were used for comparisons between various groups – the Chi-square test or Fisher's exact test for qualitative data, and the Independent samples t-test or one-way ANOVA for continuous variables and Mann–Whitney U-test or Wilcoxon rank sum test for nonparametric data. For categorical variables, Chi-square test or Fischer's exact test was done. Univariate analysis was performed to identify factors that could predict the risk of severe disease, requirement of ventilatory support, and all statistically significant predictors were entered into a multivariate logistic regression. A two-sided P < 0.05 was considered to be statistically significant.

Patient consent

The patient consent has been taken for participation in the study and for publication of clinical details and images. Patients understand that the names and initials would not be published, and all standard protocols will be followed to conceal their identity.

Ethics statement

The study was approved by the Institutional Ethics Committee of Madras Medical College (IEC ref no. 18082020). This study was carried out as per the regulations of Declaration of Helsinki. The procedure was carried out in accordance with the Declaration of Helsinki and International Council for Harmonization-Good Clinical Practice (ICH-GCP).

Results

Baseline characteristics

Forty-two renal transplant recipients admitted with SARS-COV2 between April 2020 and August 2020 in our institute were analyzed. The mean age of the study population was 41.1 ± 11.4 years. Twenty-two patients (52.4%) belonged to the age group of <40 years, 17 (40.5%) in 41–60 years and three were older than 60 years. Thirty-three (78%) patients were men. Thirty-five (83.3%) were live related donor renal transplant recipients of whom 22 (60%) patients had undergone transplant at our institute and were under our follow-up. Median time since transplant was 4.5 (IQR 2.5–10) years and median duration of hospital stay was 10 days (IQR 7–15.3) [Table 1]. The median duration of follow-up was 41 days (IQR 14.5–59.5). Sixteen (38.1%) patients had hypertension and 18 (42.9%) had diabetes mellitus including NODAT. The median baseline serum creatinine of the study population was 1.5 ± 0.9 mg/dl. Twenty-four (57.1%) patients had chronic graft dysfunction at presentation.

Clinical, laboratory and radiological characteristics

Most of our patients were symptomatic (86.7%) at admission with the most common symptom being fever in 22 patients (52.5%). Breathlessness was observed in 21 patients (50%) and cough in 17 patients (40.5%). Loose stools and myalgia were seen in 18 (42.9%) and 7 (16.6%) patients, respectively. With respect to severity at presentation, 22 (52.4%) were mild, eight (19%) were moderate and 12 (28.6%) presented with severe form of disease. During hospital stay, 22 (52.4%) patients required respiratory support of whom four required high flow nasal oxygen, three required continuous positive airway pressure (CPAP) and two of them required invasive ventilatory support. There was a significantly increased need for respiratory support in individuals with longer duration posttransplant (P < 0.03).

Median neutrophil lymphocyte ratio (NLR) was 5.5 (3.8–12.2) and 16 patients (38.2%) had NLR of >7. The median CRP was 32.4 (16.3–79.1) mg/dl and nine (21%) patients had CRP of >100 mg/dl. On admission, 33 (85.7%) patients had findings suggestive of COVID with majority 24 (57.1%) having radiological grades 1 and 2. Higher grades of CT chest were found in patients requiring respiratory support. Among patients, who required respiratory support and those with severe disease, there was no significant difference in the clinical and laboratory parameters that distinguished patients who succumbed to the illness [Table 2]. None of the parameters were found to be independent predictors of mortality in regression analytic models [Table 3].

Graft dysfunction

Acute worsening of allograft function was observed in 22 (52.4%) patients. Fourteen (65%) of them had acute on chronic graft dysfunction and acute graft dysfunction was noted in eight (35%) patients. Acute enteritis with dehydration was found to be the cause of graft dysfunction in five patients in whom the serum creatinine returned to their baseline values with adequate hydration. Hemodialysis was done in five patients, the indication being volume overload in one and severe metabolic acidosis in four patients. There was no significant difference in requirement of respiratory support in patients with acute (P = 0.16) or acute on chronic graft dysfunction (P = 0.66). Mortality risk was not found to be influenced by the presence of acute graft dysfunction (P = 0.49) or acute on chronic graft dysfunction (P = 0.07). At the end of follow-up, two patients remained dialysis dependent. Nine (43%) patients had serum creatinine returned to their baseline values at the time of discharge.

Immunosuppression and treatment characteristics

Twenty-six (62%) patients were on prednisolone, tacrolimus, and MMF regimen and six (14.3%) patients were on prednisolone, cyclosporine, and azathioprine. Twenty-eight (66.7%) patients were receiving tacrolimus and 34 (81%) patients were on MMF. Reduction of tacrolimus dose was required in 9/28 patients. MMF dose was reduced in 19/34 patients and 7/34 required discontinuation of MMF. In eight of the asymptomatic patients, no modification in dosage of immunosuppression was done. There was no significant difference in outcome between patients using cyclosporine and tacrolimus as the calcineurin inhibitors or mycophenolate and azathioprine as antimetabolites in their regimen. Prednisolone was changed to dexamethasone in 18 (42.9%) patients and intravenous methyl prednisolone in six (14.3%) patients. LMWH, remdesivir, and tocilizumab were given for 25 (59.5%), 10 (23.8%) and four (9.5%) patients, respectively. No difference in outcome was observed with the use of these medications in those with severe disease and those who required respiratory support [Table 2]. Among the 10 patients who received remdesivir, none developed transaminitis during the study.

Risk of severity of disease

Six patients (14.5%) succumbed to the disease, of whom two patients had received invasive ventilation. Cause of death was severe respiratory failure in 5 patients and suspected myocarditis in one patient. Higher age (P = 0.017), baseline chronic graft dysfunction (P = 0.003), higher NLR (P = 0.006), higher CRP (P = 0.008), and higher LDH (P = 0.045) and presence of any degree of breathlessness (P = 0.001) were of statistical significance in patients who developed severe form of the disease. NLR and the inflammatory markers CRP, and LDH were found to be significantly higher among patients requiring oxygen support on presentation (P = 0.006, 0.001, 0.03), respectively [Table 1]. None of the factors were independently associated with mortality in logistic regression analysis. Higher NLR ratio was found to be an independent risk factor for composite outcome of death, use of mechanical ventilation, CPAP, or high flow oxygen therapy [Table 3]. Higher grades on CT chest correlated with the severity of the disease (P = 0.018). There was no association of the disease severity with type of immunosuppressive regimen whether tacrolimus or cyclosporine based (P = 0.57) and MMF or Azathioprine (P = 0.91). One patient continued to be oxygen dependent for >30 days and was suspected to have “long COVID.”

Discussion

Various bodies of literature have come up since December 2019 describing clinical presentations of COVID-19 in the general population but reports on transplant recipients have been limited largely to small case series. The state of Tamil Nadu, India, has been particularly hard-hit, accounting for > 4, 33, 969 documented cases and 7418 deaths as on September 1, 2020.[¹⁸] Due to the limited number of centers with facilities for treating patients with COVID-19 infections particularly renal allograft recipients, our institution has served as the primary referral center from all over the state. This is the largest cohort of renal transplant recipients to our knowledge from India as of date encompassing individuals from the entire state of Tamil Nadu.

Almost half of our patients were younger than 40 years. We did not find age as a significant factor affecting oxygen requirement in patients. This is in contrast to the studies in general population where the incidence of respiratory distress is higher in older age. In a recent multi centric cohort of renal transplant recipients from Spain, no age difference was observed among patients with or without respiratory distress.[¹⁹] Contrary to the pattern in general population, 87% of our patients were symptomatic on presentation with the most frequent presenting complaints being fever, difficulty in breathing and cough. Significant number of patients presented with gastro intestinal symptoms (predominantly diarrhea) similar to observation of Caillard et al. in French transplant registry, possibly attributable to the concomitant use of immunosuppressive drugs. However, symptoms such as anosmia and ageusia were not reported by any of our patients.[²⁰] Various studies reported risk factors for severe disease in general population as elderly age, male sex, comorbidities such as hypertension and diabetes;[²³] however, in our study, we noticed only as the age advances, patients presented with severe form of the disease. In our cohort, 52.4% individuals were requiring oxygen support on presentation which is less compared to 77.2%–84% seen in other series.[¹⁹²¹]

Laboratory features of high NLR, increased CRP and LDH were significant in identifying the disease severity in our patients is in unison with various studies.[²⁰²²] The computerized tomography imaging associated with poor prognosis are bilateral multilobar involvement and subsegmental consolidation. In a case series of 19 transplant patients, the commoner findings in patients with poor prognosis were interlobular septal thickening, multilobar involvement and a higher grade of lung involvement.[²³²⁴] Our study had 87.5% of patients with imaging findings congruent with diagnosis of COVID but majority of them were involving <50% of both the lung fields which can explain a better survival of our patients.

Managing immunosuppression in COVID-19 has generated significant controversies due to the uncertain effects of these drugs on host viral defense and inflammatory response. Our center's strategy of withholding or decreasing antimetabolites and calcineurin inhibitors during the inpatient management of COVID-19 pneumonia did not increase the risk of allograft rejection. In spite of hypotheses of chronic immunosuppression and in vitro antiviral properties of calcineurin inhibitors, we failed to notice any such difference in outcomes among patients on different combinations of immunosuppression.

Acute kidney injury is reported in patients with COVID-19, the incidence of which varied from center to center. The incidence of AKI and the mortality due to the same is at the higher end of the reported range in the renal transplant recipients. AKI is caused both by direct cytopathic effect of the virus, which is evident from the accumulation of viral proteins in the tubules in postmortem studies and also by the consequence of cytokine storm.[²⁵] In our study, acute graft dysfunction was noted in 22 (52.4%) patients and of them, five patients required hemodialysis. Sixteen patients (75%) of those who had worsening graft function showed improvement in renal function at discharge. Two patients died and two other patients remained dialysis dependent at the end of 1 month. Renal biopsy performed on only one patient was suggestive of acute cellular rejection IA. Due to logistic reasons, electron microscopy of graft biopsy specimen was not performed.

In a double-blind randomized placebo controlled trial, remdesivir was found to hasten the recovery and reduce mortality at 14 days whereas the results were negative from another study from China.[²⁶²⁷] In a preliminary report, tocilizumab was found to be useful in a subset of kidney transplant recipients.[²⁸] Among the 10 patients who received remdesivir in our cohort, its use was not associated with significant benefits in outcome. However, none of our patients manifested any adverse effects attributable to remdesivir.

The mortality rate of COVID-19 disease in general population varies in published literature and lies between 8% and 14% with the rate increasing steeply in patients on mechanical ventilation to about 88%.[²⁹] Various studies have reported a mortality rate of 24%–30% in renal transplant recipients.[^193031323334] Recent large international registries reported a higher mortality rate of 22.8%–32% in their transplant cohort.[²⁰²⁹] Our cohort had a mortality rate of 14.5% which is comparatively less possibly due to lesser number of cases required invasive ventilation and mandatory admission of patients even while asymptomatic. However, the mortality rate was significantly higher in our cohort as compared to the general population of the state where the case fatality rate was 1.9%.[¹⁸] Furthermore, the predominance of younger individuals in our study as compared to other cohorts might explain the reduced mortality rate [Table 4]. In a recent report of 144 renal transplant recipients from the TANGO consortium, no significant association existed between mortality and immunosuppression withdrawal, use of drugs such as tocilizumab and hydroxychloroquine. The risk of mortality increased with older age, higher respiratory rate, higher LDH, IL-6, procalcitonin levels, and lower eGFR.[²⁹] Our study did not reveal increased risk of mortality in any of the subgroups analyzed and also was not associated with any immunosuppressive regimen or specific therapy.

Limitations

Comparison of various therapeutic agents and long-term follow-up of the patients was not done in our study. Renal biopsy could not be performed in all patients with acute worsening of graft function.

Conclusions

Our largest cohort of patients from India showed higher incidence of acute graft dysfunction in patients with COVID-19 with significant mortality. There were no independent risk factors associated with mortality in our cohort. Larger studies with long-term follow-up are needed to further establish the clinical course of COVID-19 in renal transplant recipients and the appropriate level of immunosuppression that could prevent the rejection of graft and at the same time not making the patient vulnerable to COVID-19 infection.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Acknowledgement

We would like to thank the Dean and all the members of COVID care team of Madras Medical College and Rajiv Gandhi Government General Hospital.

Supplemental Digital Content

• IJJT_15_3_2022_08_20_ARUMUGAM_13720_SDC137.pdf; [PDF] (213 KB)