*2.2. Database Creation*

As already described in our preliminary reports, an institutional Research Electronic Data Capture database was created, populated by all consecutive eligible de-identified subjects [8,18]. The collected data included patient demographic characteristics, comorbidities, transplant details, immunosuppression regimen, and SARS-CoV-2-specific treatment and outcomes [8,18]. Patients were followed for a 90-day period from the time of diagnosis [8,18].

#### *2.3. Statistical Analysis*

Subjects were divided into groups of survivors and fatalities at the end of the 90-day follow-up period. Categorical variables were reported as the number and percentage of the total group (%) and compared using the Fisher's exact test [32,33]. Continuous variables were reported as a median and interquartile range (lower quartile, upper quartile) and compared using the Wilcoxon rank sum test [8,32,33]. A univariate Cox regression model was performed on the above-discussed variables and a Kaplan–Meier survival curve was constructed by age group [32].

#### **3. Results**

A total of 103 patients were enrolled, with 76 kidney-transplants recipients, 23 livertransplant recipients, and 4 simultaneous liver–kidney-transplant (SLK) patients. There was a total of 10 90-day mortalities and 93 surviving patients. Patient demographic information, transplant type, comorbidities, and immunosuppression-regimen descriptions are shown in Table 1. Age, gender, transplant type, and comorbidities were statistically similar between the groups. There was a statistically significant difference (*p* < 0.001) between the median age of 67 and 52 in the dead and survivor groups, respectively. Significant differences also existed between groups in terms of immunosuppression regimens, namely Tacrolimus (*p* = 0.037) and Cyclosporine (*p* = 0.029).

**Table 1.** Patient Demographics, Transplant Type, Comorbidities, and Immunosuppression. Age reported as Median (IQR); analyzed with Wilcoxon rank sum test. Categorical variables reported as n (%); analyzed with Fisher's exact test.


SLK, simultaneous-liver kidney transplant; MMF, mycophenolate mofetil.

A univariate Cox regression model was performed for ages greater than 60 and immunosuppression regimen, shown in Table 2. Patients aged >60 were associated with a higher hazard ratio (HR) (HR = 10, *p* = 0.0034), as well as Cyclosporine (HR = 6.1, *p* = 0.0089) or Belatacept for the immunosuppression maintenance (HR = 6.1, *p* = 0.022), contrary to Tacrolimus (HR = 0.23, *p* = 0.022). No significant mortality risk or benefit was seen in patients taking prednisone, MMF, Sirolimus, or Azathioprine.


**Table 2.** Univariate Cox Regression Model of Selected Variables.

MMF, mycophenolate mofetil.

A Kaplan–Meier survival curve and the associated life table are shown in Figure 1 and Table 3, respectively. No SARS-CoV-2-related deaths within 90 days post-infection occurred in the youngest (20–51) age group. For the rest of the groups, deaths occurred 2 to 45 days post-SARS-CoV-2 diagnosis. The oldest patient group (aged ≥ 72) had the least survival probability (75%) compared to the rest (reference 20–51 years; *p* < 0.001).

**Figure 1.** Kaplan-Meier survival curve of unvaccinated SARS-CoV-2 positive solid organ transplant recipients, stratified by age groups (years): 20–51, 51–63, 63–72, >72. Patient survival was inferior in the oldest age group (*p* < 0.0001).

**Table 3.** Life Table by Age Group.

