Risk factors of covid-19 in kidney transplant recipients

Purpose: Kidney transplant recipients have been shown to develop a severe form of coronavirus disease (COVID-19) that poses a significant mortality risk. The aim of this study was to evaluate risk factors associated with acquiring COVID-19 in our kidney transplant population. Methods: We retrospectively reviewed the medical records of all kidney transplant recipients in our national transplant registry. There were 249 out of 693 kidney transplant recipients who underwent SARS-CoV-2 infection testing by August 1st, 2020. All testing was done by government using RT-PCR of throat and nasal swabs. Forty-three of the tested patients had positive COVID-19 (17%), while the remaining 206 were negative. Mann-Whitney and Fisher's exact tests were used to study the different continuous and categorical variables, respectively. Results: Among patients tested for COVID-19, Asian ethnicity (37% vs. 16%, P=0.003), history of hypertensive nephropathy (23% vs. 9%, P=0.01) and deep vein thrombosis (12% vs.1%, P=0.002) were statistically significant in COVID-19 positive group compared to COVID-19 negative group. Tacrolimus trough level at the time of COVID-19 testing was also significantly higher in COVID-19 positive patients (7.7 ng/mL vs. 6.6 ng/mL, P=0.03). Recipient age, gender, year of transplant, donor type, maintenance immunosuppression, flu vaccine within 1 year and use of ACE inhibitors or ARBs were all similar in both groups. Most patients with positive COVID-19 were symptomatic at the time of testing compared to negative patients (84% vs. 18%, P=0.0001). However, close contact with positive COVID-19 people was similar in both groups (14% vs. 14%, P=1). Conclusions: Prevention and reduction of COVID-19 infection development is crucial in kidney transplant recipients to avoid unfavorable outcomes. With the widespread of COVID-19 worldwide, avoiding exposure might not be possible. Our results suggest that targeting lower tacrolimus trough levels may reduce the risk of acquiring SARS-CoV-2 infection.