The coronavirus disease 2019 (COVID-19) pandemic has posed a significant challenge to physicians and healthcare systems worldwide. Evidence about kidney transplant (KTx) recipients is still limited. A systematic literature review was performed. We included 63 articles published from 1 January until 7 July 2020, reporting on 420 adult KTx recipients with confirmed COVID-19. The mean age of patients was 55 ± 15 years. There was a male predominance (67%). The majority (74%) were deceased donor recipients, and 23% were recently transplanted (<1 year). Most patients (88%) had at least one comorbidity, 29% had two, and 18% three. Ninety-three percent of cases were hospitalized. Among them, 30% were admitted to the intensive care unit, 45% developed acute respiratory distress syndrome, and 44% had acute kidney injury with 23% needing renal replacement therapy. From the hospitalized patients a total of 22% died, 59% were discharged, and 19% were still in hospital at the time of publication. Immunosuppression was reduced in 27%, discontinued in 31%, and remained unchanged in 5%. Hydroxychloroquine was administered to 78% of patients, antibiotics to 73%, and antivirals to 30% while 25% received corticosteroid boluses, 28% received anti-interleukin agents, and 8% were given immunoglobulin. The main finding of our analysis was that the incidence of COVID-19 among kidney transplant patients is not particularly high, but when they do get infected, this is related to significant morbidity and mortality.

<b><i>Introduction:</i></b> Hypertension is the most prominent risk factor in kidney transplant recipients (KTRs). No study so far assessed in parallel the prevalence, control, and phenotypes of blood pressure (BP) or the accuracy of currently recommended office BP diagnostic thresholds in diagnosing elevated ambulatory BP in KTRs. <b><i>Methods:</i></b> 205 stable KTRs underwent office BP measurements and 24-h ambulatory BP monitoring (ABPM). Hypertension was defined as follows: (1) office BP ≥140/90 mm Hg or use of antihypertensive agents following the current European Society of Cardiology/European Society of Hypertension (ESC/ESH) guidelines, (2) office BP ≥130/80 mm Hg or use of antihypertensive agents following the current American College of Cardiology/American Heart Association (ACC/AHA) guidelines, (3) ABPM ≥130/80 mm Hg or use of antihypertensive agents, and (4) ABPM ≥125/75 mm Hg or use of antihypertensive agents. <b><i>Results:</i></b> Hypertension prevalence by office BP was 88.3% with ESC/ESH and 92.7% with ACC/AHA definitions compared to 94.1 and 98.5% at relevant ABPM thresholds. Control rates among hypertensive patients were 69.6 and 43.7% with office BP compared to 38.3 and 21.3% with ABPM, respectively. Both for prevalence (κ-statistics = 0.52, <i>p</i> &#x3c; 0.001 and 0.32, and <i>p</i> &#x3c; 0.001) and control rates (κ-statistics = 0.21, <i>p</i> &#x3c; 0.001 and 0.22, and <i>p</i> &#x3c; 0.001, respectively), there was moderate or fair agreement of the 2 techniques. White-coat and masked hypertension were diagnosed in 6.7 and 39.5% of patients at the 140/90 threshold and 5.9 and 31.7% of patients at the 130/80 threshold. An office BP ≥140/90 mm Hg had 35.3% sensitivity and 84.9% specificity for the diagnosis of 24-h BP ≥130/80 mm Hg. An office BP ≥130/80 mm Hg had 59.7% sensitivity and 73.9% specificity for the diagnosis of 24-h BP ≥125/75 mm Hg. Receiver operating curve analyses confirmed this poor diagnostic performance. <b><i>Conclusions:</i></b> At both corresponding thresholds studied, ABPM revealed particularly high hypertension prevalence and poor BP control in KTRs. Misclassification of KTRs by office BP is substantial, due to particularly high rates of masked hypertension. The diagnostic accuracy of office BP for identifying elevated ambulatory BP is poor. These findings call for a wider use of ABPM in KTRs.

Patients with chronic kidney disease (CKD), particularly those with end-stage renal disease (ESRD), are at increased risk of cardiovascular events and mortality. The spectrum of arterial remodeling in CKD and ESRD includes atheromatosis of middle-sized conduit arteries and, most importantly, the process of arteriosclerosis, characterized by increased arterial stiffness of aorta and the large arteries. Longitudinal studies showed that arterial stiffness and abnormal wave reflections are independent cardiovascular risk factors in several populations, including patients with CKD and ESRD. Kidney transplantation is the treatment of choice for patients with ESRD, associated with improved survival and better quality of life in relation to hemodialysis or peritoneal dialysis. However, cardiovascular mortality in transplanted patients remains much higher than that in general population, a finding that is at least partly attributed to adverse lesions in the vascular tree of these patients, generated during the progression of CKD, which do not fully reverse after renal transplantation. This article attempts to provide an overview of the field of arterial stiffness in renal transplantation, discussing in detail available studies on the degree and the associations of arterial stiffness with other co-morbidities in renal transplant recipients, the prognostic significance of arterial stiffness for cardiovascular events, renal events and mortality in these individuals, as well as studies examining the changes in arterial stiffness following renal transplantation.