Relative and absolute cancer risks among Nordic kidney transplant recipients—a population-based study

Kidney transplant recipients (KTRs) have an increased cancer risk compared to the general population, but absolute risks that better reflect the clinical impact of cancer are seldom estimated. All KTRs in Sweden, Norway, Denmark, and Finland, with a first transplantation between 1995 and 2011, were identified through national registries. Post-transplantation cancer occurrence was assessed through linkage with cancer registries. We estimated standardized incidence ratios (SIR), absolute excess risks (AER), and cumulative incidence of cancer in the presence of competing risks. Overall, 12 984 KTRs developed 2215 cancers. The incidence rate of cancer overall was threefold increased (SIR 3.3, 95% confidence interval [CI]: 3.2–3.4). The AER of any cancer was 1560 cases (95% CI: 1468–1656) per 100 000 person-years. The highest AERs were observed for nonmelanoma skin cancer (838, 95% CI: 778–901), non-Hodgkin lymphoma (145, 95% CI: 119–174), lung cancer (126, 95% CI: 98.2–149), and kidney cancer (122, 95% CI: 98.0–149). The five- and ten-year cumulative incidence of any cancer was 8.1% (95% CI: 7.6–8.6%) and 16.8% (95% CI: 16.0–17.6%), respectively. Excess cancer risks were observed among Nordic KTRs for a wide range of cancers. Overall, 1 in 6 patients developed cancer within ten years, supporting extensive post-transplantation cancer vigilance.     

Observational study of risk factors associated with clinical outcome among elderly kidney transplant recipients in Sweden – a decade of follow-up

Kidney transplantation (Ktx) in elderly has become increasingly accepted worldwide despite their higher burden of comorbidities. We investigated important risk factors affecting long-term patient and graft survival. We included all (n = 747) Ktx patients >60 years from 2000 to 2012 in Sweden. Patients were age-stratified, 60–64, 65–69 and >70 years. Follow-up time was up to 10 years (median 7.9 years, 75% percentile >10 years). Primary outcome was 10-year patient survival in age-stratified groups. Secondary outcomes were 5-year patient and graft survival in age-stratified groups and the impact of risk factors including Charlson comorbidity index (CCI) on patient and graft survival. Mortality was higher in patients >70 years, after 10 years (HR 1.94; 95% CI 1.24–3.04; P = 0.004). Males had a higher 10-year risk of death (HR 1.39; CI 95% 1.04–1.86; P = 0.024). Five-year patient survival did not differ between age groups. In multivariate Cox analysis (n = 500), hazard ratio for 10-year mortality was 4.6 in patients with CCI ≥7 vs. <4 (95% CI 2.42–8.62; P = 0.0001). Higher CCI identified ESKD patients with 4.6 times higher risk of death after Ktx. We suggest that this index should be used as a part of the preoperative evaluation in elderly.     

The association of living donor source with patient and graft survival among kidney transplant recipients in the ERA-EDTA Registry – a retrospective study

In this study we aimed to compare patient and graft survival of kidney transplant recipients who received a kidney from a living-related donor (LRD) or living-unrelated donor (LUD). Adult patients in the ERA-EDTA Registry who received their first kidney transplant in 1998–2017 were included. Ten-year patient and graft survival were compared between LRD and LUD transplants using Cox regression analysis. In total, 14 370 patients received a kidney from a living donor. Of those, 9212 (64.1%) grafts were from a LRD, 5063 (35.2%) from a LUD and for 95 (0.7%), the donor type was unknown. Unadjusted five-year risks of death and graft failure (including death as event) were lower for LRD transplants than for LUD grafts: 4.2% (95% confidence interval [CI]: 3.7–4.6) and 10.8% (95% CI: 10.1–11.5) versus 6.5% (95% CI: 5.7–7.4) and 12.2% (95% CI: 11.2–13.3), respectively. However, after adjusting for potential confounders, associations disappeared with hazard ratios of 0.99 (95% CI: 0.87–1.13) for patient survival and 1.03 (95% CI: 0.94–1.14) for graft survival. Unadjusted risk of death-censored graft failure was similar, but after adjustment, it was higher for LUD transplants (1.19; 95% CI: 1.04–1.35). In conclusion, patient and graft survival of LRD and LUD kidney transplant recipients was similar, whereas death-censored graft failure was higher in LUD. These findings confirm the importance of both living kidney donor types.     

Parathyroid resistance to FGF23 in kidney transplant recipients: back to the past or ahead to the future?

Fibroblast growth factor 23 (FGF23) modulates the metabolism of minerals and vitamin D. In chronic kidney disease (CKD), this process is disturbed owing to decreased parathyroid expression of FGF23's receptor complex Klotho-FGF receptor 1. In this issue, Krajisnik and colleagues demonstrate that similar alterations occur in parathyroid glands from kidney transplant recipients in association with a decline in allograft function. Is it possible that these data can be extrapolated to general early-stage CKD patients?     

Longitudinal assessment of the CXCL10 blood and urine concentration in kidney transplant recipients with BK polyomavirus replication—a retrospective study

In kidney transplant recipients (KTRs), BK polyomavirus (BKPyV) replication may progress to polyomavirus-associated nephropathy (PVAN). In this retrospective study, we assessed the chemokine CXCL10 in urine and blood samples consecutively acquired from 85 KTRs who displayed different stages of BKPyV replication and eventually developed PVAN. In parallel to progression toward PVAN, CXCL10 gradually increased in blood and urine, from baseline (prior to virus replication) to BKPyV DNAuria (median increase in blood: 42.15 pg/ml, P = 0.0156), from mere DNAuria to low- and high-level BKPyV DNAemia (median increase: 52.60 and 87.26 pg/ml, P = 0.0010 and P = 0.0002, respectively) and peaked with histologically confirmed PVAN (median increase: 145.00 pg/ml, P < 0.0001). CXCL10 blood and urine levels significantly differed among KTRs with respect to simultaneous presence of human cytomegalovirus (P < 0.001) as well as in relation to the clinical severity of respective BKPyV DNAemia episodes (P = 0.0195). CXCL-10 concentrations were particularly lower in KTRs in whom BKPyV DNAemia remained without clinical evidence for PVAN, as compared to individuals who displayed high decoy cell levels, decreased renal function and/or biopsy-proven PVAN (median blood concentration: 266.97 vs. 426.42 pg/ml, P = 0.0282). In conclusion, in KTRs CXCL10 rises in parallel to BKPyV replication and correlates with the gradual development of PVAN.     

Association between post-transplant donor-specific antibodies and recipient outcomes in simultaneous liver–kidney transplant recipients: single-center,cohort study

There is a dearth of published data regarding the presence of post-transplant donor-specific antibodies (DSA), especially C1q-binding DSA (C1q+DSA), and patient and kidney allograft outcomes in simultaneous liver–kidney transplant (SLKT) recipients. We conducted a retrospective cohort study consisted of 85 consecutive SLKT patients between 2009 and 2018 in our center. Associations between presence of post-transplant DSA, including persistent and/or newly developed DSA and C1q+DSA, and all-cause mortality and the composite outcome of mortality, allograft kidney loss, and antibody-mediated rejection were examined using unadjusted and age and sex-adjusted Cox proportional hazards and time-dependent regression models. The mean age at SLKT was 56 years and 60% of the patients were male. Twelve patients (14%) had post-transplant DSA and seven patients (8%) had C1q+DSA. The presence of post-transplant DSA was significantly associated with increased risk of mortality (unadjusted model: Hazard Ratio (HR) = 2.72, 95% confidence interval (CI): 1.06–6.98 and adjusted model: HR = 3.20, 95% CI: 1.11–9.22) and the composite outcome (unadjusted model: HR = 3.18, 95% CI: 1.31–7.68 and adjusted model: HR = 3.93, 95% CI: 1.39–11.10). There was also higher risk for outcomes in recipients with C1q+DSA compared the ones without C1q+DSA. Post-transplant DSA is significantly associated with worse patient and kidney allograft outcomes in SLKT. Further prospective and large cohort studies are warranted to better assess these associations.     

The impact of severe acute kidney injury requiring renal replacement therapy on survival and renal function of heart transplant recipients – a UK cohort study

Severe acute kidney injury (AKI), defined as requiring renal replacement therapy (RRT), is associated with higher mortality postheart transplantation, but its long-term renal consequences are not known. Anonymized data of 3365 patients, who underwent heart transplantation between 1995 and 2017, were retrieved from the UK Transplant Registry. Multivariable binary logistic regression was performed to identify risk factors for severe AKI requiring RRT, Kaplan–Meier analysis to compare survival and renal function deterioration of the RRT and non-RRT groups, and multivariable Cox regression model to identify predicting factors of mortality and end-stage renal disease (ESRD). 26.0% of heart recipients received RRT post-transplant. The RRT group has lower survival rates at all time points, especially in the immediate post-transplant period. However, conditional on 3 months survival, older age, diabetes and coronary heart disease, but not post-transplant RRT, were the risk factors for long-term survival. The predicting factors for ESRD were insulin-dependent diabetes, renal function at transplantation, eGFR decline in the first 3 months post-transplant, post-transplant severe AKI and transplantation era. Severe AKI requiring RRT post-transplant is associated with worse short-term survival, but has no impact on long-term mortality. It also accelerates recipients’ renal function deterioration in the long term.     

Does tuberculosis after kidney transplantation follow the trend of tuberculosis in general population?

Despite improvement in graft survival, infection continues to be an important cause of morbidity and mortality after kidney transplantation. We analyzed the clinical courses and outcomes of 16 transplanted patients with positive cultures for mycobacterium tuberculosis. In the course of a 20 year period, there were 13 cases of tuberculosis registered that developed in 456 patients who underwent kidney transplantation in our department, and in three refugees transplanted in other centers (a prevalence of 3.13%). Five of them developed tuberculous infections during 1997. Five patients had residual tuberculosis in preoperative chest X-ray, and specific pyelonephritis as an underlying kidney disease in two of them. All patients with treated with triple immunosuppressives. Before tuberculosis onset, 14 patients experienced one or more episodes of acute rejection and were treated with steroid pulses, ALG or OKT3. Tuberculosis was diagnosed after a period of 1.5 months to 10 years after transplantation. At the time of an infection, the graft function was normal in eight patients and chronic graft failure was evident in eight patients (sCr 210-700 micromol/L). The infection was pulmonary in 12 patients; urinary in two; disseminated in two; pulmonary and urinary, pulmonary and intestinal, and pancytopenia in one patient. All patients were treated with rifampicin and isoniazid in addition to ethambutol for the first two-month period. Treatment lasted from 1-22 months. With 14 patients favorable microbiological responses were registered. Two patients died within the first six months (both with disseminated disease), and the mortality rate was 14.3%. Throughout the followup period, the graft function remained stable and normal in eight patients who had normal graft function at the time of infection onset. Although six patients recovered, progressive graft failure developed and hemodialysis was restarted in one patient two months after antituberculous therapy introduction, and in two patients three years later. Four patients died 2-14 months after AT therapy withdrawal. The causes of death were severe liver failure, cerebrovascular insult and CMV.     

Urinary sulfate excretion and risk of late graft failure in renal transplant recipients – a prospective cohort study

Hydrogen sulfide (H₂S), produced from metabolism of dietary sulfur-containing amino acids, is allegedly a renoprotective compound. Twenty-four-hour urinary sulfate excretion (USE) may reflect H₂S bioavailability. We aimed to investigate the association of USE with graft failure in a large prospective cohort of renal transplant recipients (RTR). We included 704 stable RTR, recruited at least 1 year after transplantation. We applied log-rank testing and Cox regression analyses to study association of USE, measured from baseline 24 h urine samples, with graft failure. Median age was 55 [45–63] years (57% male, eGFR was 45 ± 19 ml/min/1.73 m²). Median USE was 17.1 [13.1–21.1] mmol/24 h. Over median follow-up of 5.3 [4.5–6.0] years, 84 RTR experienced graft failure. RTR in the lowest sex-specific tertile of USE experienced a higher rate of graft failure during follow-up than RTR in the middle and highest sex-specific tertiles (18%, 13%, and 5%, respectively, log-rank P < 0.001). In Cox regression analyses, USE was inversely associated with graft failure [HR per 10 mmol/24 h: 0.37 (0.24–0.55), P < 0.001]. The association remained independent of adjustment for potential confounders, including age, sex, eGFR, proteinuria, time between transplantation and baseline, BMI, smoking, and high sensitivity C-reactive protein [HR per 10 mmol/24 h: 0.51 (0.31–0.82), P = 0.01]. In conclusion, this study demonstrates a significant inverse association of USE with graft failure in RTR, suggesting high H₂S bioavailability as a novel, potentially modifiable factor for prevention of graft failure in RTR.     

Serum uric acid levels in kidney transplant recipients: A cause for concern? A review of recent literature

The impact of elevated serum uric acid levels i.e., hyperuricemia, on native and transplant chronic kidney disease progression has been debated. This literature review presents an analysis of multiple studies exploring the relationship between serum uric acid levels and kidney transplant outcomes. The review includes a summary of the pathophysiology of hyperuricemia and gout, a review of urate-lowering therapies, and an appraisal of multiple studies examining the association or lack thereof between serum uric acid level and kidney transplant outcomes. Based on these studies, elevated serum uric acid levels may contribute to CKD progression in kidney transplant recipients. In this review, we also summarize current literature to highlight risk factors associated with hyperuricemia as well as the need for further investigation to monitor and manage hyperuricemia in kidney transplant recipients.     

Is the risk of cardiovascular disease increased in living kidney donors? A Danish population-based cohort study

Reduced renal function is associated with cardiovascular disease (CVD); however, how living donor nephrectomy affects the risk of CVD remains controversial. We conducted a nationwide cohort study including living kidney donors in Denmark from 1996 to 2018 to assess the risk of hypertension, atrial fibrillation/flutter (AF), major adverse cardiovascular events (MACE; composite of myocardial infarction, ischemic stroke, and death) and death after living kidney donation. As comparisons we identified: a cohort of healthy individuals from the general population and an external blood donor cohort. We followed kidney donors (1,103 when compared with the general population cohort; 1,007 when compared with blood donors) for a median of 8 years. Kidney donors had an increased risk of initiating treatment for hypertension when compared with blood donors (standardized incidence ratio [SIR], 1.40; 95% confidence interval [CI], 1.17–1.66) but they did not have increased risk of MACE neither when compared with the general population cohort (hazard ratio, 0.68; 95% CI, 0.52–0.89) nor with blood donors (SIR, 1.17; 95% CI, 0.88–1.55). Neither did they have increased risks of AF and death. Thus, living kidney donation may be associated with increased risk of hypertension; however, we did not identify increased risks of CVD or death.     

Toward a conditional approach to anonymity? An explorative multicenter longitudinal study among anonymous living kidney donors and recipients

Anonymity between living donors and recipients is a topic of discussion among transplant professionals. This longitudinal study explored living kidney donors’ and patients’ perspectives on anonymity. Prior to surgery (T0) and 3 months afterward (T1), participants in unspecified or specified indirect donation programs completed a questionnaire on their experiences with and attitudes toward anonymity as well as demographic and medical characteristics. Nonparametric tests were used to assess group differences and associations. Participants were content with anonymity at T0 and T1. Fourteen and 23% wanted to meet at T0 and T1, respectively. If the other party expressed the wish to meet, 50% (T0) and 55% (T1) would be willing to meet. Most participants agreed that meeting should be allowed if both parties agree. Attitude toward anonymity did not differ between donors/recipients, nor between T0/T1 and unspecified/specified indirect donation programs. This study showed that most donors and recipients who participated in anonymous donation schemes are in favor of a conditional approach to anonymity. Guidelines on how to revoke anonymity if both parties agree are needed and should include education about pros and cons of (non‐) anonymity and a logistical plan on how, when, where, and by whom anonymity should be revoked.