Glomerular Filtration Rate Slopes Have Significantly Improved Among Renal Transplants in the United States

Impact of acute kidney injury on graft outcomes of deceased donor kidney transplantation: A nationwide registry-based matched cohort study in Korea

Background

Favorable long-term and short-term graft survival and patient survival after kidney transplantation (KT) from deceased donors with acute kidney injury (AKI) have been reported. However, few studies have evaluated effects of donor AKI status on graft outcomes after KT in Asian population. Thus, the purpose of this study was to evaluate graft function after KTs from donors with AKI compared to matched KTs from donors without AKI using a multicenter cohort in Korea.

Methods

We analyzed a total of 1,466 KTs collected in Korean Organ Transplant Registry between April 2014 and December 2017. KTs from AKI donors (defined as donors with serum creatinine level ≥ 2 mg/dL) and non-AKI donors (275 cases for each group) were enrolled using a 1:1 propensity score matching. Graft outcomes including graft and patient survival, delayed graft function (DGF), rejection rate, and serially measured estimated glomerular filtration rate (eGFR) were evaluated.

Results

After propensity matching, KTs from AKI donors showed higher rate of DGF (44.7% vs. 24.0%, p < 0.001). However, the rejection rate was not significantly different between the two groups (KTs from AKI donors vs. KTs from non-AKI donors). eGFRs measured after 6 months, 1 year, 2 years and 3 years were not significantly different by donor AKI status. With median follow-up duration of 3.52 years, cox proportional hazards models revealed hazard ratio of 0.973 (95% confidence interval [CI], 0.584 to 1.621), 1.004 (95% CI, 0.491 to 2.054) and 0.808 (95% confidence interval [CI], 0.426 to 1.532) for overall graft failure, death-censored graft failure and patient mortality, respectively, in KTs from AKI donors compared to KTs from non-AKI donors as a reference.

Conclusions

KTs from AKI donors showed comparable outcomes to KTs from non-AKI donors, despite a higher incidence of DGF. Results of this study supports the validity of using kidneys from deceased AKI donors in Asian population.

Defining a minimal clinically meaningful difference in 12-month estimated glomerular filtration rate for clinical trials in deceased donor kidney transplantation

BACKGROUND

A Minimal Clinically Meaningful Difference (MCMD) has not been defined for Estimated glomerular filtration rate (eGFR). Our goal was to define the MCMD for eGFR anchored to kidney graft failure.

METHODS

A systematic review of studies with 12-month eGFR and subsequent renal graft failure was conducted. For observational studies, we calculated hazard ratio (HR) differences between adjacent eGFR intervals weighted by population distribution. Interventional trials yielded therapeutically induced changes in eGFR and failure risk. OPTN data analysis divided 12-month eGFR into bands for Cox regressions comparing adjacent eGFR bands with a death-censored graft survival outcome.

RESULTS

Observational studies indicated that lower eGFR was associated with increased death-censored graft failure risk; each 5 ml/min/1.73 m2 12-month eGFR band associated with a weighted incremental HR = 1.12 to 1.23. Clinical trial data found a 5 ml/min/1.73 m2 difference was associated with incremental HR = 1.16 to 1.35. OPTN analyses showed weighted mean HRs across 10, 7, and 5 ml/min/1.73 m2 bands of 1.47, 1.30, and 1.19.

CONCLUSIONS

A 5 ml/min/1.73 m2 difference in 12-month eGFR was consistently associated with ~20% increase in death-censored graft failure risk. The magnitude of effect has been interpreted as clinically meaningful in other disease states and should be considered the MCMD in renal transplantation clinical trials.

Persistent hyperparathyroidism as a risk factor for long-term graft failure: the need to discuss indication for parathyroidectomy

BACKGROUND

Although a successful kidney transplant (KTx) improves most of the mineral and bone disorders (MBD) produced by chronic kidney disease (CKD), hyperparathyroidism may persist (pHPT). Current guidelines recommend parathyroidectomy if serum parathormone is persistently elevated 1 year after KTx, because pHPT has been recently associated with poor graft outcomes. However, whether patients with pHPT and adequate renal function are at risk for long-term graft failure is unknown.

METHODS

Longitudinal follow-up of 911 adults submitted to KTx between January 2005 and December 2014, with estimated glomerular filtration rate (eGFR) ≥ 30 mL/min 1 year after surgery. Clinical and laboratory data were collected from electronic database. Graft failure was defined as return to dialysis.

RESULTS

Overall, 62% of the patients were classified as having pHPT 1 year after KTx. After a mean follow-up time of 47 months, there were 59 graft failures (49 in pHPT and 10 in non-pHPT group, P = .003). At last follow-up, death-censored graft survival was lower in the pHPT group (P = .009), even after adjustment for age at KTx, donor age, donor type, acute rejection, parathyroidectomy, and eGFR at 1 year after transplantation (odds ratio [OR] 1.99; 1.004-3.971; P = .049). A PTH of 150 pg/mL at 6 months was the best cutoff to predict pHPT at 1 year (specificity = 92.1%).

CONCLUSION

Having pHPT after a successful KTx increases the long-term risk of death-censored graft failure. This result highlights the need for better recognition and management of CKD-MBD before and during the first year after KTx, and opens a discussion on the more appropriate timing to perform parathyroidectomy.

Living donor kidney allograft survival ≥ 50 years

The first successful kidney transplant occurred in 1954. Since then, long-term graft survival has been an elusive idealistic goal of transplantation. Yet 62 years later, we know of only 6 kidney transplant recipients who have achieved ≥  50-year graft survival while being on no immunosuppression or a substantially reduced regimen. Herein, we report graft survival  ≥ 50 years in 2 living donor recipients who have been maintained on standard-of-care immunosuppression the entire time. For our 2 recipients, their living donor's altruism altered the course, length, and quality of their life, which by all accounts can be deemed normal: They attended college, held jobs, had successful pregnancies, raised families, and were productive members of society. Both donors are still alive and well, more than 50 years post-donation; both have an acceptable GFR and normal blood pressure, with hyperlipidemia as their only medical problem. These 2 intertwined stories illustrate the tremendous potential of a successful kidney transplant: long-term survival with a normal lifestyle and excellent quality of life, even after more than 5 decades on full-dose immunosuppression.

Efficacy and safety of conversion from cyclosporine to everolimus in living-donor kidney transplant recipients: an analysis from the ZEUS study

Conversion of living-donor kidney transplant patients from calcineurin inhibitor therapy to an mTOR inhibitor is poorly documented. In the prospective, multicentre ZEUS study, 300 kidney transplant recipients without prior rejection (Banff grade >1) and serum creatinine ≤265 μmol/l were randomized to continue cyclosporine or convert to everolimus at 4.5 months post-transplant. In a post hoc analysis of 80 living-donor recipients, adjusted estimated GFR (Nankivell) at month 12 (the primary endpoint) was 74.3 (95% CI [70.7, 77.9]) ml/min/1.73 m(2) with everolimus versus 63.8 (95% CI [60.0, 67.7]) ml/min/1.73 m(2) ) with cyclosporine, a difference of 10.5 ml/min/1.73 m(2) in favour of everolimus (P < 0.001). From randomization to month 12, adjusted estimated GFR increased by a mean of 9.8 (95% CI [6.2, 13.4]) ml/min/1.73 m(2) with everolimus versus -0.7 (95% CI [-4.6, 3.1]) ml/min/1.73 m(2) ) (P < 0.001) with cyclosporine. There were six biopsy-proven acute rejection episodes in everolimus-treated patients (five Banff grade I) and one episode in cyclosporine-treated patients (Banff grade 1). Overall safety profile was similar between groups. Discontinuation due to adverse events occurred in three everolimus patients (7.1%) and five cyclosporine patients (13.2%) between randomization and month 12. Initiation of everolimus with early elimination of calcineurin therapy is associated with a significant renal benefit at 12 months post-transplant that is observed in both living and deceased-donor recipients. (clinicaltrials.gov NCT00154310).

Influence of renal function on long-term graft survival and patient survival in renal transplant recipients

OBJECTIVES

Renal function post kidney transplantation is an outcome of interest for both clinicians and regulators evaluating immunosuppressive treatments post-transplantation. The current review sought to provide a synopsis of currently available literature examining the relationship between post-transplantation renal function and long-term graft survival and patient survival.

METHODS

A systematic literature review was performed using the PubMed, EMBASE and Cochrane Library databases. The search strategy was designed based on high level Medical Subject Heading (MeSH) terms and designed to capture studies published in English to 2012 and identified a total of 2683 unique hits; for inclusion studies were required to have >100 patients. Following two rounds of screening, a total of 27 studies were included in the final review (26 of which were identified via the literature review and one study was identified via searches of the reference sections of included studies).

RESULTS

The consensus among studies was that lower post-transplantation GFR, in particular 12 month GFR, was consistently and significantly associated with an increased risk for overall graft loss, death-censored graft loss and all-cause mortality in both univariate and multivariate analyses. The magnitude of the association between reduced GFR and outcomes was greater for death-censored graft loss versus overall graft loss and for graft loss in comparison with overall patient mortality. The predictive utility of GFR alone in predicting long-term outcomes was reported to be limited.

CONCLUSIONS

Lower GFR and greater rates of decline in GFR post-transplantation are associated with an increased risk for graft loss (overall and death-censored) and all-cause mortality; however, the predictive utility of GFR alone in predicting long-term outcomes is limited.

Kidney transplantation outcomes from expanded criteria donors, standard criteria donors or living donors older than 60 years

OBJECTIVES

To evaluate outcomes in kidney allograft recipients from donors with expanded criteria (ECD) versus standard criteria (SCD) or living donors (LD) >60 years.

METHODS

We studied all patients who received a kidney between 2005 and 2011, focusing in recipients of kidneys from deceased ECD, SCD and LD >60 years. ECD was any deceased donor >60 years or >50 years with two of the following: hypertension (HTN), stroke as the cause of death, or serum creatinine >1.5 mg/dL. We recorded characteristics of the transplant procedure, patient, graft survival and renal function 1 year after transplantation and at the end of follow-up.

RESULTS

Six-hundred and five patients were transplanted between 2005 and 2011 in our department. There were 142 (25.1%) transplantations from ECD, 192 (33.98%) from SCD and 96 (16.99%) from LDs older than 60 years. In a mean follow-up time of 36.4 months, graft survival rates were similar for all groups. Calculated GFR was found statistically different between the ECD and SCD groups, but still satisfactory at first year, and at end of follow-up time. Comparison of the patients, who received transplants from ECD, even older than 70 years, and those from LD >60 years revealed equivalent renal function in short and long term.

CONCLUSIONS

Utilization of marginal kidneys effectively doubled our deceased transplant volume in the period 2005-2011. Patients' and graft survival were shown similar at the end of follow-up for all groups. Renal outcomes were shown equivalent between the ECD and LD >60 years groups, and although significantly lower between the ECD and the SCD group, were still very satisfactory.

Calcineurin inhibitor nephrotoxicity: a review and perspective of the evidence

BACKGROUND

There is no doubt that acute calcineurin inhibitor (CNI) nephrotoxicity exists; however, chronic CNI nephrotoxicity is questionable at best.

METHODS

We reviewed the literature to identify original articles related to the use of CNIs in renal and nonrenal solid organ transplantation in order to examine the available evidence about their chronic nephrotoxicity and contribution to graft failure.

RESULTS

Early clinical experience and animal studies support the evidence of CNI nephrotoxicity. These findings evolved into the dogma that CNI nephrotoxicity is the major cause of late renal allograft failure. However, in transplanted kidneys the specific role of chronic CNI nephrotoxicity has been questioned. The emerging literature clearly highlights the lack of solid evidence for the role of CNIs as the sole and major injurious agents that cause chronic renal dysfunction and subsequent graft failure. Most of the evidence available to date is against complete CNI avoidance, and minimization appears to be a more viable strategy. It is becoming increasingly clear that the typical pathological lesions linked to chronic CNI use are highly nonspecific, and most of the chronic changes that have been attributed to chronic CNI nephrotoxicity are the consequences of previously unrecognized immunologic injuries. One needs to keep in mind that the potential risk of side effects of CNI use should be balanced against the risk of rejection.

CONCLUSIONS

More research should focus on addressing the true causes of chronic graft dysfunction rather than focusing on the overexaggerated contribution of CNIs to late graft loss.

Long-term impact of hypertension on renal allografts

OBJECTIVE

We assessed the impact of hypertension on renal transplant function and survival in the past decade after introduction of mycophenolate mofetil and rituximab.

METHODS

We examined the 184 patients who underwent renal transplantation from March 1982 to September 1999 and presented at our outpatient clinic from 2001 to 2011. They were divided into group 1 with mean systolic blood pressure (mSBP) >130 mm Hg and Group 2 with mSBP <130 mm Hg. We compared mean serum creatinine (sCr) levels for 9 years and 12-year actuarial graft survival rates. Risk factors for graft survival were assessed by Cox regression analysis.

RESULTS

There were 75 group 1 and 109 group 2 recipients. The mean sCr level of group 1 was 1.59 ± 0.12 mg/dL and that of group 2 1.54 ± 0.10 mg/dL (P < .0001). Of note was that mean sCr levels of group 1 started to increase about 3 years after transplantation. Although 5-year graft survival rates of both groups were 100%, 9- and 12-year rates among group 1 were 97.3% and 90.5%, respectively, whereas among group 2 they were 99.1% and 98.1%, respectively (P = .0195). Cox univariate and multivariate analyses showed mean SBP to be the only significant risk factor for graft survival (P < .05).

CONCLUSIONS

We concluded that the hypertensive group showed deteriorating renal function from around 3 years after transplantation that lowered graft survival afterward, resulting in a clear distinction from the nonhypertensive group at around 10 years after transplantation. Mean SBP was a significant risk factor for graft survival. Hypertension may be a surrogate for a poor renal graft prognosis in the long run.

Three-year outcomes from BENEFIT, a randomized, active-controlled, parallel-group study in adult kidney transplant recipients

The clinical profile of belatacept in kidney transplant recipients was evaluated to determine if earlier results in the BENEFIT study were sustained at 3 years. BENEFIT is a randomized 3 year, phase III study in adults receiving a kidney transplant from a living or standard criteria deceased donor. Patients were randomized to a more (MI) or less intensive (LI) regimen of belatacept, or cyclosporine. 471/666 patients completed ≥3 years of therapy. A total of 92% (MI), 92% (LI), and 89% (cyclosporine) of patients survived with a functioning graft. The mean calculated GFR (cGFR) was ∼21 mL/min/1.73 m(2) higher in the belatacept groups versus cyclosporine at year 3. From month 3 to month 36, the mean cGFR increased in the belatacept groups by +1.0 mL/min/1.73 m(2) /year (MI) and +1.2 mL/min/1.73 m(2) /year (LI) versus a decline of -2.0 mL/min/1.73 m(2) /year (cyclosporine). One cyclosporine-treated patient experienced acute rejection between year 2 and year 3. There were no new safety signals and no new posttransplant lymphoproliferative disorder (PTLD) cases after month 18. Belatacept-treated patients maintained a high rate of patient and graft survival that was comparable to cyclosporine-treated patients, despite an early increased occurrence of acute rejection and PTLD.

Renal function following living, standard criteria deceased and expanded criteria deceased donor kidney transplantation: impact on graft failure and death

We examined United States Renal Data System (USRDS) data for adult kidney transplant recipients in 1995-2003 (n = 87 575) to investigate associations of 12-month renal function with long-term clinical outcomes. Estimated glomerular filtration rate (eGFR) was computed by the Modification of Diet in Renal Disease (MDRD) equation. Associations of eGFR at the first transplant anniversary with graft and patient-survival in years 1-9 post-transplant were evaluated by multivariate nonlinear regression with spline forms, adjusted for recipient, donor, and transplant factors. Regardless of donor type, the likelihood of graft failure and death increased significantly with lower eGFR. The impact of poor eGFR was more pronounced for graft failure than death. Relative effects were similar across donor types, but were strongest among living-donor recipients. For example, compared with reference eGFR of 80 ml/min/1.73 m2, 1-year eGFR of 20 ml/min/1.73 m2 was associated with adjusted hazards ratios for subsequent death-censored graft failure of 9.2 in living, 8.9 in standard criteria deceased, and 5.9 in expanded criteria deceased-donor recipients. First-year renal function after kidney transplantation has strong, nonlinear associations with subsequent allograft and patient survival regardless of donor type. Post-transplant eGFR may be a useful end-point for discriminating benefits of care strategies that differentially affect renal function.

Can the nephron be spared?

The search continues for the best role for mTOR inhibitor drugs in renal transplantation-principally to avoid or minimize the nephrotoxicity of the CNI class of immunosuppressive agents. The Spare the Nephron Trial describes the popular approach of early conversion from a CNI to the mTOR agent sirolimus for patients maintained on mycophenolate mofetil and steroids. At 1-2 years the glomerular filtration rate (GFR) was superior for the sirolimus group, with a loss of tolerability for about 20%.