Very Low-Grade Proteinuria at 3 Months Posttransplantation Is an Earlier Marker of Graft Survival

Temporal changes of proteinuria after kidney transplantation: association with cardiovascular morbidity and mortality

BACKGROUND

Proteinuria is common in kidney transplant recipients and has been established as a risk factor for graft-loss and mortality. In the general population, proteinuria has also been tied to a higher risk of cardiovascular disease. There is limited data exploring the association between changes in proteinuria over time and cardiovascular disease in kidney transplant recipients.

METHODS

In this retrospective cohort study we evaluated proteinuria as a time-varying covariate using urine dipstick protein values at 6 month intervals post-transplant. The primary outcome was the occurrence a major cardiovascular event (MACE). Univariate and multivariate time varying Cox model was used.

RESULTS

579 patients were included in the final cohort. 120 episodes of MACE were documented in 98 patients. Time varying proteinuria was associated with MACE by univariate and multivariate analysis (HR 2.63, 95% CI 1.76-3.93, p < 0.001) and (HR 2.33, 95% CI 1.53-3.54, p < 0.001). Reduction of proteinuria to normal was associated with reduced risk of MACE compared with active proteinuria (HR 0.44, 95% CI 0.28-0.69, p < 0.001) and (HR 0.47, 95% CI 0.3-0.76, p = 0.002) for univariate and multivariate analyses. Exposure to proteinuria for more than 1 year was significantly associated with an increased risk of MACE for univariate and multivariate analysis (HR 2.33, 95% CI 1.48-3.68, p < 0.001) and (HR 2.18, 95% CI 1.37-3.45, p = 0.002) respectively, in comparison to exposure of less than 1 year.

CONCLUSION

These findings may suggest that we should consider applying clinical interventions that are known to reduce cardiovascular morbidity in these patients.

Relationship between early proteinuria and long term outcome of kidney transplanted patients from different decades of donor age

Background

Proteinuria after kidney transplantation portends a worse graft survival. However the magnitude of proteinuria related to patient and graft survival and its correlation with donor and recipient characteristics are poorly explored.

Methods

This study investigated the impact of post transplant proteinuria in the first year in 1127 kidney transplants analyzing the impact of different donor ages. Proteinuria cut off was set at 0.5 g/day.

Results

Transplants with proteinuria > 0.5 g/day correlated with poor graft and patient outcome in all donor age groups. In addition, 6-month-1-year proteinuria increase was significantly associated with graft outcome, especially with donors > 60 years old (p <  0.05; Odd Ratio 1.8). 1-year graft function (eGFR < or ≥ 44 ml/min) had similar impact to proteinuria (≥ 0.5 g/day) on graft failure (Hazard Ratio 2.77 vs Hazard Ratio 2.46). Low-grade proteinuria (0.2–0.5 g/day) demonstrated a trend for worse graft survival with increasing donor age. Also in kidney-paired analysis proteinuria ≥0.5 effect was more significant with donors > 50 years old (Odd Ratio 2.3).

Conclusions

Post-transplant proteinuria was increasingly harmful with older donor age. Proteinuria ≥0.5 g/day correlates with worse outcomes in all transplanted patients. Prognostic value of proteinuria and eGFR for graft and patient survival was comparable and these two variables remain significant risk factors even in a multivariate model that take into consideration the most important clinical variables (donor age, rejection, delayed graft function and cytomegalovirus viremia among others).

The Risk Factors of mTORi-Associated Posttransplant Proteinuria

Treatment with mammalian target of rapamycin inhibitors (mTORi) has been associated with an increased incidence of proteinuria after kidney transplantation as compared to other immunosuppressive agents. Proteinuria after mTORi use may occur in different clinical conditions and the precise mechanism remains unclear. The objective of this study was to investigate the related risk factors for proteinuria after mTORi treatment in kidney transplant recipients. This retrospective observational study population consisted of kidney transplant recipients followed up in a medical center in Southern Taiwan from January 1999 to April 2016. The baseline characteristics and transplantation-related profiles were collected at the time of enrollment. We examined risk factors for mTORi-associated proteinuria using a multivariate logistic regression analysis. P < .05 was considered as statistically significant. Hyperlipidemia and obesity at the initiation of mTORi treatment were strong predictors for proteinuria. Earlier identification of these risk factors may assist physicians in deciding the best candidate for mTORi conversion in order to optimize transplantation outcomes.

Efficacy and Safety of Everolimus for Maintenance Immunosuppression of Kidney Transplantation: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Conversion to everolimus is often used in kidney transplantation to overcome calcineurin inhibitor (CNI) nephrotoxicity but there is conflicting evidence for this approach.

OBJECTIVES

To investigate the benefits and harm from randomized clinical trials (RCTs) involving the conversion from CNI to everolimus after kidney transplantation.

METHODS

Databases were searched up to March 2016. Two reviewers independently assessed trials for eligibility and quality, and extracted data. Results are expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

RESULTS

Eleven RCTs, with a total of 1,633 patients, met the final inclusion criteria. Patients converted to everolimus had improved renal function at 1 year posttransplant with an estimated glomerular filtration rate (eGFR) of 5.36 mL/min per 1.73 m2 greater than patients remaining on CNI (p = 0.0005) and the longer-term results (> 1 year) of renal function was identical to that of 1 year. There was not a substantial difference in graft loss, mortality, and the occurrence of adverse events (AEs) or serious AEs. However, the risks of acute rejection and trial termination due to AEs with everolimus are respectively 1.82 and 2.63 times greater than patients staying on CNI at 1 year posttransplant (p = 0.02, p = 0.03, respectively). Further, those patients who converted to everolimus had a substantially greater risk of anemia, hyperlipidemia, hypercholesterolemia, hypokalemia, proteinuria, stomatitis, mouth ulceration, and acne.

CONCLUSIONS

Conversion from CNI to everolimus after kidney transplantation is associated with improved renal function in the first 5 years posttransplant but increases the risk of acute rejection at 1 year posttransplant and may not be well endured.

Progression of urinary protein excretion after kidney transplantation: A marker for poor long-term prognosis

INTRODUCTION

Post-transplantation proteinuria is a risk factor for graft failure. A progressive decline in renal graft function is a predictor for mortality in kidney transplant patients.

OBJECTIVES

To assess the development and the progression of urinary protein excretion (UPE) in the first year post-transplant in recipients of kidney transplants and its effect on patient and graft outcomes.

MATERIALS AND METHODS

We analysed 1815 patients with 24-h UPE measurements available at 3 and 12 months post-transplant. Patients were divided based on their UPE level: below 300 mg, 300-1000 mg and over 1000 mg (at 3 and 12 months), and changes over time were analysed.

RESULTS

At 3 months, 65.7% had UPE below 300 mg/24 h, 29.6% 300-1000 mg/24 h and 4.7% over 1000 mg/24h. At one year, 71.6% had UPE below 300 mg/24 h, 24.1% 300-1000 mg/24 h and 4.4% over 1000 mg/24 h. In 208 patients (12%), the UPE progressed, in 1233 (70.5%) it remained stable and in 306 (17.5%) an improvement was observed. We found that the level of UPE influenced graft survival, particularly if a progression occurred. Recipient's age and renal function at one year were found to be predictive factors for mortality, while proteinuria and renal function were predictive factors for graft survival.

CONCLUSIONS

Proteinuria after transplantation, essentially when it progresses, is a marker of a poor prognosis and a predictor for graft survival. Progression of proteinuria is associated with poorer renal function and lower graft survival rates.

The effect of everolimus versus mycophenolate upon proteinuria following kidney transplant and relationship to graft outcomes

Although mTOR inhibitor use has been associated with proteinuria in kidney transplant recipients, dose dependency and impact on allograft function are unknown. In a post hoc analysis, we compared rates of proteinuria 3 months posttransplant among everolimus (EVR) and mycophenolate (MPA) treatment arms and used a time-dependent model to correlate the risk of proteinuria to EVR trough levels up to 24 months posttransplant. eGFR and graft loss was compared by proteinuria status at 3 months. Of 833 randomized patients, 24%, 36% and 19% of lower exposure EVR (1.5 mg/day), higher exposure EVR (3.0 mg/day) and MPA-treated patients had proteinuria ≥ 300 mg/g Cr at 3 months, respectively. EVR 1.5 was not associated with an increase in risk of proteinuria (HR 1.20; p = 0.19) unlike EVR 3.0 (HR 1.84; p < 0.001) versus MPA. EVR trough levels >8 ng/mL were significantly associated with proteinuria compared to 3-8 ng/mL (HR 1.86; p < 0.001). Those patients with proteinuria at 3 months and those who developed proteinuria thereafter had lower eGFR and higher graft loss at 24 months, regardless of treatment arm. We identify a dose-dependent effect of EVR with the risk of proteinuria; however, its independent impact upon eGFR and graft survival at 2 years was not evident.

Conversion of long-term kidney transplant recipients from calcineurin inhibitor therapy to everolimus: a randomized, multicenter, 24-month study

BACKGROUND

Benefits of conversion from calcineurin inhibitor (CNI) to mammalian target of rapamycin inhibitor-based immunosuppression in long-term kidney transplant patients remain uncertain.

METHODS

ASCERTAIN was a 24-month, open-label, multicenter study. Kidney transplant patients more than 6 months posttransplant receiving CNI (baseline glomerular filtration rate [GFR] 30-70 mL/min/1.73 m) were randomized to everolimus with CNI elimination (n=127) or CNI minimization (n=144), or continued CNI unchanged (controls, n=123) to assess the effect on measured GFR at month 24 after randomization.

RESULTS

Renal function was stable in all groups to month 24. Mean measured GFR at month 24, the primary endpoint, was 48.0±22.0 mL/min/1.73 m, 46.6±21.1 mL/min/1.73 m, and 46.0±20.4 mL/min/1.73 m in the CNI elimination, CNI minimization, and control groups, respectively. Differences between CNI elimination (1.12 mL/min/1.73 m, 95% confidence interval [CI] -3.51 to 5.76, P=0.63) and CNI minimization (0.59 mL/min/1.73 m, 95% CI -3.88 to 5.07, P=0.79) versus controls at month 24 were nonsignificant that is, the primary endpoint was not met. No efficacy endpoint differed significantly between groups. Post hoc analyses showed that patients with baseline creatinine clearance (CrCl) more than 50 mL/min had a significantly greater increase in measured GFR after CNI elimination versus controls (difference 11.4 mL/min/1.73 m, 95% CI 2.1 to 20.8 mL/min/1.73 m, P=0.017). Adverse events resulted in discontinuation in 36 (28.3%) CNI elimination patients, 24 (16.7%) CNI minimization patients, and 5 (4.1%) controls (P<0.001 vs. CNI elimination; P=0.020 vs. CNI minimization).

CONCLUSION

Conversion to everolimus with CNI elimination or minimization a mean of 5.6 years after kidney transplantation had no overall renal benefit and was associated with more frequent adverse events and discontinuations. Patients with CrCl more than 50 mL/min may benefit from a change in therapy more than 6 months after renal transplantation.