Estimation of glomerular filtration rates before and after orthotopic liver transplantation: evaluation of current equations

Novel indications for referral and care for simultaneous liver kidney transplant recipients

PURPOSE OF REVIEW

Kidney dysfunction is challenging in liver transplant candidates to determine whether it is reversible or not. This review focuses on the pertinent data on how to best approach liver transplant candidates with kidney dysfunction in the current era after implementing the simultaneous liver kidney (SLK) allocation policy and safety net.

RECENT FINDINGS

The implementation of the SLK policy inverted the steady rise in SLK transplants and improved the utilization of high-quality kidneys. Access to kidney transplantation following liver transplant alone (LTA) increased with favorable outcomes. Estimating GFR in liver transplant candidates remains challenging, and innovative methods are needed. SLK provided superior patient and graft survival compared to LTA only for patients with advanced CKD and dialysis at least 3 months. SLK can provide immunological protection against kidney rejection in highly sensitized candidates. Post-SLK transplant care is complex, with an increased risk of complications and hospitalization.

SUMMARY

The SLK policy improved kidney access and utilization. Transplant centers are encouraged, under the safety net, to reserve SLK for liver transplant candidates with advanced CKD or dialysis at least 3 months while allowing lower thresholds for highly sensitized patients. Herein, we propose a practical approach to liver transplant candidates with kidney dysfunction.

Essentials of Liver Transplantation in the Setting of Acute Kidney Injury and Chronic Kidney Disease

Kidney dysfunction is common among liver transplant candidates with decompensated cirrhosis and has a major impact on pre- and post-liver transplant survival. Updated definitions of acute kidney injury and criteria for the diagnosis of hepatorenal syndrome allow for early recognition and intervention, including early initiation of vasoconstrictor therapy for hepatorenal syndrome. The rise of the metabolic syndrome and nonalcoholic fatty liver disease as a cause of cirrhosis has coincided with an increase in intrinsic chronic kidney disease recognized in transplant candidates and recipients. Ultimately, the ability to accurately assess kidney function and associated risk is essential to decision-making in the context of transplantation, including selection of candidates for simultaneous liver and kidney transplantation.

Impact of race-independent equations on estimating glomerular filtration rate for the assessment of kidney dysfunction in liver disease

BACKGROUND

Altered hemodynamics in liver disease often results in overestimation of glomerular filtration rate (GFR) by creatinine-based GFR estimating (eGFR) equations. Recently, we have validated a novel eGFR equation based on serum myo-inositol, valine, and creatinine quantified by nuclear magnetic resonance spectroscopy in combination with cystatin C, age and sex (GFR_NMR). We hypothesized that GFR_NMR could improve chronic kidney disease (CKD) classification in the setting of liver disease.

RESULTS

We conducted a retrospective multicenter study in 205 patients with chronic liver disease (CLD), comparing the performance of GFR_NMR to that of validated CKD-EPI eGFR equations, including eGFRcr (based on creatinine) and eGFRcr-cys (based on both creatinine and cystatin C), using measured GFR as reference standard. GFR_NMR outperformed all other equations with a low overall median bias (-1 vs. -6 to 4 ml/min/1.73 m² for the other equations; p < 0.05) and the lowest difference in bias between reduced and preserved liver function (-3 vs. -16 to -8 ml/min/1.73 m² for other equations). Concordant classification by CKD stage was highest for GFR_NMR (59% vs. 48% to 53%) and less biased in estimating CKD severity compared to the other equations. GFR_NMR P30 accuracy (83%) was higher than that of eGFRcr (75%; p = 0.019) and comparable to that of eGFRcr-cys (86%; p = 0.578).

CONCLUSIONS

Addition of myo-inositol and valine to creatinine and cystatin C in GFR_NMR further improved GFR estimation in CLD patients and accurately stratified liver disease patients into CKD stages.

The impact of long-term exposure to tacrolimus on chronic kidney disease after lung transplantation: A retrospective analysis from a single transplantation center

BACKGROUND

Chronic kidney disease (CKD) is a progressive and irreversible complication in lung transplant patients who have received long-term treatment with tacrolimus. This study aimed to verify long-term tacrolimus exposure values in CKD progression.

METHODS

We retrospectively analyzed the clinical data of adult lung transplant recipients performed at our center between 2012 and October 2015. Patients who completed the 5-year follow-up period were enrolled in this study. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m².

RESULTS

Eighty patients were analyzed. Compared with baseline (109 ± 38.1 mL/min/1.73 m2), the average eGFR values of our patients gradually decreased during the fifth-year post transplantation (46.5%, 58.3 ± 28.3 mL/min/1.73 m2), and the decline in eGFR values was particularly pronounced in the first year (31.2%, 74.6 ± 28.91 mL/min/1.73 m2). Moreover, 10 (12.7%), 21 (26.9%), 24 (31.2%), 28 (41.2%), and 48 (60%) patients had eGFR <60 mL/min/1.73 m² at 3, 6, 1, 3, and 5 years after lung transplantation (LT), respectively. A significant negative correlation was found between tacrolimus dose and eGFR 6 months after LT (P = 0.0414). We found no correlation between the serum tacrolimus concentration and CKD progression.

CONCLUSION

eGFR constantly decreased and the incidence of CKD increased during the 5-year follow-up period after LT. The tacrolimus dose had a significant negative correlation with eGFR at 6 months after LT. Meanwhile, whole-blood tacrolimus trough concentrations were not correlated with eGFR decline. When possible, lower dosing within 1 year after LT can reduce potential nephrotoxic side effects.

Assessment of glomerular filtration rate in patients with cirrhosis: Available tools and perspectives

Renal dysfunction often complicates the course of liver disease, resulting in higher morbidity and mortality. The accurate assessment of kidney function in these patients is essential to early identify, stage and treat renal impairment as well as to better predict the prognosis, prioritize the patients for liver transplantation and decide whether to opt for simultaneous liver-kidney transplants. This review analyses the available tools for direct or indirect assessment of glomerular filtration rate, focusing on the flaws and strengths of each method in the specific setting of cirrhosis. The aim is to deliver a clear-cut view on this complex issue, trying to point out which strategies to prefer in this context, especially in the peculiar setting of liver transplantation. Moreover, a glance is given at future promising tools for glomerular filtration rate assessment, including new biomarkers and new equations specifically modelled for the cirrhotic population.

Kidney Disease after Heart and Lung Transplantation

Chronic kidney disease (CKD) is not only common after lung and heart transplantation but also is associated with increased morbidity and mortality due to multiple pre-, peri- and post-transplant factors. While the exact incidence of CKD in this population is not well-defined, it seems to have gradually increased over the years as older recipients are more frequently considered. The increasing success of the procedure and expanding transplant candidate pool has allowed many with comorbid conditions to receive a transplant, which was considered prohibitive in the past. This review presents risk factors that have been linked to CKD as well as interventions that may help alleviate this serious problem. The impact of pretransplant renal function and the overexaggerated role of chronic nephrotoxicity of calcineurin inhibitors is discussed in detail. Until the exact pathophysiology of kidney disease is better understood, there is a dire need to expand the research agenda beyond observational studies.

Kidney disease in non-kidney solid organ transplantation

Kidney disease after non-kidney solid organ transplantation (NKSOT) is a common post-transplant complication associated with deleterious outcomes. Kidney disease, both acute kidney injury and chronic kidney disease (CKD) alike, emanates from multifactorial, summative pre-, peri- and post-transplant events. Several factors leading to kidney disease are shared amongst solid organ transplantation in addition to distinct mechanisms unique to individual transplant types. The aim of this review is to summarize the current literature describing kidney disease in NKSOT. We conducted a narrative review of pertinent studies on the subject, limiting our search to full text studies in the English language. Kidney disease after NKSOT is prevalent, particularly in intestinal and lung transplantation. Management strategies in the peri-operative and post-transplant periods including proteinuria management, calcineurin-inhibitor minimization/ sparing approaches, and nephrology referral can counteract CKD progression and/or aid in subsequent kidney after solid organ transplantation. Kidney disease after NKSOT is an important consideration in organ allocation practices, ethics of transplantation. Kidney disease after SOT is an incipient condition demanding further inquiry. While some truths have been revealed about this chronic disease, as we have aimed to describe in this review, continued multidisciplinary efforts are needed more than ever to combat this threat to patient and allograft survival.

Renal function after liver transplantation: Real-world experience with basiliximab induction and delayed reduced-dose tacrolimus

BACKGROUND

Routine use of delayed reduced-dose calcineurin-inhibitor treatment with induction immunosuppression in liver transplantation to minimize post-operative kidney injury is still scarce.

AIM

To evaluate real-world experience of basiliximab induction with delayed reduced-dose tacrolimus.

METHODS

In a retrospective cohort study, kidney function was evaluated pre- and postoperatively by measured glomerular filtration rate (mGFR). Adult patients undergoing liver transplantation between 2000 and 2017 were divided into a conventional treatment group (immediate-introduction of tacrolimus, target trough levels 10-15 ng/mL, and corticosteroids, n = 203) and a revised treatment group (basiliximab induction, reduced-dose tacrolimus, target through levels 5-8 ng/mL, delayed until day three, and mycophenolate mofetil 2000 mg/day, n = 343).

RESULTS

Mean mGFR was similar between groups at wait-listing (85.3 vs 84.1 ml/min/1.73m², p = 0.60), but higher in the revised treatment group at 3 (56.8 vs 63.4 ml/min/1.73m², p = 0.004) and 12 months post-transplant (60.9 vs 69.7 ml/min/1.73m², p<0.001); this difference remained after correcting for multiple confounders and was independent of pre-transplant mGFR. In the revised treatment group, biopsy proven acute rejection rate was lower (38% vs. 21%, p<0.001), and graft-survival better (p = 0.01).

CONCLUSION

Basiliximab induction with delayed reduced-dose tacrolimus is associated with less kidney injury when compared to standard-dose tacrolimus, without increased risk of rejection, graft loss or death.

Race Adjustment in eGFR Equations Does Not Improve Estimation of Acute Kidney Injury Events in Patients with Cirrhosis

BACKGROUND

Accuracy of glomerular filtration rate estimating (eGFR) equations has significant implications in cirrhosis, potentially guiding simultaneous liver kidney allocation and drug dosing. Most equations adjust for Black race, partially accounted for by reported differences in muscle mass by race. Patients with cirrhosis, however, are prone to sarcopenia which may mitigate such differences. We evaluated the association between baseline eGFR and incident acute kidney injury (AKI) in patients with cirrhosis with and without race adjustment.

METHODS

We conducted a retrospective national cohort study of veterans with cirrhosis. Baseline eGFR was calculated using multiple eGFR equations including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), both with and without race adjustment. Poisson regression was used to investigate the association between baseline eGFR and incident AKI events per International Club of Ascites criteria.

RESULTS

We identified 72,267 patients with cirrhosis, who were 97.3% male, 57.8% white, and 19.7% Black. Over median follow-up 2.78 years (interquartile range 1.22-5.16), lower baseline eGFR by CKD-EPI was significantly associated with higher rates of AKI in adjusted models. For all equations this association was minimally impacted when race adjustment was removed. For example, removal of race adjustment from CKD-EPI resulted in a 0.1% increase in the association between lower eGFR and higher rate of AKI events per 15 mL/min/1.73 m² change (p < 0.001).

CONCLUSIONS

Race adjustment in eGFR equations did not enhance AKI risk estimation in patients with cirrhosis. Further study is warranted to assess the impacts of removing race from eGFR equations on clinical outcomes and policy.

Estimated glomerular filtration rate by formulas in patients with cirrhosis: An unreliable procedure

BACKGROUND & AIMS

In cirrhosis, the reliability of formulas that estimate renal function, either those specifically developed in this population or the classic equations, has not been properly quantified. We studied the agreement between estimated (eGFR) and measured glomerular filtration rate (mGFR) in cirrhosis.

METHODS

Renal function was estimated with 56 formulas including specific equations: Glomerular Filtration Rate Assessment in Liver Disease (GRAIL), Royal Free Hospital Cirrhosis (RFHC) and Mindikoglu-eGFR, and measured with a gold standard procedure; plasma clearance of iohexol using dried blood spots sampling in a group of cirrhotics. The agreement eGFR-mGFR was evaluated with specific tests: total deviation index (TDI), concordance correlation coefficient (CCC) and coverage probability (CP). We defined acceptable agreement as values: TDI < 10%, CCC ≥ 0.9 and CP > 90%.

RESULTS

A total of 146 patients (age 65 ± 9 years, 81% male) were evaluated; 61 (42%) Child A, 67 (46%) Child B and 18 (12%) Child C. Median MELD-Na was 14 (9-15). The agreement between eGFR and mGFR was poor: TDI averaged was of 73% (90% of the estimations ranged from ±73% of mGFR); CCC averaged was 0.7 indicating low concordance and CP averaged 22% indicating that 78% of the estimations have an error > 10%. Specific formulas showed also poor agreement: TDI was 82%, 70% and 37% for the GRAIL, RFHC and Mindikoglu equations, respectively.

CONCLUSIONS

Overall, formulas poorly estimated renal function in cirrhotic patients. Specific formulas designed for cirrhosis did not outperform classic equations. eGFR must be considered with caution in cirrhotic patients.

The changing impact of pre-liver transplant renal dysfunction on post-transplant survival: results of 2 decades from a single center

INTRODUCTION AND OBJECTIVES

Renal dysfunction before liver transplantation (LT) is associated with higher post-LT mortality. We aimed to study if this association still persisted in the contemporary transplant era.

MATERIALS AND METHODS

We retrospectively reviewed data on 2871 primary LT performed at our center from 1998 to 2018. All patients were listed for LT alone and were not considered to be simultaneous liver-kidney (SLK) transplant candidates. SLK recipients and those with previous LT were excluded. Patients were grouped into 4 eras: era-1 (1998-2002, n = 488), era-2 (2003-2007, n = 889), era-3 (2008-2012, n = 703) and era-4 (2013-2018, n = 791). Pre-LT renal dysfunction was defined as creatinine (Cr) >1.5 mg/dl or on dialysis at LT. The effect of pre-LT renal dysfunction on post-LT patient survival in each era was examined using Kaplan Meier estimates and univariate and multivariate Cox proportional hazard analyses.

RESULTS

Pre-LT renal dysfunction was present in 594 (20%) recipients. Compared to patients in era-1, patients in era-4 had higher Cr, lower eGFR and were more likely to be on dialysis at LT (P < 0.001). Pre-LT renal dysfunction was associated with worse 1, 3 and 5-year survival in era-1 and era-2 (P < 0.005) but not in era-3 or era-4 (P = 0.13 and P = 0.08, respectively). Multivariate analysis demonstrated the lack of independent effect of pre-LT renal dysfunction on post-LT mortality in era-3 and era-4. A separate analysis using eGFR <60 mL/min/1.73 m² at LT to define renal dysfunction showed similar results.

CONCLUSIONS

Pre-LT renal dysfunction had less impact on post-LT survival in the contemporary transplant era.

Prediction of chronic kidney disease after orthotopic liver transplantation: development and validation of a nomogram model

BACKGROUND

We aimed to develop and validate a nomogram model for predicting CKD after orthotopic liver transplantation (OLT).

METHODS

The retrospective data of 399 patients who underwent transplantation and were followed in our centre were collected. They were randomly assigned to the training set (n = 293) and validation set (n = 106). Multivariable Cox regression analysis was performed in the training set to identify predictors of CKD. According to the Cox regression analysis results, a nomogram model was developed and validated. The renal function of recipients was monitored, and the long-term survival prognosis was assessed.

RESULTS

The incidence of CKD at 5 years after OLT was 25.6%. Cox regression analysis identified several predictors of post-OLT CKD, including recipient age at surgery (HR 1.036, 95% CI 1.006-1.068; p = 0.018), female sex (HR 2.867, 95% CI 1.709-4.810; p < 0.001), preoperative hypertension (HR 1.670, 95% CI 0.962-2.898; p = 0.068), preoperative eGFR (HR 0.996, 95% CI 0.991-1.001; p = 0.143), uric acid at 3 months (HR 1.002, 95% CI 1.001-1.004; p = 0.028), haemoglobin at 3 months (HR 0.970, 95% CI 0.956-0.983; p < 0.001), and average concentration of cyclosporine A at 3 months (HR 1.002, 95% CI 1.001-1.003; p < 0.001). According to these parameters, a nomogram model for predicting CKD after OLT was constructed and validated. The C-indices were 0.75 and 0.80 in the training and validation sets. The calibration curve of the nomogram showed that the CKD probabilities predicted by the nomogram agreed with the observed probabilities at 1, 3, and 5 years after OLT (p > 0.05). Renal function declined slowly year by year, and there were significant differences between patients divided by these predictors. Kaplan-Meier survival analysis showed that the survival prognosis of recipients decreased significantly with the progression of renal function.

CONCLUSIONS

With excellent predictive abilities, the nomogram may be a simple and reliable tool to identify patients at high risk for CKD and poor long-term prognosis after OLT.

CKD in Recipients of Nonkidney Solid Organ Transplants: A Review

Chronic kidney disease (CKD) after solid organ transplant is a common clinical presentation, affecting 10% to 20% of liver, heart and lung transplant recipients and accounting for approximately 5% of the kidney transplant waiting list. The causes of CKD are different for different types of transplants and are not all, or even predominantly, due to calcineurin inhibitor toxicity, with significant heterogeneity particularly in liver transplant recipients. Many solid organ transplant recipients with advanced CKD benefit from kidney transplantation, but have a higher rate of death while waitlisted and higher mortality following transplant than the general kidney failure population. Recent organ allocation policies and proposals have attempted to address the appropriate identification and prioritization of candidates in need of a kidney transplant, either simultaneous with or following non-kidney transplant. Future research should focus on predictive factors for individuals identified at high risk for progression to kidney failure and death, and strategies to preserve kidney function and minimize the CKD burden in this unique patient population.

Post-liver transplantation chronic kidney disease is associated with increased cardiovascular disease risk and poor survival

Chronic kidney disease (CKD) is common following liver transplantation (LT). We aimed to investigate the frequency, risk factors, and impact of CKD on cardiovascular disease (CVD), graft, and patient survival. We analyzed 752 patients who received LT at the University of Alberta. Development of CKD was defined as eGFR <60 ml/min for greater than 3 months, intrinsic renal disease or presence of end-stage renal disease requiring renal replacement therapy. 240 patients were female (32%), and mean age at LT was 53 ± 11 years. CKD was diagnosed in 448 (60%) patients. On multivariable analysis, age (OR 1.3; P = 0.01), female sex (OR 3.3; P < 0.001), baseline eGFR (OR 0.83; P < 0.001), MELD (OR 1.03; P = 0.01), de novo metabolic syndrome (OR 2.3; P = 0.001), and acute kidney injury (OR 3.5; P < 0.001) were associated with CKD. A higher tacrolimus concentration to dose ratio was protective for CKD (OR 0.69; P < 0.001). CKD was associated with post-transplant CVD (26% vs. 16% P < 0.001), reduced graft (HR 1.4; P = 0.02), and patient survival (HR 1.3; P = 0.03). CKD is a frequent complication following LT and is associated with an increased risk of CVD and reduced graft and patient survival.

Peritoneal Dialysis Use in Patients With Ascites: A Review

The past few decades have seen steady increase in the prevalence of kidney failure needing kidney replacement therapy. Concomitantly, there has been progressive growth of heart failure and chronic liver disease, and many such patients develop ascites. Therefore, it is not uncommon to encounter patients with kidney failure who concurrently have ascites. The presence of ascites adds many challenges in the management of kidney failure. Poor hemodynamics make volume management difficult. The presence of coagulopathy, malnutrition, and encephalopathy compounds the complexity of the management. Such patients do not tolerate hemodialysis well. However, several concerns have limited the use of peritoneal dialysis (PD), so hemodialysis remains the predominant dialysis modality in these patients. However, observational studies have illustrated that PD provides hemodynamic stability and facilitates better volume management compared with hemodialysis. Moreover, PD obviates the need for therapeutic paracentesis by facilitating continuous drainage of ascites. PD potentially reduces hemorrhagic complications by avoiding routine anticoagulation use. Moreover, small studies have suggested that outcomes such as peritonitis and mechanical complications are comparable to those in PD patients without ascites. PD does not affect transplant candidacy, and these patients can successfully receive combined liver and kidney transplants. Hence, PD should be considered a viable dialysis option in kidney failure patients with ascites.

Estimating Glomerular Filtration Rate in Cirrhosis Using Creatinine-Based and Cystatin C-Based Equations: Systematic Review and Meta-Analysis

Accurate estimation of kidney function in cirrhosis is crucial for prognosis and decisions regarding dual-organ transplantation. We performed a systematic review/meta-analysis to assess the performance of creatinine-based and cystatin C (CysC)-based eGFR equations compared with measured GFR (mGFR) in patients with cirrhosis. A total of 25 studies (n = 4565, 52.0 years, 37.0% women) comprising 18 equations met the inclusion criteria. In all GFR equations, the creatinine-based equations overestimated GFR (standardized mean difference, SMD, 0.51; 95% confidence interval [CI], 0.31-0.71) and CysC-based equations underestimated GFR (SMD, -0.3; 95% CI, -0.60 to -0.02). Equations based on both creatinine and CysC were the least biased (SMD, -0.14; 95% CI, -0.46 to 0.18). Chronic kidney disease-Epi-serum creatinine-CysC (CESC) was the least biased but had low precision and underestimated GFR by -3.6 mL/minute/1.73 m² (95% CI, -17.4 to 10.3). All equations significantly overestimated GFR (+21.7 mL/minute/1.73 m² ; 95% CI, 17.7-25.7) at GFR <60 mL/minute/1.73 m² ; of these, chronic kidney disease-Epi-CysC (10.3 mL/minute/1.73 m² ; 95% CI, 2.1-18.4) and GFR Assessment in Liver Disease (12.6 mL/minute/1.73 m² ; 95% CI, 7.2-18.0) were the least biased followed by Royal Free Hospital (15 mL/minute/1.73 m² ; 95% CI, 5.5-24.6) and Modification of Diet in Renal Disease 6 (15.7 mL/minute/1.73 m² ; 95% CI, 10.6-20.8); however, there was an overlap in the precision of estimates, and the studies were limited. In ascites, overestimation of GFR was common (+8.3 mL/minute/1.73 m² ; 95% CI, -3.1 to 19.7). However, overestimation of GFR by 10 to 20 mL/minute/1.73m² is common in patients with cirrhosis with most equations in ascites and/or kidney dysfunction. A tailored approach is required especially for decisions regarding dual-organ transplantation.

Kidney Disease After Nonkidney Solid Organ Transplant

Nonkidney solid organ transplants (NKSOTs) are increasing in the United States with improving long-term allograft and patient survival. CKD is prevalent in patients with NKSOT and is associated with increased morbidity and mortality especially in those who progress to end-stage kidney disease. Calcineurin inhibitor nephrotoxicity is a main contributor to CKD after NKSOT, but other factors in the pretransplant, peritransplant, and post-transplant period can predispose to progressive kidney dysfunction. The management of CKD after NKSOT generally follows society guidelines for native kidney disease. Kidney-protective and calcineurin inhibitor-sparing immunosuppression has been explored in this population and warrants a discussion with transplant teams. Kidney transplantation in NKSOT recipients remains the kidney replacement therapy of choice for suitable candidates, as it provides a survival benefit over remaining on dialysis.

Current knowledge about biomarkers of acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) is common in advanced cirrhosis. Prerenal azotemia, hepatorenal syndrome, and acute tubular necrosis are the main causes of AKI in patients with cirrhosis. Evaluation of renal function and differentiation between functional and structural kidney injury are important issues in the management of cirrhosis. However, AKI in cirrhosis exists as a complex clinical spectrum rather than concrete clinical entity. Based on current evidence, changes in serum creatinine (Cr) levels remain the most appropriate standard for defining AKI in cirrhosis. However, serum Cr has a limited role in assessing renal function in this population. This review examines previous studies that investigated the ability of recent biomarkers for AKI in cirrhosis from the perspective of earlier and accurate diagnosis, classification of AKI phenotype, and prediction of clinical outcomes. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin have been extensively studied in cirrhosis, and have facilitated improved diagnosis and prognosis prediction in patients with AKI. In addition, urine N-acetyl-β-D-glucosaminidase, interleukin 18, and kidney injury molecule 1 are other promising biomarkers for advanced cirrhosis. However, the clinical significance of these markers remains unclear because there are no cut-off values defining the normal range and differentiating phenotypes of AKI. In addition, AKI has been defined in terms of serum Cr, and renal biopsy-the gold standard-has not been carried out in most studies. Further discovery of innovate biomarkers and incorporation of various markers could improve the diagnosis and prognosis prediction of AKI, and will translate into meaningful improvements in patient outcomes.

Assessment of kidney function: clinical indications for measured GFR

In the vast majority of cases, glomerular filtration rate (GFR) is estimated using serum creatinine, which is highly influenced by age, sex, muscle mass, body composition, severe chronic illness and many other factors. This often leads to misclassification of patients or potentially puts patients at risk for inappropriate clinical decisions. Possible solutions are the use of cystatin C as an alternative endogenous marker or performing direct measurement of GFR using an exogenous marker such as iohexol. The purpose of this review is to highlight clinical scenarios and conditions such as extreme body composition, Black race, disagreement between creatinine- and cystatin C-based estimated GFR (eGFR), drug dosing, liver cirrhosis, advanced chronic kidney disease and the transition to kidney replacement therapy, non-kidney solid organ transplant recipients and living kidney donors where creatinine-based GFR estimation may be invalid. In contrast to the majority of literature on measured GFR (mGFR), this review does not include aspects of mGFR for research or public health settings but aims to reach practicing clinicians and raise their understanding of the substantial limitations of creatinine. While including cystatin C as a renal biomarker in GFR estimating equations has been shown to increase the accuracy of the GFR estimate, there are also limitations to eGFR based on cystatin C alone or the combination of creatinine and cystatin C in the clinical scenarios described above that can be overcome by measuring GFR with an exogenous marker. We acknowledge that mGFR is not readily available in many centres but hope that this review will highlight and promote the expansion of kidney function diagnostics using standardized mGFR procedures as an important milestone towards more accurate and personalized medicine.

Renal Protective Effect of Everolimus in Liver Transplantation: A Prospective Randomized Open-Label Trial

Supplemental Digital Content is available in the text.

Renal dysfunction is associated with poor long-term outcomes after liver transplantation. We examined the renal sparing effect of everolimus (EVR) compared to standard calcineurin inhibitor (CNI) immunosuppression with direct measurements of renal function over 24 months.

Position paper on liver and kidney diseases from the Italian Association for the Study of Liver (AISF), in collaboration with the Italian Society of Nephrology (SIN)

Liver and kidney are strictly connected in a reciprocal manner, in both the physiological and pathological condition. The Italian Association for the Study of Liver, in collaboration with the Italian Society of Nephrology, with this position paper aims to provide an up-to-date overview on the principal relationships between these two important organs. A panel of well-recognized international expert hepatologists and nephrologists identified five relevant topics: 1) The diagnosis of kidney damage in patients with chronic liver disease; 2) Acute kidney injury in liver cirrhosis; 3) Association between chronic liver disease and chronic kidney disease; 4) Kidney damage according to different etiology of liver disease; 5) Polycystic kidney and liver disease. The discussion process started with a review of the literature relating to each of the five major topics and clinical questions and related statements were subsequently formulated. The quality of evidence and strength of recommendations were graded according to the GRADE system. The statements presented here highlight the importance of strong collaboration between hepatologists and nephrologists for the management of critically ill patients, such as those with combined liver and kidney impairment.

LEVERSON G, FOLEY D, D. MEZRICH J, KANMAZ T, M. ANDAÇOĞLU O, M. D’ALESSANDRO A, S. ACARLI K, KALAYOĞLU M, A. FERNANDEZ L. A comparison of rates and severity of chronic kidney disease in deceased-donor and living-donor liver transplant recipients: times matter

Background/aim

The progression of chronic kidney disease (CKD) in recipients of living-donor liver transplant (LDLT) compared to deceased-donor liver transplant (DDLT) has not been studied in the literature. We hypothesize that CKD stage progression in LDLT recipients is reduced compared to that of their DDLT counterparts.

Materials and methods

A retrospective study was undertaken including 999 adult, single-organ, primary liver transplant recipients (218 LDLT and 781 DDLT) at 2 centers between January 2003 and December 2012, in which CKD progression and regression were evaluated within the first 3 years after transplantation.

Results

Waiting time from evaluation to transplantation was significantly lower in LDLT patients compared to recipients of DDLT. CKD stage progression from preoperative transplant evaluation to transplantation was significantly greater in DDLT. Deceased-donor liver transplant recipients continued to have higher rates of clinically significant renal disease progression (from stage I–II to stage III–V) across multiple time points over the first 3 years posttransplant. Furthermore, a greater degree of CKD regression was observed in recipients of LDLT.

Conclusion

It can be concluded that LDLT provides excellent graft and patient survival, significantly reducing the overall incidence of clinically significant CKD stage progression when compared to DDLT. Moreover, there is a significantly higher incidence of CKD stage regression in LDLT compared to DDLT. These observations were maintained in both high and low model for end-stage liver disease(MELD)populations. This observation likely reflects earlier access to transplantation in LDLT as one of the contributing factors to preventing CKD progression.

Chronic kidney disease in patients with non-alcoholic fatty liver disease: What the Hepatologist should know?

The association of non-alcoholic fatty liver disease (NAFLD) with several other diseases has gained increased interest during the recent years. Among them, the association with chronic kidney disease (CKD) has emerged as an important one regarding both its prevalence and significance. The early recognition of this association is important for the prognosis of patients with NAFLD and CKD. Apart from early diagnosis, the accurate assessment of renal function is also crucial in the clinical practice of hepatologists. Several methods have been used in the literature for the evaluation of kidney function in patients with NAFLD up to now. In this respect, calculators (or formulas) for the estimation of Glomerular Filtration Rate (eGFR) and Albumin to Creatinine Ratio (ACR) are simple, practical and easily available methods for this purpose. The aim of this review is to report on the epidemiology and pathophysiology of the relationship between NAFLD and CKD and to describe the different methods of kidney function assessment in patients with NAFLD. The collection of all relevant data regarding this association will provide hepatologists with pertinent knowledge on this topic and allow them to use the most accurate methods for the assessment of kidney function in these patients in their clinical practice.

Liver and kidney transplantation in polycystic liver and kidney disease

OBJECTIVE

To evaluate the results of isolated liver and combined liver and kidney transplantation in a retrospective series of 32 patients with hepatorenal liver and kidney disease.

MATERIALS AND METHODS

A retrospective observational study that enrolled patients with polycystic liver disease (PLD) and polycystic liver and kidney disease (PLKD) who were evaluated for transplantation between January 1999 and December 2019 at Hospital Clínic de Barcelona [Clinical Hospital of Barcelona].

RESULTS

We included a total of 53 patients enrolled, 32 (60.3%) had indication for transplantation, of which 12 received a single liver transplant and 20 received a double liver and kidney transplant. The mean age was 52 years and 83.9% of the recipients were women. The main indication for liver transplantation was disabling symptomatic hepatomegaly (93.5%). Among the postoperative complications, in the combined liver and kidney transplant group, hepatic artery thrombosis in one case and renal artery thrombosis in other were detected. In both groups there was one case of inferior vena cava lesion. Three patients presented acute cellular rejection responding to corticosteroids and one presented humoral rejection which was treated with plasmapheresis. During the follow-up period of 80 (27-121) months, the liver transplant survival rate was 100% and the kidney transplant survival rate was 90%. Two patients in the combined liver and kidney transplant group died (one due to cardiovascular causes and the other due to intestinal adenocarcinoma).

CONCLUSIONS

Isolated liver transplantation or combined liver and kidney transplantation in selected patients with polycystic disease yields excellent results, with few complications, very good transplant survival and excellent patient survival (93.8%).

Optimizing the Selection of Patients for Simultaneous Liver-Kidney Transplant

Simultaneous liver-kidney transplantation has increased significantly in the Model for End Stage Liver Disease era. The transplantation policy has evolved significantly since the implementation of allocation based on the Model for End Stage Liver Disease. Current policy takes into account the medical eligibility criteria for simultaneous liver-kidney transplantation listing. It also provides a safety net option and prioritizes kidney transplant after liver transplant recipients who are unlikely to recover their renal function within 60 to 365 days after liver transplant alone. This review seeks to understand the underlying challenges in carefully selecting the candidates while optimizing the patient selection.

Sex-related associations among anemia, body mass index, and kidney function in Koreans: A cross-sectional study with propensity analysis

The association between anemia and body mass index (BMI) in Koreans, considering kidney function, has not been clarified. Thus, we aimed to examine the association between anemia and BMI among Korean adults aged ≥19 years.This retrospective cross-sectional study evaluated male and female Korean adults aged ≥19 years who participated in the 5th, 6th, and 7th Korean National Health and Nutrition Examination Surveys (KNHANES) conducted between 2010 and 2017 were used. The participants were classified as underweight, normal weight, and overweight according to their BMI. Anemia was defined as hemoglobin levels of <13 g/dL for men and <12 g/dL for women according to the World Health Organization standards. Kidney function was evaluated according to the estimated glomerular filtration rate (eGFR), with abnormal kidney function in men defined as eGFR <60 mL/min/1.73 m2. Clinicodemographic variables were analyzed using logistic regression adjusted for weight. After propensity score matching (PSM), 6596 study participants were divided into 2 groups of 3298 participants each. Additionally, subgroup analysis by sex and kidney function was performed.On PSM, similar distribution patterns were obtained between the anemia and non-anemia groups; significant differences in BMI; kidney function; level of hemoglobin, hematocrit, and serum creatinine; iron intake; and eGFR were also observed between these groups. Anemia and BMI showed a significant association in both crude and adjusted logistic regression models. In model 2, which was adjusted for age, sex, education level, household income, alcohol consumption, smoking status, and exercise period, underweight men with abnormal kidney function showed a significantly higher risk of anemia than did normal weight men (odds ratio [OR]: 3.27; 95% confidence interval [CI]: 1.25-8.57; P = .016). Meanwhile, overweight men showed a significantly lower risk of anemia than did normal weight men (OR: 0.48; 95% CI: 0.33-0.70, P < .001).Anemia is associated with BMI according to sex. Compared with normal weight men, underweight men with abnormal kidney function had a significantly higher prevalence of anemia after adjusting for kidney function and sex, thus highlighting their need for careful management for anemia.

LIRER score - a valuable tool to predict medium-long-term outcomes in hepatic cirrhosis decompensation

BACKGROUND

The liver-renal-risk (LIRER) score was developed to predict adverse outcomes in cirrhotic patients with Model for End-stage Liver Disease (MELD)<18, helping the allocation to liver transplantation in this population. We aimed to assess its prognostic performance compared to other prognostic scores in first admission for hepatic cirrhosis decompensation.

METHODS

Retrospective study that included patients admitted for initial decompensation of cirrhosis between January 2010 and February 2017. The LIRER, Child-Pugh (CP), MELD and MELD-sodium (MELD-Na) scores were calculated at admission.

RESULTS

One-hundred and forty-six patients were included, 65.1% with MELD < 18. LIRER was a predictor of in-stay (AUC 0.70; p = .04), first-year (0.70; p < .001), two-years (0.72; p < .001) and overall mortality (0.70; p < .001), being the only score with an acceptable discriminating ability (AUC ≥ 0.70). Stratifying patients in MELD < 18 and ≥18, LIRER was found to be an independent predictor of first-year, two-years and overall-mortality only in MELD < 18 patients (AUC 0.67; 0.70; 0.72), being superior to all other scores predicting first-year mortality and the only with an AUC with a reasonable discriminating ability for predicting two-years and overall-mortality. The LIRER was also a predictor of 30-days hospital readmission (AUC 0.75; p < .001), independently of MELD, with patients with LIRER > 15.9 having a significantly higher probability to be readmitted at 30 days.

CONCLUSIONS

The LIRER score is a predictor of first-year, two-years and overall-mortality in decompensated cirrhosis, particularly in patients with MELD < 18. LIRER is therefore an important tool to predict medium-long-term outcomes in this population. Besides, it allows predicting the 30-days readmission probability in overall patients, independently of MELD.

Incidence of chronic kidney disease after orthotopic liver transplantation in a Chinese cohort

BACKGROUND

Kidney dysfunction frequently occurred after orthotopic liver transplantation (OLT). Chronic renal disease (CKD) is a complicated problem and is associated with increased mortality. The aim of this study is to find the risk factors for the incidence of CKD at 1 year after OLT in China.

METHODS

From January 2017 to December 2017, we retrospectively assessed 280 recipients in our single center. Chronic renal failure was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² for 3 months, regardless of the presence or absence of structural kidney damage. Cox proportional hazard model was used to identify the factors to the incidence of CKD after liver transplantations. Kaplan-Meier plots with log-rank test were presented to evaluate patient survival time in those with and without CKD.

RESULTS

With a median follow-up of 17.4 months, 48 patients developed CKD after liver transplantations, representing 17.1% of the cohort. The cox-regression model showed that recipients age (HR = 1.097, P < 0.01), AKI (HR = 1.542, P < 0.01) and MELD score (HR = 1.077, P < 0.01) were significantly associated with the development of post-transplant CKD at 1 year. Recipient survival at 1 year was significantly worse in recipients with CKD compared to those without CKD (P < 0.01) after adjustment by age and gender.

CONCLUSION

Our findings suggested that age, AKI and MELD score were associated with the incidence of CKD 1 year after OLT in a Chinese cohort. Recipients with CKD were associated with worse survival.

Interaction between tacrolimus, MELD score and acute kidney injury after liver transplantation. Analysis on a large contemporary bicenter meld-era series

BACKGROUND

Acute kidney injury (AKI) after liver transplantation (LT) is a common problem with complex management. The aims were to analyze the profile of AKI-RIFLE categories in the post-transplant setting of a wide multicentre cohort of patients in the MELD era and to specifically determine the effect of tacrolimus-based (TACRO) immunosuppressive regimes on the development of AKI.

METHODS

A retrospective analysis of 550 (2007-2012) consecutive patients transplanted at Reina Sofia, Cordoba, and King's College Hospital, London, was performed. Inclusion criterion was to have CNI as part of initial immunosuppression immediately after LT.

RESULTS

After exclusion criteria, a total of 477 patients were analyzed. Incidence of AKI within the first 2 weeks after LT was 65.8% (AKI-Risk), 41.3% (AKI-Injury), and 12.3% (AKI-Failure). The development of any type of AKI had no impact on short- and/or long-term survival up to 3 years after the transplant. Moreover, AKI was almost universal in the early post-transplant period and TACRO trough concentrations during the first 2 weeks after the transplant were not predictors of AKI in none of its categories in the multivariate analyses.

CONCLUSIONS

Low-TACRO-based regimes were not as useful as expected in the prevention of AKI when analyzed in the context of a large contemporary LT series.

Lack of Relationship Between Renal Function and Genetic Variants of CYP3A4, CYP3A5, MDR1, MRP2, UGT1A9, UGT1A8, and UGT2B7 in Patients After Liver Transplantation in a 2-Year Follow-up

BACKGROUND

The prolonged survival time after liver transplantation (LTX) creates the possibility of the occurrence and development of complications in the late post-transplantation period. Deterioration of renal function is 1 of these complications. The nephrotoxicity of calcineurin inhibitors (CNIs) and their metabolites produced during pharmacokinetic processes in the body is also postulated. The study was aimed at assessment of the relationship between selected single gene polymorphisms (SNPs) for enzymes and transport proteins and change of estimated glomerular filtration rate (ΔeGFR) during 2-year follow-up in LTX patients.

METHODS

The study involved 244 patients after LTX (105 women [43.0%] and 139 men [57.0%]) receiving tacrolimus (191; 78.3%) or cyclosporine A (53; 21.7%). The study protocol conforms with the Declaration of Helsinki.

RESULTS

We have not observed significant differences of ΔeGFR between groups distinguished based on analyzed genotypes in patients treated with cyclosporine or tacrolimus.

CONCLUSION

Genetic variations of CYP3A4, CYP3A5, MDR1, MRP2, UGT1A9, UGT2B7, and UGT2B7 tested in LTX recipients are not associated with kidney function during the 24-month follow-up.

Acute kidney injury in cirrhosis: implications for liver transplantation

PURPOSE OF REVIEW

Acute kidney injury (AKI) in cirrhosis consists of varying phenotypes, with hepatorenal syndrome (HRS) representing a single entity. Prompt recognition and diagnosis of AKI cause identifies appropriate therapeutic measures. This review provides an overview of AKI definitions, highlights challenges in quantifying renal impairment in cirrhosis, lists novel diagnostic AKI biomarkers, and summarizes transplantation implications.

RECENT FINDINGS

Biomarkers (neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, interleukin-18, and liver-type fatty acid-binding protein) may assist in the identification of underlying acute tubular necrosis. Of these, neutrophil gelatinase-associated lipocalin is the most promising; however, significant overlap occurs among AKI phenotypes, with diagnostic values yet to be defined. Mainstay treatment of HRS consists of albumin and vasopressors. Acute-on-chronic liver failure grade independently predicts response to terlipressin treatment. Many end-stage liver disease patients with AKI have underlying chronic kidney disease with important implications on pre and postliver transplantation mortality. Simultaneous liver-kidney transplant candidacy is based on low likelihood of renal recovery.

SUMMARY

Novel biomarkers may assist in identification of acute tubular necrosis and persistent/severe AKI. Norepinephrine has been suggested to be inferior to terlipressin, with additional research required. Increasing acute-on-chronic liver failure grade correlates with lower likelihood of vasopressor response in HRS. Severe preliver transplantation AKI confers significantly worse postliver transplantation renal outcomes.

The SURF (Italian observational study for renal insufficiency evaluation in liver transplant recipients): a post-hoc between-sex analysis

Background

Female sex has been reported as an independent predictor of severe post-liver transplantation (LT) chronic kidney disease. We performed a by sex post-hoc analysis of the SURF study, that investigated the prevalence of renal impairment following LT, aimed at exploring possible differences between sexes in the prevalence and course of post-LT renal damage.

Methods

All patients enrolled in the SURF study were considered evaluable for this sex-based analysis, whose primary objective was to evaluate by sex the proportion of patients with estimated Glomerular Filtration Rate (eGFR) < 60 ml/min/1.73m² at inclusion and follow-up visit.

Results

Seven hundred thirty-eight patients were included in our analysis, 76% males. The proportion of patients with eGFR < 60 mL/min/1.73 m² was significantly higher in females at initial study visit (33.3 vs 22.8%; p = 0.005), but also before, at time of transplantation (22.9 vs 14.7%; p = 0.0159), as analyzed retrospectively. At follow-up, such proportion increased more in males than in females (33.9 vs 26.0%, p = 0.04). Mean eGFR values decreased over the study in both sexes, with no significant differences. Statistically significant M/F differences in patient distribution by O’Riordan eGFR levels were observed at time of transplant and study initial visit (p = 0.0005 and 0.0299 respectively), but not at follow-up.

Conclusions

Though the limitation of being performed post-hoc, this analysis suggests potential sex differences in the prevalence of renal impairment before and after LT, encouraging further clinical research to explore such differences more in depth.

External Validation of a Pretransplant Biomarker Model (REVERSE) Predictive of Renal Recovery After Liver Transplantation

In patients with end-stage liver disease, the ability to predict recovery of renal function following liver transplantation (LT) remains elusive. However, several important clinical decisions depend on whether renal dysfunction is recoverable after LT. We used a cohort of patients undergoing LT to independently validate a published pre-LT model predictive of post-transplant renal recovery (Renal Recovery Assessment at Liver Transplant [REVERSE]: high osteopontin [OPN] and tissue inhibitor of metalloproteinases-1 [TIMP-1] levels, age < 57, no diabetes). Serum samples pre-LT and 4-12 weeks post-LT (n = 117) were analyzed for kidney injury proteins from three groups of recipients: (1) estimated glomerular filtration rate (eGFR) < 30 mL/minute/1.73 m² prior to and after LT (irreversible acute kidney injury [AKI]), (2) eGFR < 30 mL/minute/1.73 m² prior to LT and >50 mL/minute/1.73 m² after LT (reversible AKI [rAKI]) (3) eGFR > 50 mL/minute/1.73 m² prior to and after LT (no AKI). In patients with elevated pre-LT serum levels of OPN and TIMP-1, recovery of renal function correlated with decreases in the level of both proteins. At 4 weeks post-LT (n = 77 subset), the largest decline in OPN and TIMP-1 was seen in the rAKI group. Validation of the REVERSE model in this independent data set had high area under the curve (0.78) in predicting full post-LT renal recovery (sensitivity 0.86, specificity 0.6, positive predictive value 0.81, negative predictive value 0.69). Our eGFR findings were confirmed using measured GFR. Conclusion: The REVERSE model, derived from an initial training set combining plasma biomarkers and clinical characteristics, demonstrated excellent external validation performance characteristics in an independent patient cohort using serum samples. Among patients with kidney injury pre-LT, the predictive ability of this model may prove beneficial in clinical decision-making both prior to and following transplantation.

Chronic Kidney Disease After Liver Transplantation: Impact of Extended Criteria Grafts

The use of extended criteria donor (ECD) grafts has been associated with acute kidney injury (AKI) after liver transplantation. However, the relation between graft quality and development of chronic kidney disease (CKD) remains unknown. Therefore, the aim of this study was to analyze the impact of ECD grafts for CKD after liver transplantation. All patients (2007-2015) transplanted for end-stage liver disease at our center were assessed. Longterm kidney function was divided into 4 groups: no CKD (estimated glomerular filtration rate [eGFR], ≥60 mL/minute/1.73 m² ), mild CKD (eGFR, 30-59 mL/minute/1.73 m² ), severe CKD (eGFR, 15-29 mL/minute/1.73 m² ), and end-stage renal disease (ESRD). Marginal donation after brain death (DBD) grafts (donor age, >70 years; body mass index, >35 kg/m² ; cold storage, >12 hours) and donation after circulatory death (DCD) grafts were considered ECD grafts. Overall, 926 patients were included, and 43% received an ECD graft (15% marginal DBD; 28% DCD). After 5 years, 35% developed CKD; severe CKD and ESRD occurred in only 2% and 1%, respectively. CKD rates were comparable for all 3 graft groups (standard group, 36%; marginal DBD group, 29%; DCD group, 35%; standard versus marginal DBD groups, P = 0.16; standard versus DCD group, P = 0.80). None of the ECD criteria were identified as independent risk factors in a Cox regression model for CKD. Risk factors included recipient age, female sex, and preoperative kidney function. Furthermore, recipients who had severe acute kidney injury (AKI; Kidney Disease: Improving Global Outcomes stages 2 and 3) had a 1.8-fold increased risk for CKD. Longterm kidney function of recipients with severe AKI depended on the recovery of kidney function in the first postoperative week. In conclusion, there is no direct relation between the use of ECD grafts and CKD after liver transplantation. However, caution should be taken in recipients who experience severe AKI, regardless of graft type.

Pretransplant renal function evaluated by serum cystatin C was associated with mortality after liver transplantation: a single-center experience

Background

In the model for end-stage liver disease (MELD) score, renal function was well thought to be associated with the prognosis of liver recipients. Serum cystatin C (CystC)-based equations were considered more accurate for calculating estimated glomerular filtration rate (eGFR) than creatinine (Pcr) based equations. Thus, we aimed to assess the association between eGFR estimated by chronic kidney disease epidemiology collaboration (CKD-EPI)-CystC equation and post-transplantation mortality.

Methods

From January 2015 to January 2018, prior to liver transplantation (LT) and other clinical parameters, CystC was collected in all 307 consecutive patients who underwent LT at our center. Patients were divided into four groups according to the Kidney Disease Outcomes Quality Initiative (KDOQI) classification.

Results

Based on CKD-EPI-CystC and the KDOQI classification, 117 patients (38.1%) were stage I, 76 (24.8%) were stage II, 85 (27.7%) were stage III, and 29 (9.4%) were stage IV-V. After univariate and multivariate analysis, MELD score [hazard ratio (HR) =1.035; 95% confidence interval (CI), 1.006-1.066; P=0.018], associated HCC (HR =2.314; 95% CI, 1.253-4.273; P=0.007), and KDOQI stage III (HR =1.850; 95% CI, 1.001-3.419; P=0.049), and stage IV-V (HR =3.915; 95% CI, 1.843-8.316; P<0.001) according to CKD-EPI-CystC equation were confirmed to be independent prognostic factors for post-LT survival.

Conclusions

The pretransplant renal function evaluated by serum CystC was associated with mortality after LT and could be used for predicting post-transplant survival.

Combined liver-kidney transplantation versus liver transplant alone based on KDIGO stratification of estimated glomerular filtration rate: data from the United Kingdom Transplant registry - a retrospective cohort study

Patient selection for combined liver-kidney transplantation (CLKT) is a current issue on the background of organ shortage. This study aimed to compare outcomes and post-transplant renal function for patients receiving CLKT and liver transplantation alone (LTA) based on native renal function using estimated glomerular filtration rate (eGFR) stratification. Using the UK National transplant database (NHSBT) 6035 patients receiving a LTA (N = 5912; 98%) or CLKT (N = 123; 2%) [2001-2013] were analysed, and stratified by KDIGO stages of eGFR at transplant (eGFR group-strata). There was no difference in patient/graft survival between LTA and CLKT in eGFR group-strata (P > 0.05). Of 377 patients undergoing renal replacement therapy (RRT) at time of transplantation, 305 (81%) and 72 (19%) patients received LTA and CLKT respectively. A significantly greater proportion of CLKT patients had severe end-stage renal disease (eGFR < 30 ml/min/1.73 m² ) at 1 year post-transplant compared to LTA (9.5% vs. 5.7%, P = 0.001). Patient and graft survival benefit for patients on RRT at transplantation was favouring CLKT versus LTA (P = 0.038 and P = 0.018, respectively) but the renal function of the long-term survivors was not superior following CLKT. The data does not support CLKT approach based on eGFR alone, and the advantage of CLKT appear to benefit only those who are on established RRT at the time of transplant.

How to estimate renal function in patients with liver disease: choosing the most suitable equation

BACKGROUND

Hepatitis B virus (HBV) infection is a public health challenge, especially in China. In clinical practice, HBV infection is associated with nephropathy. Impaired renal function is frequently observed in compensated Chronic Hepatitis B (CHB) and cirrhosis (LC). Thus, renal function must be monitored to avoid nephrotoxic effects before and during nucleoside analog treatment. Investigating the predictive markers of early renal dysfunction is essential. New GFR-predicting equations, based on Pcr and/or CystC, have been recently recommended in the general population, but their performance in liver disease patients has been rarely studied. In this study, we will discuss how to detect renal dysfunction in patients with HBV infection.

METHODS

A total of 16 LC patients and 23 CHB patients were enrolled in this study, and we collected and compared the clinical data of the two groups. The estimated glomerular filtration rates (eGFRs) were also calculated by several equations. All patients received 99mTc-DTPA dynamic radionuclide imaging examinations to obtain mGFRs as the reference standard. To evaluate the performance of any equation in the CHB and LC groups, paired t test, Pearson's correlation, Kappa analysis and Bland-Altman plots were utilized. Moreover, all 39 subjects were divided into two groups (according to GFR > 90 mL/min/1.73 m²). We compared the serum and urinary markers of kidney injury between the two groups and selected the indicators of renal injury by univariate analysis.

RESULTS

The mGFR was 72.26 ± 20.69 mL/min/1.73 m² in the LC group, and 87.49 ± 25.91 mL/min/1.73 m² in the CHB group. The paired t test results of eGFR and mGFR showed no difference between eGFR (estimated by the CHINAcr-cys equation) and mGFR (p > 0.05) in the compensated LC and CHB groups. The difference between mGFR and eGFR estimated by other methods was obvious (p < 0.05). Comparing the eGFRs (estimated by 5 different equations) with mGFR in the compensated LC and CHB groups, Pearson's correlation showed that only eGFR (estimated by the CHINAcr-cys equation) had a significant correlation coefficient in CHB (r = 0.678, p = 0.000) and had the highest R² (R² = 0.459) among all other measures. The kappa consistency test showed that eGFR from CHINAscr-cys had poor consistency with mGFR in the compensated LC group but moderate consistency in the CHB group. Bland-Altman consistency analysis showed that in the CHB group, the CHINAcr-cys and CKD-EPIcr equations presented narrower acceptable limits than did the aMDRD, c-aMDRD, and CKD-EPIcr-cys equations (62.8, 56.1 vs .85.7, 102.9, 93.6 mL/min per 1.73 m²). In the compensated LC group, the CHINAcr-cys and CKD-EPIcr equations presented narrower acceptable limits than did the aMDRD, c-aMDRD, and CKD-EPIcr-cys equations (83.6, 81.3 vs. 98, 113.5, 106.3 mL/min per 1.73 m²). Serum or urinary markers were compared with renal function (GFR > 90 mL/min/1.73 m²) and showed International normalized ratio (INR) (p = 0.009), creatinine (p = 0.006), urine N-acetyl-β-glucosaminidase (NAG) (p = 0.001) and serum cystatin C (CysC) (p = 0.044).

CONCLUSION

The CHINAcr-cys equation may be more suitable for the estimation of GFR in Chinese patients with CHB or compensated cirrhosis. INR, creatinine, NAG, and CysC are proper biomarkers for screening renal dysfunction in Chinese patients with CHB or compensated LC.

A Model for Glomerular Filtration Rate Assessment in Liver Disease (GRAIL) in the Presence of Renal Dysfunction

Estimation of glomerular filtration rate (eGFR) in patients with liver disease is suboptimal in the presence of renal dysfunction. We developed a model for GFR assessment in liver disease (GRAIL) before and after liver transplantation (LT). GRAIL was derived using objective variables (creatinine, blood urea nitrogen, age, gender, race, and albumin) to estimate GFR based on timing of measurement relative to LT and degree of renal dysfunction (www.bswh.md/grail). The measured GFR (mGFR) by iothalamate clearance (n = 12,122, 1985-2015) at protocol time points before/after LT was used as reference. GRAIL was compared with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD-4, MDRD-6) equations for mGFR < 30 mL/min/1.73 m² . Prediction of development of chronic kidney disease (mGFR < 20 mL/min/1.73 m² , initiation of chronic dialysis) and listing or receipt of kidney transplantation within 5 years was examined in internal cohort (n = 785) and external validation (n = 68,217, 2001-2015). GRAIL had less bias and was more accurate and precise as compared with CKD-EPI, MDRD-4, and MDRD-6 at time points before/after LT for low GFR. For mGFR < 30 mL/min/1.73 m² , the median difference (eGFR-mGFR) was GRAIL: 5.24 (9.65) mL/min/1.73 m² as compared with CKD-EPI: 8.70 (18.24) mL/min/1.73 m² , MDRD-4: 8.82 (17.38) mL/min/1.73 m² , and MDRD-6: 6.53 (14.42) mL/min/1.73 m² . Before LT, GRAIL correctly classified 75% as having mGFR < 30 mL/min/1.73 m² versus 36.1% (CKD-EPI), 36.1% (MDRD-4), and 52.8% (MDRD-6) (P < 0.01). An eGFR < 30 mL/min/1.73 m² by GRAIL predicted development of CKD (26.9% versus 4.6% CKD-EPI, 5.9% MDRD-4, and 10.5% MDRD-6) in center data and needing kidney after LT (48.3% versus 22.0% CKD-EPI versus 23.1% MDRD-4 versus 48.3% MDRD-6, P < 0.01) in national data within 5 years after LT. Conclusion: GRAIL may serve as an alternative model to estimate GFR among patients with liver disease before and after LT at low GFR.

Cardiovascular Disease Outcomes Related to Early Stage Renal Impairment After Liver Transplantation

BACKGROUND

In the general population, even mild renal disease is associated with increased cardiovascular (CV) complications. Whether this is true in liver transplant recipients (LTR) is unknown.

METHODS

This was a retrospective cohort study of 671 LTR (2002-2012) from a large urban tertiary care center and 37 322 LTR using Vizient hospitalization data linked to the United Network for Organ Sharing. The 4-variable Modification of Diet in Renal Disease equation estimated glomerular filtration rate (eGFR). Outcomes were 1-year CV complications (death/hospitalization from myocardial infarction, heart failure, atrial fibrillation, cardiac arrest, pulmonary embolism, or stroke) and mortality. Latent mixture modeling identified trajectories in eGFR in the first liver transplantation (LT) year in the 671 patients.

RESULTS

Mean (SD) eGFR was 72.1 (45.7) mL/min per 1.73 m. Six distinct eGFR trajectories were identified in the local cohort (n = 671): qualitatively normal-slow decrease (4% of cohort), normal-rapid decrease (4%), mild-stable (18%), mild-slow decrease (35%), moderate-stable (30%), and severe-stable (9%). In multivariable analyses adjusted for confounders and baseline eGFR, the greatest odds of 1-year CV complications were in the normal-rapid decrease group (odds ratio, 10.6; 95% confidence interval, 3.0-36.9). Among the national cohort, each 5-unit lower eGFR at LT was associated with a 2% and 5% higher hazard of all-cause and CV-mortality, respectively (P < 0.0001), independent of multiple confounders.

CONCLUSIONS

Even mild renal disease at the time of LT is a risk factor for posttransplant all-cause and CV mortality. More rapid declines in eGFR soon after LT correlate with risk of adverse CV outcomes, highlighting the need to study whether early renal preservation interventions also reduce CV complications.

Population pharmacokinetics of fluconazole in liver transplantation: implications for target attainment for infections with Candida albicans and non-albicans spp

OBJECTIVES

The study aims to assess the population pharmacokinetics of fluconazole and the adequacy of current dosages and breakpoints against Candida albicans and non-albicans spp. in liver transplant (LT) patients.

PATIENTS AND METHODS

Patients initiated i.v. fluconazole within 1 month from liver transplantation (LTx) for prevention or treatment of Candida spp. infections. Multiple assessments of trough and peak plasma concentrations of fluconazole were undertaken in each patient by means of therapeutic drug monitoring. Monte Carlo simulations were performed to define the probability of target attainment (PTA) with a loading dose (LD) of 400, 600, and 800 mg at day 1, 7, 14, and 28 from LTx, followed by a maintenance dose (MD) of 100, 200, and 300 mg daily of the pharmacokinetic/pharmacodynamic target of AUC_24h/MIC ratio ≥ 55.2.

RESULTS

Nineteen patients were recruited. A two-compartment model with first-order intravenous input and first-order elimination was developed. Patient's age and time elapsed from LTx were the covariates included in the final model. At an MIC of 2 mg/L, a LD of 600 mg was required for optimal PTAs between days 1 and 20 from LTx, while 400 mg was sufficient from days 21 on. A MD of 200 mg was required for patients aged 40-49 years old, while a dose of 100 mg was sufficient for patients aged ≥ 50 years.

CONCLUSIONS

Fluconazole dosages of 100-200 mg daily may ensure optimal PTA against C. albicans, C. parapsilosis, and C. tropicalis. Higher dosages are required against C. glabrata. Estimated creatinine clearance is not a reliable predictor of fluconazole clearance in LT patients.

Chronic Kidney Disease after Liver Transplantation: Recent Evidence

Chronic kidney disease is a common complication after liver transplantation with an incidence ranging between 20% and 80%. Studies of renal function after liver transplantation have yielded conflicting results: the wide range in incidence rates of chronic kidney disease (CKD) following liver transplantation is related to the methods for measuring kidney function, and various criteria for defining renal dysfunction, among others. An important cause of CKD among liver transplant recipients is calcineurin inhibitor-based immunosuppression. Additional predictors of CKD post-liver transplantation include pre-transplant kidney function, peri-operative acute kidney failure, age, and hepatitis C. A recent meta-analysis of observational studies revealed that, in the subgroup of studies provided with glomerular filtration rate at baseline, the summary estimate of relative risk and 95% confidence intervals (CI) for developing chronic renal failure among liver transplant recipients with diminished renal function at transplant was 2.12 (95% CI, 1.01–4.46, p=0.047). Acute renal insufficiency is common immediately after liver transplantation, whereas the course of CKD after liver transplantation appears progressive over time. Only preliminary information exists on kidney pathological findings in recipients of liver transplants with CKD. Introduction of the Model for End-stage Liver Disease for the allocation of liver grafts has not increased the occurrence of renal dysfunction following liver transplantation. Chronic kidney disease following liver transplantation increases cardiovascular burden dramatically. The use of mycophenolic acid- or sirolimus-based immunosuppression in calcineurin-inhibitors sparing protocols is an area of intense research.