Impact of Donation After Circulatory Death on Outcomes of Expanded Criteria Donor Kidney Transplants

Expanded criteria donor (ECD) kidneys experience suboptimal outcomes compared with standard criteria donor kidneys. To examine the additional impact of deceased organ category, donation after circulatory death (DCD), and neurologic determination of death (NDD) on ECD outcomes, we examined 1- and 3-year patient and graft survival in all ECD kidney recipients in our institution between January 2008 and December 2017. Of 166 ECD recipients, 49 (29.5%) were DCD and 117 (70.5%) were NDD. Delayed graft function was higher in the DCD/ECD group 61.2 % vs 32.0 % among NDD/ECD recipients. Graft loss was significantly increased among DCD/ECD (hazard ratio for graft loss 4.81 [95% CI1.78-13.01], P = .002 at 1 year and 2.03 [95% CI 1.03-4.0], P = .042 at 3 years). Death-censored graft loss was higher among DCD/ECD (hazard ratio was 10.12 [95% CI, 2.14, 47.92], P = .004 at 1 year and 2.83 [95% CI, 1.24, 6.46], P = .014 at 3 years). There was no statistically significant difference in all-cause mortality. Our study demonstrated that DCD/ECD kidneys have lower graft survival compared with NDD/ECD kidneys. Time on dialysis, waiting time, and panel reactive antibody should be taken into account when offering these organs to patients.

Microscopic Kidney Disease in Tuberous Sclerosis Complex and Treatment With mTOR Inhibition

Declining kidney function in tuberous sclerosis complex (TSC) is often attributed to large lesions, including angiomyolipomas (AMLs) and cysts, that encroach on the normal parenchyma or that require intervention and loss of parenchyma from surgical debulking or embolization. Consequently, research on inhibitors of the mammalian target of rapamycin (mTOR), a protein complex implicated in TSC pathophysiology for its role in promoting cell growth and proliferation, has largely focused on their ability to reduce AML size. Clinical guidelines distilled from this research limit mTOR inhibition as a first-line treatment to patients with large AMLs. However, chronic kidney disease (CKD) occurs in patients without large AMLs or a history of renal intervention. Alternate mechanisms postulated for CKD in TSC may suggest a role for mTOR inhibition in this population. In this report, we present 2 cases of a microscopic variant of TSC kidney disease causing declining kidney function, as well as anecdotal evidence for the use of mTOR inhibition to improve kidney function in the absence of large AMLs. We highlight the importance of annual kidney function assessment in patients with TSC and suggest a low threshold for kidney biopsy in patients with declining glomerular filtration rate without a clear etiology clinically or radiographically.

Risk and Timing of Major Bleeding Complications Requiring Intervention of the Percutaneous Kidney Biopsy With a Short Observation Protocol: A Retrospective Chart Review

Background

We previously published a retrospective study of kidney biopsies performed in a tertiary care hospital in London, Ontario from 2012 to 2017. This study resulted in a change of practice in our institution to shorter postbiopsy monitoring for outpatients as well as the development of a risk calculator to predict serious bleeding complications.

Objective

The primary objective of this study was to determine whether this shorter monitoring time is adequate in the outpatient setting. A secondary objective was to validate the bleeding risk calculator in both inpatients and outpatients.

Design

This was a retrospective chart review.

Setting

This study was performed at a tertiary academic hospital in London, Ontario, Canada.

Participants

This was a retrospective study of 400 adult patients who underwent kidney biopsy between April 30, 2018 and February 25, 2022 at a tertiary academic hospital in London, Canada.

Methods

We retrospectively assessed frequency and timing of major bleeding complications in patients who underwent kidney biopsy. In secondary analyses, we examined the prediction performance of the risk calculator in discrimination and calibration.

Results

Major bleeding occurred in 7 patients (1.8%). Five of these patients required blood transfusions (1.3%) and 2 required embolization (0.5%). In the outpatient setting, any major bleeding events were identified immediately (1 patient) or on the routine 2-hour ultrasounds (1 patient). The risk calculator showed good discrimination (C-statistic, 0.91, 95% confidence interval [CI] = [0.84 to 0.95]) and calibration (slope, 1.10, 95% CI = [0.47 to 1.74]; intercept, 95% CI = -0.02 [-0.79 to 0.75]), but with much uncertainty in the estimates.

Limitations

The occurrence of only a few major bleeding events limits the reliability of our assessment of our risk calculator.

Conclusions

There appears to be little yield in extending observation beyond 2 hours after an outpatient kidney biopsy with the use of immediate and 2-hour postbiopsy ultrasounds. The bleeding risk calculator (http://perioperativerisk.com/kbrc) warrants further validation.

The effect of late-onset CMV infection on the outcome of renal allograft considering initial graft function

BACKGROUND

Delayed graft function (DGF) increases the renal allograft failure risk. Late-onset Cytomegalovirus (CMV) infection's effect on the association between DGF and allograft failure has not been determined.

METHODS

In this retrospective cohort, we included all renal allograft recipients at London Health Sciences Centre from January 1, 2014 to December 30, 2017, and continued clinical follow-up until February 28, 2020. We determined whether late-onset CMV infection affects the association between DGF and allograft failure in stratified and Cox proportional hazard analyses.

RESULTS

Of 384 patients (median age [interquartile range]: 55 [43.3-63]; 38.7% female), 57 recipients (14.8%) were diagnosed with DGF. Patients with DGF were at a greater risk of CMV infection than patients without DGF (22.8% vs. 11.3%, p = .017). Late-onset CMV infection (odds ratio [OR]: 4.7, 95% CI: 2.07-10.68) and rejection (OR: 9.59, 95% CI: 4.15-22.16) significantly increased the risk of allograft failure in recipients with DGF. Patients with DGF had a significantly greater risk of graft failure than those without DGF (17.5% vs. 6.1%, p = .007). In the adjusted Cox hazard model, CMV infection significantly increased the risk of allograft failure (aHR: 3.19, 95% CI: 1.49-6.84).

CONCLUSION

Late-onset CMV infection considerably increased the risk of graft failure in patients with DGF. A hybrid preventive model including prophylaxis followed by CMV-specific cell-mediated immunity monitoring may decrease the risk of allograft failure in recipients with DGF.

Epidemiology and Outcomes of AKI Treated With Continuous Kidney Replacement Therapy: The Multicenter CRRTnet Study

Rationale & Objective

Continuous kidney replacement therapy (CKRT) is the predominant form of acute kidney replacement therapy used for critically ill adult patients with acute kidney injury (AKI). Given the variability in CKRT practice, a contemporary understanding of its epidemiology is necessary to improve care delivery.

Study Design

Multicenter, prospective living registry.

Setting & Population

1,106 critically ill adults with AKI requiring CKRT from December 2013 to January 2021 across 5 academic centers and 6 intensive care units. Patients with pre-existing kidney failure and those with coronavirus 2 infection were excluded.

Exposure

CKRT for more than 24 hours.

Outcomes

Hospital mortality, kidney recovery, and health care resource utilization.

Analytical Approach

Data were collected according to preselected timepoints at intensive care unit admission and CKRT initiation and analyzed descriptively.

Results

Patients' characteristics, contributors to AKI, and CKRT indications differed among centers. Mean (standard deviation) age was 59.3 (13.9) years, 39.7% of patients were women, and median [IQR] APACHE-II (acute physiologic assessment and chronic health evaluation) score was 30 [25-34]. Overall, 41.1% of patients survived to hospital discharge. Patients that died were older (mean age 61 vs. 56.8, P < 0.001), had greater comorbidity (median Charlson score 3 [1-4] vs. 2 [1-3], P < 0.001), and higher acuity of illness (median APACHE-II score 30 [25-35] vs. 29 [24-33], P = 0.003). The most common condition predisposing to AKI was sepsis (42.6%), and the most common CKRT indications were oliguria/anuria (56.2%) and fluid overload (53.9%). Standardized mortality ratios were similar among centers.

Limitations

The generalizability of these results to CKRT practices in nonacademic centers or low-and middle-income countries is limited.

Conclusions

In this registry, sepsis was the major contributor to AKI and fluid management was collectively the most common CKRT indication. Significant heterogeneity in patient- and CKRT-specific characteristics was found in current practice. These data highlight the need for establishing benchmarks of CKRT delivery, performance, and patient outcomes. Data from this registry could assist with the design of such studies.

Investigation of N,N,N-Trimethyl-L-alanyl-L-proline Betaine (TMAP) as a Biomarker of Kidney Function

Glomerular filtration rate (GFR) is the most widely used tool for the measurement of kidney function, but endogenous biomarkers such as cystatin C and creatinine have limitations. A previous metabolomic study revealed N,N,N-trimethyl-L-alanyl-L-proline betaine (TMAP) to be reflective of kidney function. In this study, we developed a quantitative LCMS assay for the measurement of TMAP and evaluated TMAP as a biomarker of GFR. An assay to measure TMAP was developed using liquid chromatography-mass spectrometry. After validation of the method, we applied it to plasma samples from three distinct kidney disease patient cohorts: nondialysis chronic kidney disease (CKD) patients, patients receiving peritoneal and hemodialysis, and living kidney donors. We investigated whether TMAP was conserved in other mammalian and nonmammalian species, by analyzing plasma samples from Wistar rats with diet-induced CKD and searching for putative matches to the m/z for TMAP and its known fragments in the raw sample data repository "Metabolomics Workbench". The assay can measure plasma TMAP at a lower limit of quantitation (100 ng/mL) with an interday precision and accuracy of 12.8 and 12.1%, respectively. In all three patient cohorts, TMAP concentrations are significantly higher in patients with CKD than in controls with a normal GFR. Further, TMAP concentrations are also elevated in rats with CKD and TMAP is present in the sap produced from Acer saccharum trees. TMAP concentration is inversely related to GFR suggesting that it is a marker of kidney function. TMAP is present in nonmammalian species suggesting that it is part of a biologically conserved process.

The Renal Community Photo Initiative: A Program Report in Ontario, Canada

Purpose of Program:

We initiated the Renal Community Photo Initiative to better understand why some hemodialysis users express significant capacities for resilience and hope, demonstrating outward-looking perspectives and enjoying a rich quality of life.

Sources of Information:

“Photovoice” is a participatory research methodology that encourages individuals to develop positive self-perceptions with photography. Photovoice empowers participants as informants within their communities. Visual arts researchers surveyed existing Photovoice studies to identify gaps in knowledge to be addressed in this study, including challenges related to fostering participant agency and social action. Images and logs were collected and reviewed during organized, participant-led substudy groups. These meetings provided researchers with core study values and direction as to how the images and additional information should be used to raise awareness about living with chronic kidney disease.

Methods:

To address the complexity of the human condition, the Renal Community Photo Initiative offered participants an array of diverse and accessible image-making techniques. No narrative directives for image-making were provided. This qualitative, interdisciplinary, participant-centric study invited adult chronic hemodialysis patients in 4 dialysis units in London and Stratford, Ontario, to participate. The research team designed a selection of different, accessible photo technologies for participant use. Eligible participants were invited to select photographic technologies and given the additional option to write accompanying logs. Researchers organized substudy meetings for participant-led focus groups to discuss core study values and personal encounters with images and image-making. Participants directed how their generated images should be shared with the public and researchers.

Key Findings:

A total of 40 participants have been recruited to date, producing more than 1600 images and an archive of handwritten logs. Three participant-led focus groups have established priorities for image sharing and a core set of values for subsequent study phases. A series of public presentations of participant images took place. The research team will pursue further public presentation opportunities and the development of a suitable research database.

Limitations:

Organizing and categorizing images for access in an interdisciplinary research database remains a challenge. Current health and safety protocols related to COVID-19 require the study to pause recruitment and substudy meetings and reassess immediate outputs for visuals.

Implications:

A qualitative study of this scope offers a new model for participant agency and collaboration. It requires the onboarding of interdisciplinary researchers to effectively engage with its significant image and log archive. Participants should remain involved in directing future steps for disseminating their images. Following substudy directives, researchers are developing visuals for health care and public settings, and determining opportunities for participants to share their experience in both clinic- and public-based settings.

Functional Sodium MRI Helps to Measure Corticomedullary Sodium Content in Normal and Diseased Human Kidneys

Background To the knowledge of the authors, urinary osmolarity is the only tool currently available to assess kidney corticomedullary gradient (CMG). Comparisons between CMG and urinary osmolarity and the use of modalities such as sodium MRI to evaluate renal disease in humans are lacking. Purpose To investigate the ability of sodium MRI to measure CMG dynamics compared with urinary osmolarity after water load in healthy volunteers and CMG in participants with kidney disease. Materials and Methods A prospective study was conducted from July 2020 to January 2021 in fasting healthy volunteers undergoing water load and participants with chronic kidney disease (CKD) from cardiorenal syndrome included in a clinical trial. In both groups, CMG was estimated by measuring the medulla-to-cortex signal ratio from sodium MRI at 3.0 T. A custom-built two-loop (diameter, 18 cm) butterfly radiofrequency surface coil, tuned for sodium frequency (33.786 MHz), was used to acquire renal sodium images. Two independent observers measured all sodium MRI cortical and medullary values for each region of interest to compute the intraclass correlation coefficient. Pearson correlation was performed between urinary osmolarity and CMG. Results Five participants with CKD (mean age, 77 years ± 12 [standard deviation]; all men) and 10 healthy volunteers (mean age, 42 years ± 15; six men, four women) were evaluated. A reduction was observed between baseline and peak urinary dilution time for both mean medulla-to-cortex ratios (1.55 ± 0.11 to 1.31 ± 0.09, respectively; P < .001) and mean urinary osmolarity (756 mOsm/L ± 157 to 73 mOsm/L ± 14, respectively; P < .001) in healthy volunteers. Medulla-to-cortex and corresponding urinary osmolarity were correlated in both groups (r² = 0.22; P < .001). Kidney sodium tissue content was successfully acquired in all five participants with CKD. The intraclass correlation coefficient measurement was 0.99 (P < .001). Conclusion Functional sodium MRI accurately depicted corticomedullary gradient (CMG) dynamic changes in healthy volunteers and demonstrated feasibility of CMG measurement in participants with reduced kidney function. Clinical trial registration no. NCT04170855. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Laustsen and Bøgh in this issue.

Adults with tuberous sclerosis complex: A distinct patient population

OBJECTIVES

There are few data on adults living with tuberous sclerosis complex (TSC), with most studies focusing on pediatric populations. The objective of our study was to examine a large national cohort of adults with TSC, and to describe the clinical characteristics of these adults and the nature of the multidisciplinary care that they receive.

METHODS

Six Canadian medical centers collaborated in this study. Data were collected using a standardized form, and descriptive statistics were used for the analyses.

RESULTS

Our study included 181 adults with definite TSC (mean age = 33.6 years [SD = 13.7]). More than 40% (n = 75) had family members affected by TSC. Forty-six percent (n = 83) of individuals had intellectual disability. Nearly 30% (n = 52) of individuals reported living alone or with a partner/spouse. Seventy-six percent (n = 138) of people had epilepsy, 43% (n = 59) of whom had drug-resistant epilepsy, and 21% (n = 29) had undergone epilepsy surgery. Neuropsychiatric disease (n = 128) and renal angiomyolipomas (n = 130) were both present in approximately 70% of people. Renal imaging was performed in 75.7% (n = 137) of participants within the past 3 years. Renal and pulmonary function tests, as well as electrocardiograms, were recently performed in a minority of individuals.

SIGNIFICANCE

Our cohort of adults with TSC showed that an important proportion have a milder phenotype, and are more frequently familial, as compared to children with TSC (and differing from prior reports in adult cohorts). Drug-resistant epilepsy, neuropsychiatric comorbidities, and renal angiomyolipoma are challenging factors in adults with TSC. Our participating medical centers generally followed recommended screening strategies, but there remain important gaps in care. Multidisciplinary and structured TSC care centers offering service to adults may help to improve the health of this important patient population.

COVID-19 chez les patients ontariens sous dialyse à long terme

CONTEXTE:

Les patients sous dialyse à long terme pourraient avoir un risque accru d’infection par le coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2), et de maladie et de mortalité associées. Nous avons voulu décrire l’incidence, les facteurs de risque et les issues de l’infection chez ces patients en Ontario (Canada).

MÉTHODES:

Nous avons utilisé des ensembles de données reliées pour comparer les caractéristiques de la maladie et la mortalité chez les patients sous dialyse à long terme en Ontario qui ont testé positif pour le SRAS-CoV-2 et ceux qui n’ont pas développé d’infection, entre le 12 mars et le 20 août 2020. Nous avons recueilli des données sur l’infection par le SRAS-CoV-2 de manière prospective. Nous avons évalué les facteurs de risque d’infection et de mortalité par des analyses de régression logistique multivariées.

RÉSULTATS:

Pendant la période à l’étude, 187 patients dialysés sur 12 501 (1,5 %) ont reçu un diagnostic d’infection par le SRAS-CoV-2. Parmi eux, 117 (62,6 %) ont été hospitalisés, et le taux de mortalité était de 28,3 %. Les facteurs prédictifs significatifs associés à l’infection incluaient l’hémodialyse dans un centre plutôt que la dialyse à domicile (rapport de cotes [RC] 2,54; intervalle de confiance [IC] à 95 % 1,59–4,05), le fait de vivre dans un établissement de soins de longue durée (RC 7,67; IC à 95 % 5,30–11,11), le fait d’habiter la région du Grand Toronto (RC 3,27; IC à 95 % 2,21–4,80), les ethnicités Noire (RC 3,05; IC à 95 % 1,95–4,77), du sous-continent indien (RC 1,70; IC à 95 % 1,02–2,81) et autres non blanches (RC 2,03; IC à 95 % 1,38–2,97) et les quintiles de revenu inférieurs (RC 1,82; IC à 95 % 1,15–2,89).

INTERPRÉTATION:

Les patients sous dialyse à long terme sont exposés à un risque accru d’infection par le SRAS-CoV-2 et de mortalité due à la maladie à coronavirus 2019. Il faudra travailler à éliminer les facteurs de risque d’infection et vacciner ces patients en priorité.

Autoantibodies to LG3 are associated with poor long-term survival after liver retransplantation

Autoantibodies are detrimental to the survival of organ transplantation. We demonstrated that Angiotensin II Type I Receptor agonistic autoantibodies (AT1R-AA) were associated with poor outcomes after liver retransplantation. To examine the effect of other autoantibodies, we studied a retrospective cohort of 93 patients who received a second liver transplant. Pre-retransplant sera were tested with Luminex-based solid-phase assays. Among 33 tested autoantibodies, 15 were significantly higher in 48 patients who lost their regrafts than 45 patients whose regrafts were still functioning. Specifically, patients with autoantibodies to the C-terminal laminin-like globular domain of Perlecan (LG3) experienced significantly worse regraft survival (p = .002) than those with negative LG3 autoantibodies (LG3-A). In multivariate analysis, LG3-A (HR = 2.35 [1.11-4.98], p = .027) and AT1R-AA (HR = 2.09 [1.07-4.10], p = .032) remained significant predictors of regraft loss after adjusting for recipient age and sex. There were synergistic deleterious effects on regraft survival in patients who were double-positive for LG3-A and donor-specific antibody (DSA) (HR = 5.26 [2.15-12.88], p = .001), or LG3-A and AT1R-AA (HR = 3.23 [1.37-7.66], p = .008). All six double-positive patients lost their liver regrafts. In conclusion, LG3-A is associated with inferior long-term outcomes of a second liver transplant. Screening anti-HLA antibodies and autoantibodies such as LG3-A/AT1R-AA identifies patients with a higher risk for liver transplantation.

Late-onset allograft rejection, cytomegalovirus infection, and renal allograft loss: Is anti-CMV prophylaxis required following late-onset allograft rejection?

Renal transplant recipients remain at risk of delayed-onset cytomegalovirus (CMV) infection occurring beyond a complete course of prophylaxis. In this retrospective cohort, all 278 patients who received renal allografts from deceased donors from 2014 to 2016 were followed until September 1, 2019. We determined the effect of early-vs late-onset acute rejection (EAR vs LAR [ie, occurring beyond 12 months after transplantation]) on CMV infection and subsequently long-term allograft outcome. Median (IQR) duration of follow-up was 1186.0 (904.7-1531.2) days. Seventy patients including 49 patients with EAR and 21 with LAR received augmented immunosuppression. In the same interval, 40 patients developed CMV infection (36 patients beyond 90 days after transplantation [90%]). In logistic regression analysis, D+/R- CMV serostatus (OR: 5.5, 95% CI: 2.5-12.2) and LAR (OR: 7.9, 95% CI: 2.8-22.2) significantly increased the risk of CMV infection. In Cox proportional hazard model, delayed-onset CMV infection (HR: 2.51, 95% CI: 1.08-5.86) and LAR (HR: 5.46, 95% CI: 2.26-13.14) significantly increased the risk of allograft loss. Patients with LAR are at risk of late-onset CMV infection. Post-LAR, targeted prophylaxis may reduce the risk of CMV infection and subsequently allograft loss. Further studies are required to demonstrate the effect of targeted prophylaxis following LAR.

Potential Pitfalls in Pre-implantation Genetic Diagnosis in a Patient with Tuberous Sclerosis and Isolated Mosaicism for a TSC2 Variant in Renal Tissue

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that displays a wide spectrum of clinical manifestations, often affecting multiple organs including the kidneys, brain, lungs, and skin. A pathogenic mutation in either the TSC1 or TSC2 gene can be detected in almost 85% of the cases, with mosaicism accounting for about half of the remaining cases. We report a case of TSC diagnosed clinically, requesting genetic counselling regarding reproductive risks. No mutation was identified on initial testing of peripheral blood; however, mosaicism for a likely pathogenic frameshift variant in TSC2 was detected at a level of 15% in renal angiomyolipoma tissue. Despite widespread clinical manifestations of TCS, this variant was not detected in skin fibroblasts or saliva, raising the possibility this is an isolated somatic mutation in renal tissue with the underlying germline mutation not yet identified. This case highlights the difficulties when counselling patients with mosaicism regarding their reproductive risks and prenatal diagnostic options.

COVID-19 in patients undergoing long-term dialysis in Ontario

BACKGROUND

Patients undergoing long-term dialysis may be at higher risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and of associated disease and mortality. We aimed to describe the incidence, risk factors and outcomes for infection in these patients in Ontario, Canada.

METHODS

We used linked data sets to compare disease characteristics and mortality between patients receiving long-term dialysis in Ontario who were diagnosed SARS-CoV-2 positive and those who did not acquire SARS-CoV-2 infection, between Mar. 12 and Aug. 20, 2020. We collected data on SARS-CoV-2 infection prospectively. We evaluated risk factors for infection and death using multivariable logistic regression analyses.

RESULTS

During the study period, 187 (1.5%) of 12 501 patients undergoing dialysis were diagnosed with SARS-CoV-2 infection. Of those with SARS-CoV-2 infection, 117 (62.6%) were admitted to hospital and the case fatality rate was 28.3%. Significant predictors of infection included in-centre hemodialysis versus home dialysis (odds ratio [OR] 2.54, 95% confidence interval [CI] 1.59-4.05), living in a long-term care residence (OR 7.67, 95% CI 5.30-11.11), living in the Greater Toronto Area (OR 3.27, 95% CI 2.21-4.80), Black ethnicity (OR 3.05, 95% CI 1.95-4.77), Indian subcontinent ethnicity (OR 1.70, 95% CI 1.02-2.81), other non-White ethnicities (OR 2.03, 95% CI 1.38-2.97) and lower income quintiles (OR 1.82, 95% CI 1.15-2.89).

INTERPRETATION

Patients undergoing long-term dialysis are at increased risk of SARS-CoV-2 infection and death from coronavirus disease 2019. Special attention should be paid to addressing risk factors for infection, and these patients should be prioritized for vaccination.

The effect of human leukocyte antigen A1 and B35-Cw4 on sustained BK polyomavirus DNAemia after renal transplantation

Human leukocyte antigen (HLA) class I presentation pathway plays a central role in natural killer (NK) cell and cytotoxic T-cell activities against BK polyomavirus (BKPyV) DNAemia. We determined the risk of sustained BKPyV DNAemia in 175 consecutive renal transplant recipients considering the simultaneous effect of donor/recipient HLA class I antigens and pre- or post-transplant variables. Median (IQR) age was 53 (44-64) years, and 37% of patients were female. 40 patients (22.9%) developed sustained BKPyV DNAemia [median (IQR) viral load: 9740 (4350-17 125) copies/ml]. In the Cox proportional hazard analysis, HLA-A1 (HR: 3.06, 95% CI: 1.51-6.17) and HLA-B35-Cw4 (HR: 4.63, 95% CI: 2.12-10.14) significantly increased the risk of sustained BKPyV DNAemia, while 2 HLA-C mismatches provided a marginally protective effect (HR: 0.32, 95% CI: 0.10-0.98). HLA-Cw4 is a ligand for NK cell inhibitory receptor, and HLA-B35 is in strong linkage disequilibrium with the HLA-Cw4 allele. The association between HLA-B35-Cw4 expression and sustained BKPyV DNAemia supports the important role of cytotoxic T cells and NK cells that would normally control BKPyV activation through engagement with immunoglobulin-like killer receptors (KIRs). Further studies are required to investigate the effect of HLA-C alleles along with NK cell activity against BKPyV DNAemia.

Long-lasting cluster of nosocomial pneumonia with a single Pneumocystis jirovecii genotype involving different organ allograft recipients

Pneumocystis pneumonia (PCP) outbreaks may occur in solid organ transplant (SOT) patients. Transmissibility of Pneumocystis jirovecii among SOT and non-SOT patients has not been investigated. Ten SOT (ie, 4 heart, 4 kidney, 2 liver allograft recipients) and 11 non-SOT (ie, 7 HIV-infected, 3 hematologic malignancies, and 1 stem cell transplant) patients with PCP were admitted to London Health Sciences Center (LHSC) from October 2014 to August 2016. We investigated the course of illness and outcome of PCP in SOT and non-SOT patients. Post-transplant PCP was frequently an acute-onset disease (90% vs. 18.2%, p = .01) requiring ICU admission (70% vs. 20%, p = .03) and hemodialysis (60% vs. 0, p = .003). Mortality was more frequent in SOT patients (40% vs. 18.1%, p = .36). Multilocus sequence typing (MLST) demonstrated circulation of a single genotype of P. jirovecii among SOT patients. However, 8 different genotypes were detected from non-SOT patients. Reinstitution of prophylaxis successfully controlled post-transplant cluster until end of observation period in October 2019. No transmission was detected from non-SOT patients to SOT recipients. Detection of a single P. jirovecii genotype from all SOT recipients highlights the likelihood of nosocomial transmission. No source control method is recommended by current guidelines. Improvement of preventive strategies is required.

Starch or Saline After Cardiac Surgery: A Double-Blinded Randomized Controlled Trial

Background:

Despite decades of investigation, the balance of clinical risks and benefits of fluid supplementation with starch remain unresolved. Patient-centered outcomes have not been well explored in a “real-world” trial in cardiac surgery.

Objective:

We sought to compare a starch-based fluid strategy with a saline-based fluid strategy in the cardiac surgery patient.

Design:

A pragmatic blinded randomized controlled trial comparing starch-based with saline-based fluid strategy.

Setting:

A large tertiary academic center in London Ontario between September 2009 and February 2011.

Participants:

Patients undergoing planned, isolated coronary revascularization.

Measurements:

Serum creatinine and patient weight were measured daily postoperatively.

Methods:

Patients were randomized to receive 6% hydroxyethyl starch (Voluven) or saline for perioperative fluid requirements. Fluid administration was not protocolized. Co-primary outcomes were incidence of acute kidney injury (AKI) and maximum postoperative weight gain. Secondary outcomes included bleeding, transfusion, inotropic and ventilator support, and fluid utilization.

Results:

The study was prematurely terminated due to resource limitations. A total of 69 patients (19% female, mean age = 65) were randomized. Using RIFLE criteria for AKI, “risk” occurred in 12 patients in each group (risk ratio [RR] = 1.0; 95% confidence interval [CI] = 0.5-1.9; P = 1.00), whereas “injury” occurred in 7 of 35 (20%) and 3 of 34 (9%) of patients in the starch and saline groups, respectively (RR = 2.3; 95% CI = 0.6-8.1; P = .31). Maximum weight gain, bleeding and blood product usage, and overall fluid requirement were similar between groups.

Limitations:

The study had to be prematurely terminated due to resource limitations which led to a small sample size which was not sufficiently powered to detect a difference in the primary outcomes.

Conclusions:

This pragmatic double-blinded randomized controlled trial revealed a number of interesting hypothesis-generating trends and confirmed the feasibility of undertaking a logistically complex trial in a pragmatic fashion.

Frequency, Timing, and Prediction of Major Bleeding Complications From Percutaneous Renal Biopsy

Background and Objectives:

The risk and timing of bleeding events following ultrasound-guided percutaneous renal biopsy are not clearly defined.

Design setting, participants, and measurements:

We performed a retrospective study of 617 consecutive adult patients who underwent kidney biopsy between 2012 and 2017 at a tertiary academic hospital in London, Canada. We assessed frequency and timing of minor (not requiring intervention) and major (requiring blood transfusion, surgery, or embolization) bleeds and developed a personalized risk calculator for these.

Results:

Bleeding occurred in 79 patients (12.8%; 95% confidence interval [CI]: 10.4%-15.7%). Minor bleeding occurred in 67 patients (10.9%; 95% CI: 8.6%-13.6%). Major bleeding occurred in 12 patients (1.9%; 95% CI: 1.1%-3.4%); 2 required embolization or surgery (0.3%; 95% CI: 0.09%-1.2%) and 10 required blood transfusion (1.6%; 95% CI: 0.9%-3.0%). Seventy-three of 79 events were identified immediately on post-procedure ultrasound (92.4% of cases; 95% CI: 84.4%-96.5%). Four of 617 patients experienced a minor event not detected immediately (0.6%; 95% CI: 0.3%-1.7%). Two patients (0.3%; 95% CI: 0.09%-1.2%) suffered a major complication that was not recognized immediately; both required blood transfusions only. There were no deaths or nephrectomies. A risk calculator using age, body mass index, platelet count, hemoglobin concentration, size of the target kidney, and whether the kidney is native, or an allograft predicted minor (C-statistic, 0.70) and major bleeding (C-statistic, 0.83).

Conclusions:

This retrospective study of 617 patients who had percutaneous ultrasound-guided renal biopsies supports the safety of short post-biopsy monitoring for most patients. A risk calculator can further personalize estimates of complication risk (http://perioperativerisk.com/kbrc).

Assessing Plasma Total Homocysteine in Patients with End-Stage Renal Disease

Elevated plasma total homocysteine (tHcy) is a risk factor for cardiovascular disease; however, in light of several recent randomized trials, the issue of causality has been cast into doubt. Patients with end-stage renal disease are particularly interesting as they consistently have elevated tHcy and their leading causes of morbidity and mortality are related to cardiovascular disease. In the present article, we review the early evidence for the homocysteine theory of atherosclerosis, homocysteine metabolism, mechanisms of toxicity, and pertinent available clinical investigations. Where appropriate, the sparse evidence of homocysteine in peritoneal dialysis is reviewed. We conclude by addressing the difficulties associated with lowering plasma tHcy in patients with end-stage renal disease and suggest some novel methods for lowering tHcy in this resistant population. Finally, to address the issue of causality, we recommend that clinicians and scientists await the results of the FAVORIT trial before abandoning homocysteine as a modifiable risk factor for cardiovascular disease, as this study has recruited patients from a population with consistently elevated plasma tHcy who are known to respond to vitamin therapy.

Angiotensin II type I receptor agonistic autoantibodies are associated with poor allograft survival in liver retransplantation

Angiotensin II type I receptor (AT1R) agonistic autoantibodies (AT1R-AA) are detrimental to kidney transplantation. Early studies suggested a similar negative effect in primary liver transplantation. Here, we studied AT1R-AA in a retrospective cohort of 94 patients who received a second liver transplant to determine their prevalence and effects. The concentrations of preformed AT1R-AA before transplantation were higher (P = .019) in the 48 patients who lost their liver grafts than in the 46 patients whose grafts survived. About half (48/94, 51.1%) of the patients were positive for AT1R-AA >17 U/mL before the second liver transplantation. In 22 (23.4%) patients, strong positive AT1R-AA (defined as >40 U/mL) were detected, of whom 16 (72.7%) patients lost their grafts. Based on Kaplan-Meier analysis, patients with strong positive AT1R-AA had significantly worse graft survival than those with AT1R-AA <40 U/mL (P = .035). In multivariate Cox models that included confounders such as sex and age, either AT1R-AA >40 U/mL (HR = 1.999 [1.085-3.682], P = .026) or increased concentrations of AT1R-AA (HR = 1.003 [1.001-1.006] per incremental U/mL, P = .019) were significantly associated with elevated risk for graft loss. In conclusion, our data indicate that there is a high prevalence of AT1R-AA in candidates for second liver transplantation and that their presence is associated with inferior long-term outcomes of the second graft.

Untargeted metabolomics reveals N, N, N-trimethyl-L-alanyl-L-proline betaine (TMAP) as a novel biomarker of kidney function

The diagnosis and prognosis of chronic kidney disease (CKD) currently relies on very few circulating small molecules, which can vary by factors unrelated to kidney function. In end-stage renal disease (ESRD), these same small molecules are used to determine dialysis dose and dialytic clearance. Therefore, we aimed to identify novel plasma biomarkers to estimate kidney function in CKD and dialytic clearance in ESRD. Untargeted metabolomics was performed on plasma samples from patients with a single kidney, non-dialysis CKD, ESRD and healthy controls. For ESRD patients, pre- and post-dialysis plasma samples were obtained from several dialysis modalities. Metabolomics analysis revealed over 400 significantly different features in non-dialysis CKD and ESRD plasma compared to controls while less than 35 features were significantly altered in patients with a single kidney. N,N,N-trimethyl-L-alanyl-L-proline betaine (TMAP, AUROC = 0.815) and pyrocatechol sulfate (AUROC = 0.888) outperformed creatinine (AUROC = 0.745) in accurately identifying patients with a single kidney. Several metabolites accurately predicted ESRD; however, when comparing pre-and post-hemodialysis, TMAP was the most robust biomarker of dialytic clearance for all modalities (AUROC = 0.993). This study describes TMAP as a novel potential biomarker of kidney function and dialytic clearance across several hemodialysis modalities.

Arterial Stiffness in the Heart Disease of CKD

CKD frequently leads to chronic cardiac dysfunction. This complex relationship has been termed as cardiorenal syndrome type 4 or cardio-renal link. Despite numerous studies and reviews focused on the pathophysiology and therapy of this syndrome, the role of arterial stiffness has been frequently overlooked. In this regard, several pathogenic factors, including uremic toxins (i.e., uric acid, phosphates, endothelin-1, advanced glycation end-products, and asymmetric dimethylarginine), can be involved. Their effect on the arterial wall, direct or mediated by chronic inflammation and oxidative stress, results in arterial stiffening and decreased vascular compliance. The increase in aortic stiffness results in increased cardiac workload and reduced coronary artery perfusion pressure that, in turn, may lead to microvascular cardiac ischemia. Conversely, reduced arterial stiffness has been associated with increased survival. Several approaches can be considered to reduce vascular stiffness and improve vascular function in patients with CKD. This review primarily discusses current understanding of the mechanisms concerning uremic toxins, arterial stiffening, and impaired cardiac function, and the therapeutic options to reduce arterial stiffness in patients with CKD.

Heart failure in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

The incidence and prevalence of heart failure (HF) and chronic kidney disease (CKD) are increasing, and as such a better understanding of the interface between both conditions is imperative for developing optimal strategies for their detection, prevention, diagnosis, and management. To this end, Kidney Disease: Improving Global Outcomes (KDIGO) convened an international, multidisciplinary Controversies Conference titled Heart Failure in CKD. Breakout group discussions included (i) HF with preserved ejection fraction (HFpEF) and nondialysis CKD, (ii) HF with reduced ejection fraction (HFrEF) and nondialysis CKD, (iii) HFpEF and dialysis-dependent CKD, (iv) HFrEF and dialysis-dependent CKD, and (v) HF in kidney transplant patients. The questions that formed the basis of discussions are available on the KDIGO website http://kdigo.org/conferences/heart-failure-in-ckd/, and the deliberations from the conference are summarized here.

Albuminuria and Allograft Failure, Cardiovascular Disease Events, and All-Cause Death in Stable Kidney Transplant Recipients: A Cohort Analysis of the FAVORIT Trial

RATIONALE & OBJECTIVE

Cardiovascular disease (CVD) is common and overall graft survival is suboptimal among kidney transplant recipients. Although albuminuria is a known risk factor for adverse outcomes among persons with native chronic kidney disease, the relationship of albuminuria with cardiovascular and kidney outcomes in transplant recipients is uncertain.

STUDY DESIGN

Post hoc longitudinal cohort analysis of the Folic Acid for Vascular Outcomes Reduction in Transplantation (FAVORIT) Trial.

SETTING & PARTICIPANTS

Stable kidney transplant recipients with elevated homocysteine levels from 30 sites in the United States, Canada, and Brazil.

PREDICTOR

Urine albumin-creatinine ratio (ACR) at randomization.

OUTCOMES

Allograft failure, CVD, and all-cause death.

ANALYTICAL APPROACH

Multivariable Cox models adjusted for age; sex; race; randomized treatment allocation; country; systolic and diastolic blood pressure; history of CVD, diabetes, and hypertension; smoking; cholesterol; body mass index; estimated glomerular filtration rate (eGFR); donor type; transplant vintage; medications; and immunosuppression.

RESULTS

Among 3,511 participants with complete data, median ACR was 24 (Q1-Q3, 9-98) mg/g, mean eGFR was 49±18 (standard deviation) mL/min/1.73m², mean age was 52±9 years, and median graft vintage was 4.1 (Q1-Q3, 1.7-7.4) years. There were 1,017 (29%) with ACR < 10mg/g, 912 (26%) with ACR of 10 to 29mg/g, 1,134 (32%) with ACR of 30 to 299mg/g, and 448 (13%) with ACR ≥ 300mg/g. During approximately 4 years, 282 allograft failure events, 497 CVD events, and 407 deaths occurred. Event rates were higher at both lower eGFRs and higher ACR. ACR of 30 to 299 and ≥300mg/g relative to ACR < 10mg/g were independently associated with graft failure (HRs of 3.40 [95% CI, 2.19-5.30] and 9.96 [95% CI, 6.35-15.62], respectively), CVD events (HRs of 1.25 [95% CI, 0.96-1.61] and 1.55 [95% CI, 1.13-2.11], respectively), and all-cause death (HRs of 1.65 [95% CI, 1.23-2.21] and 2.07 [95% CI, 1.46-2.94], respectively).

LIMITATIONS

No data for rejection; single ACR assessment.

CONCLUSIONS

In a large population of stable kidney transplant recipients, elevated baseline ACR is independently associated with allograft failure, CVD, and death. Future studies are needed to evaluate whether reducing albuminuria improves these outcomes.

Effect of Coaching to Increase Water Intake on Kidney Function Decline in Adults With Chronic Kidney Disease: The CKD WIT Randomized Clinical Trial

IMPORTANCE

In observational studies, increased water intake is associated with better kidney function.

OBJECTIVE

To determine the effect of coaching to increase water intake on kidney function in adults with chronic kidney disease.

DESIGN, SETTING, AND PARTICIPANTS

The CKD WIT (Chronic Kidney Disease Water Intake Trial) randomized clinical trial was conducted in 9 centers in Ontario, Canada, from 2013 until 2017 (last day of follow-up, May 25, 2017). Patients had stage 3 chronic kidney disease (estimated glomerular filtration rate [eGFR] 30-60 mL/min/1.73 m2 and microalbuminuria or macroalbuminuria) and a 24-hour urine volume of less than 3.0 L.

INTERVENTIONS

Patients in the hydration group (n = 316) were coached to drink more water, and those in the control group (n = 315) were coached to maintain usual intake.

MAIN OUTCOMES AND MEASURES

The primary outcome was change in kidney function (eGFR from baseline to 12 months). Secondary outcomes included 1-year change in plasma copeptin concentration, creatinine clearance, 24-hour urine albumin, and patient-reported overall quality of health (0 [worst possible] to 10 [best possible]).

RESULTS

Of 631 randomized patients (mean age, 65.0 years; men, 63.4%; mean eGFR, 43 mL/min/1.73 m2; median urine albumin, 123 mg/d), 12 died (hydration group [n = 5]; control group [n = 7]). Among 590 survivors with 1-year follow-up measurements (95% of 619), the mean change in 24-hour urine volume was 0.6 L per day higher in the hydration group (95% CI, 0.5 to 0.7; P < .001). The mean change in eGFR was -2.2 mL/min/1.73 m2 in the hydration group and -1.9 mL/min/1.73 m2 in the control group (adjusted between-group difference, -0.3 mL/min/1.73 m2 [95% CI, -1.8 to 1.2; P = .74]). The mean between-group differences (hydration vs control) in secondary outcomes were as follows: plasma copeptin, -2.2 pmol/L (95% CI, -3.9 to -0.5; P = .01); creatinine clearance, 3.6 mL/min/1.73 m2 (95% CI, 0.8 to 6.4; P = .01); urine albumin, 7 mg per day (95% CI, -4 to 51; P = .11); and quality of health, 0.2 points (95% CI, -0.3 to 0.3; P = .22).

CONCLUSIONS AND RELEVANCE

Among adults with chronic kidney disease, coaching to increase water intake compared with coaching to maintain the same water intake did not significantly slow the decline in kidney function after 1 year. However, the study may have been underpowered to detect a clinically important difference.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01766687.

The Chronic Kidney Disease Water Intake Trial: Protocol of a Randomized Controlled Trial

Background:

In observational studies, drinking more water associates with a slower rate of kidney function decline; whether the same is true in a randomized controlled trial is unknown.

Objective:

To examine the 1-year effect of a higher vs usual water intake on estimated glomerular filtration rate (eGFR) in patients with chronic kidney disease.

Design:

Parallel-group randomized controlled trial.

Setting:

Nine centers in Ontario, Canada. Enrollment and randomization occurred between May 2013 and May 2016; follow-up for the primary outcome will continue until June 2017.

Participants:

Adults (n = 631) with stage 3 chronic kidney disease (eGFR 30-60 mL/min/1.73 m²) and microalbuminuria.

Intervention:

The high water intake group was coached to increase their oral water intake by 1.0 to 1.5 L/day (depending on sex and weight), over and above usual consumed beverages, for a period of 1 year. The control group was coached to maintain their usual water intake during this time.

Measures:

Participants provided 24-hour urine samples at baseline and at 6 and 12 months after randomization; urine samples were analyzed for volume, creatinine, osmolality, and the albumin-to-creatinine ratio. Blood samples were obtained at baseline and at 3- to 6-month intervals after randomization, and analyzed for creatinine, copeptin, osmolality, and electrolytes. Other measures collected included health-related quality of life, blood pressure, body mass index, and diet.

Primary outcome:

The between-group change in eGFR from baseline (prerandomization) to 12 months after randomization.

Secondary outcomes:

Change in plasma copeptin concentration, 24-hour urine albumin-to-creatinine ratio, measured creatinine clearance, estimated 5-year risk of kidney failure (using the 4-variable Kidney Failure Risk Equation), and health-related quality of life.

Planned analysis:

The primary analysis will follow an intention-to-treat approach. The between-group change in eGFR will be compared using linear regression. Supplementary analyses will examine alternative definitions of eGFR change, including annual percentage change, rate of decline, and rapid decline (a P value <0.05 will be interpreted as statistically significant if there is concordance with the primary outcome).

Trial Registration:

This randomized controlled trial has been registered at www.clinicaltrials.gov; government identifier: NCT01766687.

Characteristics and Outcomes of Patients Discharged Home from an Emergency Department with AKI

BACKGROUND AND OBJECTIVES

Patients discharged home from an emergency department with AKI are not well described. This study describes their characteristics and outcomes and compares these outcomes to two referent groups.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a population-based retrospective cohort study in Ontario, Canada from 2003 to 2012 of 6346 patients aged ≥40 years who were discharged from the emergency department with AKI (defined using serum creatinine values). We analyzed the risk of all-cause mortality, receipt of acute dialysis, and hospitalization within 30 days after discharge. We used propensity score methods to compare all-cause mortality to two referent groups. We matched 4379 discharged patients to 4379 patients who were hospitalized from the emergency department with similar AKI stage. We also matched 6188 discharged patients to 6188 patients who were discharged home from the emergency department with no AKI.

RESULTS

There were 6346 emergency department discharges with AKI. The mean age was 69 years and 6012 (95%) had stage 1, 290 (5%) had stage 2, and 44 (0.7%) had stage 3 AKI. Within 30 days, 149 (2%) (AKI stage 1: 127 [2%]; stage 2: 15 [5%]; stage 3: seven [16%]) died, 22 (0.3%) received acute dialysis, and 1032 (16%) were hospitalized. An emergency department discharge versus hospitalization with AKI was associated with lower mortality (3% versus 12%; relative risk, 0.3; 95% confidence interval, 0.2 to 0.3). An emergency department discharge with AKI versus no AKI was associated with higher mortality (2% versus 1%; relative risk, 1.6; 95% confidence interval, 1.2 to 2.0).

CONCLUSIONS

Patients discharged home from the emergency department with AKI are at risk of poor 30-day outcomes. A better understanding of care in this at-risk population is warranted, as are testing strategies to improve care.

CRRTnet: a prospective, multi-national, observational study of continuous renal replacement therapy practices

Background

Continuous renal replacement therapy (CRRT) is the recommended modality of dialysis for critically ill patients with hemodynamic instability. Yet there remains significant variability in how CRRT is prescribed and delivered, and limited evidence-basis to guide practice.

Methods

This is a prospective, multi-center observational study of patients undergoing CRRT. Initial enrollment phase will occur at 4 academic medical centers in North America over 5 years, with a target enrollment of 2000 patients. All adult patients (18–89 years of age) receiving CRRT will be eligible for inclusion; patients who undergo CRRT for less than 24 h will be excluded from analysis. Data collection will include patient characteristics at baseline and at time of CRRT initiation; details of CRRT prescription and delivery, including machine-generated treatment data; and patient outcomes.

Discussion

The goal of this study is to establish a large comprehensive registry of critically ill adults receiving CRRT. Specific aims include describing variations in CRRT prescription and delivery across quality domains; validating quality measures for CRRT care by correlating processes and outcomes; and establishing a large registry for use in quality improvement and benchmarking efforts. For initial analyses, some particular areas of interest are anticoagulation protocols; approach to fluid overload; CRRT-related workload; and patient safety.

Trial registration

Registered on ClinicalTrials.gov 1/10/2014: NCT02034448.

Serum Phosphorus and Risk of Cardiovascular Disease, All-Cause Mortality, or Graft Failure in Kidney Transplant Recipients: An Ancillary Study of the FAVORIT Trial Cohort

BACKGROUND

Mild hyperphosphatemia is a putative risk factor for cardiovascular disease [CVD], loss of kidney function, and mortality. Very limited data are available from sizable multicenter kidney transplant recipient (KTR) cohorts assessing the potential relationships between serum phosphorus levels and the development of CVD outcomes, transplant failure, or all-cause mortality.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

The Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial, a large, multicenter, multiethnic, controlled clinical trial that provided definitive evidence that high-dose vitamin B-based lowering of plasma homocysteine levels did not reduce CVD events, transplant failure, or total mortality in stable KTRs.

PREDICTOR

Serum phosphorus levels were determined in 3,138 FAVORIT trial participants at randomization.

RESULTS

During a median follow-up of 4.0 years, the cohort had 436 CVD events, 238 transplant failures, and 348 deaths. Proportional hazards modeling revealed that each 1-mg/dL higher serum phosphorus level was not associated with a significant increase in CVD risk (HR, 1.06; 95% CI, 0.92-1.22), but increased transplant failure (HR, 1.36; 95% CI, 1.15-1.62) and total mortality risk associations (HR, 1.21; 95% CI, 1.04-1.40) when adjusted for treatment allocation, traditional CVD risk factors, kidney measures, type of kidney transplant, transplant vintage, and use of calcineurin inhibitors, steroids, or lipid-lowering drugs. These associations were strengthened in models without kidney measures: CVD (HR, 1.14; 95% CI, 1.00-1.31), transplant failure (HR, 1.72; 95% CI, 1.46-2.01), and mortality (HR, 1.34; 95% CI, 1.15-1.54).

LIMITATIONS

We lacked data for concentrations of parathyroid hormone, fibroblast growth factor 23, or vitamin D metabolites.

CONCLUSIONS

Serum phosphorus level is marginally associated with CVD and more strongly associated with transplant failure and total mortality in long-term KTRs. A randomized controlled clinical trial in KTRs that assesses the potential impact of phosphorus-lowering therapy on these hard outcomes may be warranted.

The Risk of Acute Rejection Following Kidney Transplant by 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Status: A Prospective Cohort Study

Background:

Prediction of acute kidney transplant rejection remains imperfect despite several known risk factors. There is an increasing appreciation of the potential importance of the vitamin D pathway in immunological disease and transplantation.

Objective:

The purpose of this study was to determine the association of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D with acute rejection.

Design:

This was a prospective cohort study.

Setting:

Three academic adult kidney transplant programs in Ontario, Canada, were chosen.

Patients:

All consecutive adult patients at the 3 institutions who received a solitary kidney transplant, were able to provide written informed consent, and planned to be followed at the same center post-operatively were included.

Measurements:

Serum concentration of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured at baseline, 3, and 6 months post-transplantation. Acute rejection was classified using Banff criteria.

Methods:

The co-primary outcome was the association between 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D and time to first occurrence of biopsy-proven acute rejection (BPAR) within the first year after kidney transplantation. Cox proportional hazards models were fitted taking into account the time-varying nature of serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D.

Results:

From 556 screened patients, data on 327 kidney transplant recipients are included. First BPAR occurred in 54 (16.5%) patients. In adjusted Cox proportional hazards models, the serum concentration of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D was not associated with acute renal transplant rejection (hazard ratio 1.00; 95% [confidence interval] CI, 0.87-1.14, per 10 nmol/L increase, and hazard ratio 0.97; 95% CI, 0.84-1.12, per 10 pmol/L increase, respectively).

Limitations:

Given the observational design, we cannot rule out the possibility of residual confounding that limited our ability to detect a clinically significant effect of vitamin D metabolites on acute rejection.

Conclusions:

A low serum concentration of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D is not associated with an increased risk of acute kidney transplant rejection following kidney transplantation.

Hemodialysis Infection Prevention Protocols Ontario-Shower Technique (HIPPO-ST): A Pilot Randomized Trial

INTRODUCTION

We developed the Hemodialysis Infection Prevention Protocols Ontario-Shower Technique (HIPPO-ST) to permit hemodialysis (HD) patients with central venous catheters (catheters) to shower without additional infection risk. Our primary objective was to determine the feasibility of conducting a parallel randomized controlled trial (RCT) to evaluate the impact of HIPPO-ST on catheter-related bacteremia (CRB) in adult HD patients.

METHODS

Adult HD patients using catheters were recruited from 11 HD units. Patients were randomized to receive HIPPO-ST or standard care and were followed up for 6 months. Only CRB-outcome assessors were blinded. For the study to be considered feasible, 4 of 5 feasibility outcomes, each with its own statistical threshold for success, must have been achieved.

RESULTS

A total of 68 patients were randomized (33 HIPPO-ST and 35 control) and were followed up to 6 months. Of 5 measures of feasibility, 4 were achieved: (1) accurate CRB rate documented (threshold: κ level >0.80); (2) 97.8% (279/285) of satellite HD patients with catheters were screened (threshold: >95%); (3) 88% (23/26) in the HIPPO-ST arm were successfully educated by 6 months (threshold: >80%); and (4) 0% (0/29) patients in the control arm were "contaminated," that is, using HIPPO-ST (threshold: <5%). However, only 44.2% (72/163) of eligible patients consented to participate (threshold: >80%). The rate of CRB was similarly low in HIPPO-ST and control groups (0.68 vs. 0.88/1000 catheter days).

DISCUSSION

This HIPPO-ST pilot study demonstrated the feasibility of the larger HIPPO-ST study, especially given the high levels of education success with the HIPPO-ST arm and the low levels of contamination in the control arm.

Primary Epstein-Barr virus infection, seroconversion, and post-transplant lymphoproliferative disorder in seronegative renal allograft recipients: a prospective cohort study

BACKGROUND

Epstein-Barr virus (EBV)-seronegative renal transplant recipients are at risk of post-transplant lymphoproliferative disorder (PTLD). We compared primary EBV infection, seroconversion, and PTLD in EBV-seronegative patients who received renal allograft from seropositive or seronegative donors (D+/R- and D-/R-, respectively).

METHODS

We prospectively followed 25 D+/R- and 8 D-/R- recipients. We followed patients from January 1999 to June 2009 with clinical visits, monthly EBV polymerase chain reaction tests, and serologic tests for a period of 1 year after kidney transplantation and on an individual basis thereafter.

RESULTS

Three patients (9%) developed PTLD including 2 early-onset (<12 months) and 1 late-onset (>12 months) disease. In D+/R- and D-/R- patients, the frequencies of PTLD (8% vs. 12.5%, P = 0.7), EBV seroconversion (64% vs. 50%, P = 0.4), and EBV viremia (40% vs. 25%, P = 0.6) were not significantly different. Clinical, serologic, and virologic surveillance as well as reduction in immunosuppression after evidence of primary EBV infection resulted in a PTLD rate of 9%, despite a seroconversion rate of 60.6%. Rate of graft loss after reduction in immunosuppression was 10% (2 of 20), which was not significantly different from 13 patients without EBV seroconversion (no graft loss, P = 0.5). Rates of viremia, seroconversion, and PTLD in D+/R- and D-/R- patients appear to be similar.

CONCLUSIONS

The incidence of PTLD in renal transplants ranges from 0.5% to 2.9%. Our data show a significantly higher rate in EBV-seronegative renal allograft recipients, suggesting the need for close surveillance. Our data also suggest that donors for EBV-seronegative recipients may be accepted irrespective of positive or negative serostatus, with ongoing surveillance important in either circumstance.

Drug Disposition Issues in CKD: Implications for Drug Discovery and Regulatory Approval

Patients with chronic kidney disease (CKD) have several comorbidities that require pharmacologic intervention including hypertension, diabetes, anemia, and cardiovascular disease. Advanced CKD patients (eg, treated with hemodialysis) take an average of 12 medications concurrently and are known to suffer from an increased number of medication-related adverse drug events. Recent basic and clinical research has identified altered renal and nonrenal drug clearance in CKD as one mediator of the increased adverse drug events observed in this patient population. This review will briefly describe pharmacokinetic considerations in CKD, review the Food and Drug Administration guidelines for performing pharmacokinetic studies in CKD patients, and outline the roles of academia, industry, and regulatory agencies in improving drug safety in CKD patients.

Effect of increased water intake on plasma copeptin in patients with chronic kidney disease: results from a pilot randomised controlled trial

OBJECTIVES

Increased water intake may have a beneficial effect on the kidney through suppression of plasma vasopressin. We examined the effect of increased water intake on plasma copeptin (a marker of vasopressin) over 6 weeks in patients with chronic kidney disease.

DESIGN

Secondary analysis of a randomised controlled parallel-group pilot trial.

SETTING

Canada, 2012-2013.

PARTICIPANTS

28 patients with stage 3 chronic kidney disease randomised (2:1) to a hydration (n=17) or control group (n=11).

INTERVENTION

The hydration group was coached to increase water intake by up to 1.5 L/day for 6 weeks. The control group was asked to maintain regular water intake.

MEASURES AND OUTCOMES

Participants provided blood and 24 h urine samples at baseline and 6 weeks. Change in plasma copeptin was compared within and between study groups.

RESULTS

Participants were 64% male with a mean age of 62 years and an estimated glomerular filtration rate of 40 mL/min/1.73 m(2). Between baseline and 6 weeks, 24 h urine volume increased by 0.7 L/day in the hydration group, rising from 2.3 to 3.0 L/day (p=0.01), while decreasing by 0.3 L/day among controls, from 2.0 to 1.7 L/day (p=0.07); between-group difference: 0.9 L/day (95% CI 0.37 to 1.46; p=0.002). In the hydration group, median copeptin decreased by 3.6 pmol/L, from 15.0 to 10.8 pmol/L (p=0.005), while remaining stable among controls at 19 pmol/L (p=0.76; p=0.19 for the between-group difference in median change); the between-group difference in mean change was 5.4 pmol/L (95% CI -1.2 to 12.0; p=0.11).

CONCLUSIONS

Adults with stage 3 chronic kidney disease can be successfully randomised to drink approximately 1 L more per day than controls. This increased water intake caused a significant decrease in plasma copeptin concentration. Our larger 12-month trial will examine whether increased water intake can slow renal decline in patients with chronic kidney disease.

TRIAL REGISTRATION NUMBER

NCT01753466.

The (99m)Tc-DTPA urinary clearance method may be preferable to the plasma disappearance method for assessing glomerular filtration rate in diabetic nephropathy

BACKGROUND

Isotopic glomerular filtration rate (iGFR) measurement is comparable to the inulin method. In this study, we compared urinary and plasma iGFR methodologies in patients with diabetic nephropathy.

METHODS

A total of 147 patients from 3 sites in the Diabetic Intervention with Vitamins to Improve Nephropathy (DIVINe) trial provided 213 sets of urine and blood collections, at baseline, 18 and 36 months.

RESULTS

The mean (with standard deviation) plasma iGFR of 60.7 (24.9) ml/min/1.73 m(2) compared to urinary iGFR of 52.0 (28.0) ml/min/1.73 m(2) was statistically significant (p value <0.001). Although plasma and urinary iGFRs were highly related (R(2) = 0.86), plasma iGFR increasingly overestimated urinary iGFRs at lower GFRs. In contrast to the cross-sectional analyses, the two measures of iGFR were weakly related (R(2) = 0.32) in regard to patients' change over 18 months of follow-up.

CONCLUSION

Plasma iGFR may not be a suitable method for accurately measuring GFR in patients with advancing degrees of chronic kidney disease from diabetic nephropathy.

Association between muscle hydration measures acquired using bioelectrical impedance spectroscopy and magnetic resonance imaging in healthy and hemodialysis population

Establishing the effect of fluctuating extracellular fluid (ECF) volume on muscle strength in people with end-stage renal disease (ESRD) on hemodialysis (HD) is essential, as inadequate hydration of the skeletal muscles impacts its strength and endurance. Bioelectrical impedance spectroscopy (BIS) has been a widely used method for estimating ECF volume of a limb or calf segment. Magnetic resonance imaging (MRI)-acquired transverse relaxation times (T2) has also been used for estimating ECF volumes of individual skeletal muscles. The purpose of this study was to determine the association between T2 (gold standard) of tibialis anterior (TA), medial (MG), and lateral gastrocnemius (LG), and soleus muscles and calf BIS ECF, in healthy and in people with ESRD/HD. Calf BIS and MRI measures were collected on two occasions before and after HD session in people with ESRD/HD and on a single occasion for the healthy participants. Linear regression analysis was used to establish the association between these measures. Thirty-two healthy and 22 participants on HD were recruited. The association between T2 of TA, LG, MG, and soleus muscles and ratio of calf BIS-acquired ECF and intracellular fluids (ICF) were: TA: β = 0.30, P > 0.05; LG: β = 0.37, P = 0.035; MG: β = 0.43, P = 0.014; soleus: β = 0.60, P < 0.001. For the HD group, calf ECF was significantly associated with T2 of TA (β = 0.44, P = 0.042), and medial gastrocnemius (β = 0.47, P = 0.027) following HD only. Hence BIS-acquired measures cannot be used to measure ECF volumes of a single muscle in the ESRD/HD population; however, BIS could be utilized to estimate ratio of ECF: ICF in healthy population for the LG, MG, and soleus muscles.

Levofloxacin for BK virus prophylaxis following kidney transplantation: a randomized clinical trial

IMPORTANCE

BK virus infection is a significant complication of modern immunosuppression used in kidney transplantation. Viral reactivation occurs first in the urine (BK viruria) and is associated with a high risk of transplant failure. There are currently no therapies to prevent or treat BK virus infection. Quinolone antibiotics have antiviral properties against BK virus but efficacy at preventing this infection has not been shown in prospective controlled studies.

OBJECTIVE

To determine if levofloxacin can prevent BK viruria in kidney transplant recipients.

DESIGN, SETTING, AND PARTICIPANTS

Double-blind, placebo-controlled randomized trial involving 154 patients who received a living or deceased donor kidney-only transplant in 7 Canadian transplant centers between December 2011 and June 2013.

INTERVENTIONS

Participants were randomly assigned to receive a 3-month course of levofloxacin (500 mg/d; n = 76) or placebo (n = 78) starting within 5 days after transplantation.

MAIN OUTCOMES AND MEASURES

The primary outcome was time to occurrence of BK viruria (detected using quantitative real-time polymerase chain reaction) within the first year after transplantation. Secondary outcomes included BK viremia, peak viral load, rejection, and patient and allograft survival.

RESULTS

The mean follow-up time was 46.5 weeks in the levofloxacin group and 46.3 weeks in the placebo group (27 patients had follow-up terminated before the end of the planned follow-up period or development of viruria because the trial was stopped early owing to lack of funding). BK viruria occurred in 22 patients (29%) in the levofloxacin group and in 26 patients (33.3%) in the placebo group (hazard ratio, 0.91; 95% CI, 0.51-1.63; P = .58). There was no significant difference between the 2 groups in regard to any of the secondary end points. There was an increased risk of resistant infection among isolates usually sensitive to quinolones in the levofloxacin group vs placebo (14/24 [58.3%] vs 15/45 [33.3%], respectively; risk ratio, 1.75; 95% CI, 1.01-2.98) as well as a nonsignificant increased risk of suspected tendinitis (6/76 [7.9%] vs 1/78 [1.3%]; risk ratio, 6.16; 95% CI, 0.76-49.95).

CONCLUSIONS AND RELEVANCE

Among kidney transplant recipients, a 3-month course of levofloxacin initiated early following transplantation did not prevent BK viruria. Levofloxacin was associated with an increased risk of adverse events such as bacterial resistance. These findings do not support the use of levofloxacin to prevent posttransplant BK virus infection.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01353339.

Preoperative Cylex assay predicts rejection risk in patients with kidney transplant

INTRODUCTION AND OBJECTIVES

The ImmuKnow assay measures cell-mediated immunity by quantifying ATP release from CD4+ T-cells in peripheral blood. Herein, we hypothesized that this assay could predict complications associated with over-/under-immunosuppression in patients with kidney transplant (KT).

METHODS

Sixty-seven patients undergoing KT were recruited prospectively and had ATP levels measured preoperatively, and at specified intervals over two months. Clinicians were blinded to ATP levels. Clinical events including rejection and infection/cancer were documented with a median follow-up of 21 months. Parameters including absolute ATP levels and changes in ATP patterns (slopes, delta) were analyzed. Association between ATP parameters and clinical outcomes was compared using the likelihood-ratio test and Kaplan-Meier curves.

RESULTS

Absolute ATP values postoperatively had poor predictive value with regard to rejection or infection/malignancy. As well, changes in ATP values were poorly associated with complications. Importantly, patients with pre-transplant ATP values <300 ng/mL had significantly less rejection episodes vs. those with ATP values >300 ng/mL (p < 0.0001).

CONCLUSIONS

For the first time, we have evidence that a preoperative ImmuKnow level can stratify patients with KT into low/high risk groups for rejection. Future studies used to assess the utility of this assay to design individualized immunosuppressive regimens are required.

Anabolic Effect of Exercise Training in People with End-Stage Renal Disease on Hemodialysis: A Systematic Review with Meta-analysis

PURPOSE

The primary purpose of this systematic review was to evaluate the anabolic effect of exercise intervention in adults with end-stage renal disease on hemodialysis (HD). The secondary objectives were to evaluate the influences of participant characteristics and exercise parameters on changes in muscle size.

METHODS

Electronic databases (Cochrane, CINAHL, EMBASE, PEDro, PubMed and SCOPUS) were searched from inception to November 2012. Randomized clinical trials published in English that included adults on HD undergoing an exercise intervention where muscle mass was measured as an outcome were included in this review. Two reviewers independently selected the studies, extracted data, and assessed risk of bias within the included studies. RESULTS were then combined by meta-analysis. The effect of exercises was determined using a standardized mean difference (SMD), expressed as Hedges' g, computed using a random effects model.

RESULTS

Seven SMDs extracted from five studies were included for final analysis. Strength training was used in all studies; one study used aerobic and mixed strength and aerobic training with two subgroups of participants. The overall effect of exercise on muscle mass was statistically significant (SMD: 0.272; 95% CI, 0.020-0.525).

CONCLUSIONS

Our results confirm a small but significant effect of strengthening exercise as an anabolic intervention to increase muscle mass. Exercise training should be included in routine management of people on maintenance HD. Although current results indicate that one in nine people on HD is likely to benefit from exercise intervention, parameters influencing these results require further research.

The chronic kidney disease Water Intake Trial (WIT): results from the pilot randomised controlled trial

BACKGROUND AND OBJECTIVES

Increased water intake may benefit kidney function. Prior to initiating a larger randomised controlled trial (RCT), we examined the safety and feasibility of asking adults with chronic kidney disease (CKD) to increase their water intake.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

Beginning in October 2012, we randomly assigned 29 adults with stage 3 CKD (estimated glomerular filtration rate (eGFR) 30-60 mL/min/1.73 m(2) and albuminuria) to one of the two groups of water intake: hydration (n=18) or standard (n=11). We asked the hydration group to increase their water intake by 1.0-1.5 L/day (in addition to usual intake, depending on sex and weight) for 6 weeks, while the control group carried on with their usual intake. Participants collected a 24 h urine sample at baseline and at 2 and 6 weeks after randomisation. Our primary outcome was the between-group difference in change in 24 h urine volume from baseline to 6 weeks.

RESULTS

(63%)of participants were men, 81% were Caucasians and the average age was 61 years (SD 14 years). The average baseline eGFR was 40 mL/min/1.73 m(2) (SD 11 mL/min/1.73 m(2)); the median albumin to creatinine ratio was 19 mg/mmol (IQR 6-74 mg/mmol). Between baseline and 6-week follow-up, the hydration group's average 24 h urine volume increased by 0.7 L/day (from 2.3 to 3.0 L/day) and the control group's 24 h urine decreased by 0.3 L/day (from 2.0 to 1.7 L/day; between-group difference in change: 0.9 L/day (95% CI 0.4 to 1.5; p=0.002)). We found no significant changes in urine, serum osmolality or electrolyte concentrations, or eGFR. No serious adverse events or changes in quality of life were reported.

CONCLUSIONS

A pilot RCT indicates adults with stage 3 CKD can successfully and safely increase water intake by up to 0.7 L/day in addition to usual fluid intake. TRIAL REGISTRATION REGISTERED WITH CLINICAL TRIALSGOVERNMENT IDENTIFIER: NCT01753466.

Cardiorenal syndrome: new developments in the understanding and pharmacologic management

Cardiorenal syndromes (CRSs) with bidirectional heart-kidney signaling are increasingly being recognized for their association with increased morbidity and mortality. In acute CRS, recognition of the importance of worsening kidney function complicating management of acute decompensated heart failure has led to the examination of this specific outcome in the context of acute heart failure clinical trials. In particular, the role of fluid overload and venous congestion has focused interest in the most effective use of diuretic therapy to relieve symptoms of heart failure while at the same time preserving kidney function. Additionally, many novel vasoactive therapies have been studied in recent years with the hopes of augmenting cardiac function, improving symptoms and patient outcomes, while maintaining or improving kidney function. Similarly, recent advances in our understanding of the pathophysiology of chronic CRS have led to reanalysis of kidney outcomes in pivotal trials in chronic congestive heart failure, and newer trials are including changes in kidney function as well as kidney injury biomarkers as prospectively monitored and adjudicated outcomes. This paper provides an overview of some new developments in the pharmacologic management of acute and chronic CRS, examines several reports that illustrate a key management principle for each subtype, and discusses opportunities for future research.

Quinolone prophylaxis for the prevention of BK virus infection in kidney transplantation: study protocol for a randomized controlled trial

BACKGROUND

BK virus infection has emerged as a major complication in kidney transplantation leading to a significant reduction in graft survival. There are currently no proven strategies to prevent or treat BK virus infection. Quinolone antibiotics, such as levofloxacin, have demonstrated activity against BK virus. We hypothesize that administration of a quinolone antibiotic, when given early post-transplantation, will prevent the establishment of BK viral replication in the urine and thus prevent systemic BK virus infection.

METHODS/DESIGN

The aim of this pilot trial is to assess the efficacy, safety and feasibility of a 3-month course of levofloxacin in the kidney transplant population. This is a multicenter, randomized, double-blind, placebo-controlled trial with two parallel arms conducted in 11 Canadian kidney transplant centers. A total of 154 patients with end-stage renal disease undergoing kidney transplantation will be randomized to receive a 3-month course of levofloxacin or placebo starting in the early post-transplant period. Levofloxacin will be administered at 500 mg po daily with dose adjustments based on kidney function. The primary outcome will be the time to occurrence of BK viruria within the first year post-transplantation. Secondary outcomes include BK viremia, measures of safety (adverse events, resistant infections,Clostridium difficile-associated diarrhea), measures of feasibility (proportion of transplanted patients recruited into the trial), proportion of patients adherent to the protocol, patient drop-out and loss to follow-up,and use of quinolone antibiotics outside of the trial protocol.

DISCUSSION

Results from this pilot study will provide vital information to design and conduct a large, multicenter trial to determine if quinolone therapy decreases clinically meaningful outcomes in kidney transplantation. If levofloxacin significantly reduces BK viruria and urine viral loads in kidney transplantation, it will provide important justification to progress to the larger trial. If the full trial shows that levofloxacin significantly reduces BK infection and improves outcomes, its use in kidney transplantation will be strongly endorsed given the lack of proven therapies for this condition.

TRIAL REGISTRATION

This trial was funded by the Canadian Institutes of Health Research (grant number:222493) and is registered at ClinicalTrials.gov (NCT01353339).