Study of Cardiovascular Outcomes in Renal Transplantation: A Prospective, Multicenter Study to Determine the Incidence of Cardiovascular Events in Renal Transplant Recipients in Ontario, Canada

Background:

Renal transplant recipients (RTRs) are at significantly higher risk for morbidity and mortality compared with the general population, largely attributed to cardiovascular disease (CVD). Previous estimates of CVD events have come from health care databases and retrospective studies.

Objective:

The objective of this study was to prospectively determine the prevalence of risk factors and incidence of CVD events in a Canadian cohort of RTRs.

Design:

Study of Cardiovascular Outcomes in Renal Transplantation (SCORe) was a prospective, longitudinal, multicenter observational study.

Setting:

Adult RTRs were recruited from 6 participating transplant sites in Ontario, Canada.

Patients:

Eligible patients were those receiving a living or deceased donor renal transplant. Patients who received simultaneous transplant of any other organ were excluded.

Measurements:

Primary outcomes included myocardial infarction (MI) defined by American College of Cardiology (ACC-MI) criteria, and major adverse cardiac events (MACE), defined as cardiovascular (CV) death, ACC-MI, coronary revascularization, and nonhemorrhagic stroke. CV events were adjudicated by a single, independent cardiologist.

Methods:

CV and transplant-specific risk factors that predict MACE and ACC-MI were identified by stepwise regression analysis using the Cox proportional hazards model.

Results:

A total of 1303 patients enrolled across 6 transplant centers were followed for 4.5 ± 1.6 years (mean ± SD). Incidence of MACE was 7.0%, with significant independent predictors/risk factors including age, diabetes, coronary revascularization, nonhemorrhagic stroke, and renal replacement therapy (RRT). ACC-MI incidence was 4.0%, with significant independent predictors/risk factors including age, coronary revascularization, and duration of RRT in excess of the median value (2.91 years).

Limitations:

Patients were recruited from a single province, so may not reflect the experience of RTRs in other areas of Canada.

Conclusions:

Using a prospective design and rigorous methodology, this study found that the incidence of CV events after renal transplantation was elevated relative to the general Canadian population and was comparable with that reported in patient registries, thus helping validate the utility of retrospective analysis in this field. SCORe highlights the importance of monitoring RTRs for traditional cardiac and transplant-specific CV risk factors to help prevent CV morbidity and mortality. Further research is needed to investigate a broader range of potential risk factors and their combined effects on incident CV events.

A national survey of screening and management of hypogammaglobulinemia in Canadian transplantation centers

BACKGROUND

Infection remains one of the most common transplant-related causes of death in patients undergoing transplantation. Secondary hypogammaglobulinemia (HGG) as a component of immune suppression and deficiency is associated with both solid organ transplantation (SOT) and hematopoietic cell transplantation (HCT). Available data and clinical experience for the supplementation of immunoglobulin (Ig) in these patients is conflicting, and differing clinical opinion accounts for non-uniform practice in the use of Ig treatment. We aimed to survey lead transplant practitioners for current practice around polyvalent Ig use in post-transplant recipients across Canada.

METHODS

We performed a survey study using short questionnaires to estimate rate of screening of HGG, use of polyvalent Ig, and physician's opinion on Ig treatment and infection prevention. Directors of 24 SOT and 23 HCT centers across Canada were invited to participate in the survey via an electronic mail.

RESULTS

Overall response rate was 63.8%. Twenty percent of SOT programs routinely measured Ig levels pre-transplant compared to 33% of allogeneic (allo-) and 21% of autologous (auto-) HCT programs. Post-transplant Ig levels were measured in 13%, 75%, and 29% in SOT, allo-HCT, and auto-HCT, respectively. The SOT and auto-HCT groups indicated that they do not prescribe Ig therapy (100% and 86%), contrary to the allo-HCT group (42%). Of the respondents in the SOT, allo-HCT, and auto-HCT groups, 60%, 67%, and 36%, respectively, thought infections could be prevented with intravenous immunoglobulins (IVIg). A majority of respondents indicated they would be interested in participating in a randomized controlled trial evaluating the use of IVIg in the SOT and in both HCT groups (100%, 83%, and 57%, respectively).

CONCLUSIONS

Our study shows significant variation in practice between SOT and HCT centers with respect to screening and management of HGG. There is willingness to participate in a randomized controlled trial to address whether Ig treatment reduces infection in post-transplant recipients.

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.

Derivation of a Predictive Model for Graft Loss Following Acute Kidney Injury in Kidney Transplant Recipients

Background:

Acute kidney injury (AKI) is common in the kidney transplant population.

Objective:

To derive a multivariable survival model that predicts time to graft loss following AKI.

Design:

Retrospective cohort study using health care administrative and laboratory databases.

Setting:

Southwestern Ontario (1999-2013) and Ottawa, Ontario, Canada (1996-2013).

Patients:

We included first-time kidney only transplant recipients who had a hospitalization with AKI 6 months or greater following transplant.

Measurements:

AKI was defined using the Acute Kidney Injury Network criteria (stage 1 or greater). The first episode of AKI was included in the analysis. Graft loss was defined by return to dialysis or repeat kidney transplant.

Methods:

We performed a competing risk survival regression analysis using the Fine and Gray method and modified the model into a simple point system. Graft loss with death as a competing event was the primary outcome of interest.

Results:

A total of 315 kidney transplant recipients who had a hospitalization with AKI 6 months or greater following transplant were included. The median (interquartile range) follow-up time was 6.7 (3.3-10.3) years. Graft loss occurred in 27.6% of the cohort. The final model included 6 variables associated with an increased risk of graft loss: younger age, increased severity of AKI, failure to recover from AKI, lower baseline estimated glomerular filtration rate, increased time from kidney transplant to AKI admission, and receipt of a kidney from a deceased donor. The risk score had a concordance probability of 0.75 (95% confidence interval [CI], 0.69-0.82). The predicted 5-year risk of graft loss fell within the 95% CI of the observed risk more than 95% of the time.

Limitations:

The CIs of the estimates were wide, and model overfitting is possible due to the limited sample size; the risk score requires validation to determine its clinical utility.

Conclusions:

Our prognostic risk score uses commonly available information to predict the risk of graft loss in kidney transplant patients hospitalized with AKI. If validated, this predictive model will allow clinicians to identify high-risk patients who may benefit from closer follow-up or targeted enrollment in future intervention trials designed to improve outcomes.

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients

BACKGROUND

Agreement between spot and 24-hour urine protein measurements is poor in kidney transplant recipients. We investigated whether using formulae to estimate creatinine excretion rate (eCER), rather than assuming a standard creatinine excretion rate, would improve the estimation of proteinuria from spot urine samples in kidney transplant recipients.

METHODS

We measured 24 hour urine protein and albumin and spot albumin:creatinine (ACR) and spot protein:creatinine (PCR) in 181 Kidney transplant recipients." We utilized 6 different published formulae (Fotheringham, CKD-EPI, Cockcroft-Gault, Walser, Goldwasser and Rule) to estimate eCER and from it calculated estimated albumin and protein excretion rate (eAER and ePER). Bias, precision and accuracy (within 15%, 30% and 50%) of ACR, PCR, eAER, ePER were compared to 24-hour urine protein and albumin.

RESULTS

ACR and PCR significantly underestimated 24-hour albumin and protein excretion (ACR Bias (IQR), -5.9 mg/day; p< 0.01; PCR Bias, (IQR), -35.2 mg/day; p<0.01). None of the formulae used to calculate eAER or ePER had a bias that was significantly different from the 24-hour collection (eAER and ePER bias: Fotheringham -0.3 and 7.2, CKD-EPI 0.3 and 13.5, Cockcroft-Gault -3.2 and -13.9, Walser -1.7 and 3.1, Goldwasser -1.3 and -0.5, Rule -0.6 and 4.2 mg/day respectively. The accuracy for ACR and PCR were lower (within 30% being 38% and 43% respectively) than the corresponding values estimated by utilizing eCER (for eAER 46% to 49% and ePER 46-54%).

CONCLUSION

Utilizing estimated creatinine excretion to calculate eAER and ePER improves the estimation of 24-hour albuminuria/proteinuria with spot urine samples in kidney transplant recipients.

Antitumor activity of nivolumab on hemodialysis after renal allograft rejection

BACKGROUND

Nivolumab (Opdivo™) is a novel IgG4 subclass programmed death-1 (PD-1) inhibiting antibody that has demonstrated breakthrough-designation anti-tumor activity. To date, clinical trials of nivolumab and other checkpoint inhibitors have generally excluded patients with solid organ transplantation and patients with concurrent immunosuppression. However, organ transplant recipients are at high-risk of development of malignancy as a result of suppressed immune surveillance of cancer.

CASE PRESENTATION

We illustrate the outcomes of a 63 year-old type I diabetic female patient who developed pulmonary metastatic, BRAF wild-type cutaneous melanoma 10 years after renal transplantation. After downward titration of the patient's immunosuppressive medications and extensive multidisciplinary review, she was treated with nivolumab in the first-line setting. Within 1 week of administration, the patient experienced acute renal allograft rejection, renal failure and concurrent diabetic ketoacidosis due to steroid therapy. Allograft function did not return, but patient made a full clinical recovery after being placed on hemodialysis. Subsequently, the patient had clinical disease progression off therapy and required re-challenge with nivolumab on hemodialysis, resulting in ongoing clinical and radiographic response.

CONCLUSIONS

This case illustrates multiple practical challenges and dangers of administering anti-PD1 immune checkpoint inhibitors to patients with solid-organ transplantation including need for titration of immunosuppressive medications, risks of allograft rejection, and treatment during hemodialysis.

Registration for deceased organ and tissue donation among Ontario immigrants: a population-based cross-sectional study

BACKGROUND

Canada has low rates of deceased organ and tissue donation. Immigrants to Canada may differ in their registered support for deceased organ donation based on their country of origin.

METHODS

We used linked administrative databases in Ontario (about 11 million residents aged ≥ 16 yr) to study the proportion of immigrants and long-term residents registered for deceased organ and tissue donation as of October 2013. We used modified Poisson regression to identify and quantify predictors of donor registration.

RESULTS

Compared with long-term residents (n = 9 244 570), immigrants (n = 1 947 646) were much less likely to register for deceased organ and tissue donation (11.9% v. 26.5%). Immigrants from the United States, Australia and New Zealand had the highest registration rate (40.0%), whereas immigrants with the lowest registration rates were from Eastern Europe and Central Asia (9.4%), East Asia and Pacific (8.4%) and sub-Saharan Africa (7.9%). The largest numbers of unregistered immigrants were from India (n = 202 548), China (n = 186 678) and the Philippines (n = 125 686). Characteristics among the immigrant population associated with a higher likelihood of registration included economic immigrant status, living in a rural area (population < 10 000), living in an area with a lower ethnic concentration, less material deprivation, a higher education, ability to speak English and French, and more years residing in Canada.

INTERPRETATION

Immigrants in Ontario were less likely to register for deceased organ and tissue donation than long-term residents. There is a need to better understand reasons for lower registration rates among Canadian immigrants and to create culture-sensitive materials to build support for deceased organ and tissue donation.

Association of Blood Donor Age and Sex With Recipient Survival After Red Blood Cell Transfusion

IMPORTANCE

While red blood cells (RBCs) are administered to improve oxygen delivery and patient outcomes, they also have been associated with potential harm. Unlike solid organ transplantation, the clinical consequences of donor characteristics on recipients have not been evaluated in transfusion medicine.

OBJECTIVE

To analyze the association of RBC donor age and sex with the survival of transfusion recipients.

DESIGN, SETTING, AND PARTICIPANTS

We established a longitudinal cohort by linking data from a blood collection agency with clinical and administrative data at 4 academic hospitals.

MAIN OUTCOMES AND MEASURES

Cox proportional hazards regression models were fitted to evaluate the risk of donor age and sex on transfusion recipient survival.

RESULTS

Between October 25, 2006, and December 31, 2013, a total of 30 503 RBC transfusion recipients received 187 960 RBC transfusions from 80 755 unique blood donors. For recipients receiving an RBC unit from younger donors, the risk of death was increased compared with recipients receiving an RBC unit from a donor 40 to 49.9 years old (adjusted hazard ratio, 1.08; 95% CI, 1.06-1.10; P < .001 for donor age range 17-19.9 years and 1.06; 95% CI, 1.04-1.09; P < .001 for donor age range 20-29.9 years). Receiving an RBC transfusion from a female donor was associated with an 8% statistically significant increased risk of death compared with receiving an RBC transfusion from a male donor (adjusted hazard ratio, 1.08; 95% CI, 1.06-1.09; P < .001).

CONCLUSIONS AND RELEVANCE

Red blood cell transfusions from younger donors and from female donors were statistically significantly associated with increased mortality. These findings suggest that donor characteristics may affect RBC transfusion outcomes.

Validation of administrative database codes for acute kidney injury in kidney transplant recipients

Background

Validation studies of acute kidney injury (AKI) diagnostic codes performed in the general population have shown poor sensitivity, but the accuracy of such codes in the kidney transplant population remains unknown.

Objective

The objective of this study is to determine the accuracy of AKI diagnostic codes in kidney transplant recipients. We hypothesized that the sensitivity of diagnostic codes would be significantly greater in the kidney transplant population since these patients are closely followed by nephrologists and are more likely to have serum creatinine measured.

Design

The design is a population-based retrospective cohort study using healthcare administrative and laboratory databases.

Setting

The setting is in Southwestern Ontario and Ottawa, Ontario, Canada, from 2003 to 2012.

Patients

We included first-time kidney transplant recipients admitted to hospital for whom serum creatinine was measured in hospital and within 6 months prior (n = 524).

Methods

Patients meeting the Acute Kidney Injury Network (AKIN) classification serum creatinine change criteria were classified as having AKI. We determined the sensitivity, specificity, and negative and positive predictive values for the ICD-10-CA code for AKI when present as an admission diagnosis, most responsible diagnosis, or any diagnosis compared to a reference standard of AKI defined by the AKIN criteria (stage 1 or greater, stage 2 or greater, or stage 3).

Results

Forty-five percent of included kidney transplant patients had a diagnosis of AKI. The most sensitive coding algorithm (reference standard AKIN stage 2 or greater, ICD-10 code present as any diagnosis) had a sensitivity of 42.1 % (95 % CI 31.7, 53.3), a specificity of 90.6 % (95 % CI 87.6, 93.0), and a positive likelihood ratio of 4.5. The median (IQR) rise in serum creatinine from baseline in patients with and without AKI codes was 104 (57 to 158) μmol/L and 16 (−3 to 41) μmol/L, respectively (Mann-Whitney test, p < 0.0001).

Limitations

The low sensitivity of the AKI code may be due to an alternative diagnosis of acute rejection being assigned in certain cases. The cause of AKI could not be determined.

Conclusions

Similar to the general population, the ICD-10 N17x code misses many kidney transplant patients with AKI during their hospitalization. This makes the code unusable for studying the incidence and consequences of AKI in hospitalized kidney transplant patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s40697-016-0108-7) contains supplementary material, which is available to authorized users.

Protocol for updating a systematic review of randomised controlled trials on the prophylactic use of intravenous immunoglobulin for patients undergoing haematopoietic stem cell transplantation

INTRODUCTION

Haematopoietic stem cell transplantation (HSCT) is commonly employed in the management of haematological malignancies. This intervention results in an increased risk of infectious and immune-related complications. Prophylactic immunoglobulin therapy has been used to prevent post-HSCT complications, including infections, with varying efficacy. We sought to update the current evidence supporting the use of immunoglobulins in the modern HSCT era.

METHODS/ANALYSIS

Using a structured search strategy, we will perform a systematic review of the literature from MEDLINE, EMBASE and all EBM Reviews databases. We will include randomised clinical trials investigating clinical outcomes of prophylactic polyvalent immunoglobulin or cytomegalovirus (CMV)-specific immunoglobulin or plasma in patients undergoing HSCT. Clinical outcomes will include overall survival, transplant-related mortality, CMV infection, CMV disease, graft-versus-host disease, interstitial pneumonitis/fibrosis and hepatic veno-occlusive disease. Studies that only reported the results of biochemical tests will be excluded. Data will be extracted by two investigators independently. Study quality assessment will be evaluated using a validated five-point system as proposed by Jadad. Trial quality will be further assessed by identifying whether there was adequate allocation concealment. Where appropriate, a meta-analysis will be performed where relative risk will be used as the primary summary measure with 95% CIs. Pooled measures will be calculated for randomised clinical trials using a random-effects model. The Cochrane Q/χ(2) test and I(2) statistic will also be calculated to evaluate heterogeneity. We will also use a visual inspection of a funnel plot to assess potential publication bias.

DISCUSSION

This systematic review aims to provide current evidence to justify the use of immunoglobulin prophylaxis in HSCT recipients. We will discuss whether current HSCT guidelines are supported by the current evidence, and whether further trials are needed, given the changing landscape of patients undergoing HSCT and the immunoglobulin manufacturing process.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015016684.

Deceased Organ Donation Registration and Familial Consent among Chinese and South Asians in Ontario, Canada

Objective

For various reasons, people of Chinese (China, Hong Kong or Taiwan) and South Asian (Indian subcontinent) ancestry (the two largest ethnic minority groups in Ontario, Canada) may be less likely to register for deceased organ donation than the general public, and their families may be less likely to consent for deceased organ donation at the time of death.

Methods

We conducted two population-based studies: (1) a cross-sectional study of deceased organ donor registration as of May 2013, and (2) a cohort study of the steps in proceeding with deceased organ donation for patients who died in hospital from October 2008 to December 2012.

Results

A total of 49 938 of 559 714 Chinese individuals (8.9%) and 47 774 of 374 291 South Asians (12.8%) were registered for deceased organ donation, proportions lower than the general public (2 676 260 of 10 548 249 (25.4%). Among the 168 703 Ontarians who died in a hospital, the families of 33 of 81 Chinese (40.1%; 95% CI: 30.7%-51.6%) and 39 of 72 South Asian individuals (54.2%; 95% CI: 42.7-65.2%) consented for deceased organ donation, proportions lower than the general public (68.3%; 95% CI: 66.4%-70.0%).

Conclusions

In Ontario, Canada Chinese and South Asian individuals are less likely to register and their families are less likely to consent to deceased organ donation compared to the remaining general public. There is an opportunity to build support for organ and tissue donation in these two large ethnic communities in Canada.

Clinical effects of blood donor characteristics in transfusion recipients: protocol of a framework to study the blood donor-recipient continuum

INTRODUCTION

When used appropriately, transfusion of red blood cells (RBCs) is a necessary life-saving therapy. However, RBC transfusions have been associated with negative outcomes such as infection and organ damage. Seeking explanations for the beneficial and deleterious effects of RBC transfusions is necessary to ensure the safe and optimal use of this precious resource. This study will create a framework to analyse the influence of blood donor characteristics on recipient outcomes.

METHODS AND ANALYSIS

We will conduct a multisite, longitudinal cohort study using blood donor data routinely collected by Canadian Blood Services, and recipient data from health administrative databases. Our project will include a thorough validation of primary data, the linkage of various databases into one large longitudinal database, an in-depth epidemiological analysis and a careful interpretation and dissemination of the results to assist the decision-making process of clinicians, researchers and policymakers in transfusion medicine. Our primary donor characteristic will be age of blood donors and our secondary donor characteristics will be donor-recipient blood group compatibility and blood donor sex. Our primary recipient outcome will be a statistically appropriate survival analysis post-RBC transfusion up to a maximum of 8 years. Our secondary recipient outcomes will include 1-year, 2-year and 5-year mortality; hospital and intensive care unit length of stay; rehospitalisation; new cancer and cancer recurrence rate; infection rate; new occurrence of myocardial infarctions and need for haemodialysis.

ETHICS AND DISSEMINATION

Our results will help determine whether we need to tailor transfusion based on donor characteristics, and perhaps this will improve patient outcome. Our results will be customised to target the different stakeholders involved with blood transfusions and will include presentations, peer-reviewed publications and the use of the dissemination network of blood supply organisations. We obtained approval from the Research Ethics boards and privacy offices of all involved institutions.

Two-stage, in silico deconvolution of the lymphocyte compartment of the peripheral whole blood transcriptome in the context of acute kidney allograft rejection

Acute rejection is a major complication of solid organ transplantation that prevents the long-term assimilation of the allograft. Various populations of lymphocytes are principal mediators of this process, infiltrating graft tissues and driving cell-mediated cytotoxicity. Understanding the lymphocyte-specific biology associated with rejection is therefore critical. Measuring genome-wide changes in transcript abundance in peripheral whole blood cells can deliver a comprehensive view of the status of the immune system. The heterogeneous nature of the tissue significantly affects the sensitivity and interpretability of traditional analyses, however. Experimental separation of cell types is an obvious solution, but is often impractical and, more worrying, may affect expression, leading to spurious results. Statistical deconvolution of the cell type-specific signal is an attractive alternative, but existing approaches still present some challenges, particularly in a clinical research setting. Obtaining time-matched sample composition to biologically interesting, phenotypically homogeneous cell sub-populations is costly and adds significant complexity to study design. We used a two-stage, in silico deconvolution approach that first predicts sample composition to biologically meaningful and homogeneous leukocyte sub-populations, and then performs cell type-specific differential expression analysis in these same sub-populations, from peripheral whole blood expression data. We applied this approach to a peripheral whole blood expression study of kidney allograft rejection. The patterns of differential composition uncovered are consistent with previous studies carried out using flow cytometry and provide a relevant biological context when interpreting cell type-specific differential expression results. We identified cell type-specific differential expression in a variety of leukocyte sub-populations at the time of rejection. The tissue-specificity of these differentially expressed probe-set lists is consistent with the originating tissue and their functional enrichment consistent with allograft rejection. Finally, we demonstrate that the strategy described here can be used to derive useful hypotheses by validating a cell type-specific ratio in an independent cohort using the nanoString nCounter assay.

Economic consequences incurred by living kidney donors: a Canadian multi-center prospective study

Some living kidney donors incur economic consequences as a result of donation; however, these costs are poorly quantified. We developed a framework to comprehensively assess economic consequences from the donor perspective including out-of-pocket cost, lost wages and home productivity loss. We prospectively enrolled 100 living kidney donors from seven Canadian centers between 2004 and 2008 and collected and valued economic consequences ($CAD 2008) at 3 months and 1 year after donation. Almost all (96%) donors experienced economic consequences, with 94% reporting travel costs and 47% reporting lost pay. The average and median costs of lost pay were $2144 (SD 4167) and $0 (25th-75th percentile 0, 2794), respectively. For other expenses (travel, accommodation, medication and medical), mean and median costs were $1780 (SD 2504) and $821 (25th-75th percentile 242, 2271), respectively. From the donor perspective, mean cost was $3268 (SD 4704); one-third of donors incurred cost >$3000, and 15% >$8000. The majority of donors (83%) reported inability to perform usual household activities for an average duration of 33 days; 8% reported out-of-pocket costs for assistance with these activities. The economic impact of living kidney donation for some individuals is large. We advocate for programs to reimburse living donors for their legitimate costs.

Effect of blood donor characteristics on transfusion outcomes: a protocol for systematic review and meta-analysis

BACKGROUND

Optimal selection of blood donors is of paramount importance in ensuring the safety of blood products. The current selection process is concerned principally with the safety of the blood donor and the safety of the patient that receives the blood. Recent evidence suggests that the characteristics of the donor may affect transfusion outcomes for the recipient.

METHODS

We will conduct a systematic review of the association between major blood donor characteristics and red blood cell (RBC) transfusion outcomes. The primary objective is to assess the association of blood donor characteristics and the risk of adverse short-term and long-term clinical outcomes after RBC transfusion. We will search MEDLINE, EMBASE, Cochrane Central databases, as well as perform manual searches of top transfusion medical journals for prospective and retrospective studies. Study characteristics will be reported and the methodological quality of studies will be assessed. When appropriate, we will provide pooled odds ratio with 95% confidence intervals of the effect estimates, study clinical heterogeneity using pre-defined sensitivity and subgroup analyses, and study statistical heterogeneity using the I2 test.

DISCUSSION

The results of this systematic review will provide an evidence base regarding the potential clinical effects of donor characteristics on transfusion recipients to better guide policy and clinical practice. The evidence gathered from this review will also identify strengths and weaknesses of published studies regarding donor characteristics and transfusion outcomes and will identify knowledge gaps to inform future research in this field of transfusion medicine.

TRIAL REGISTRATION

PROSPERO Registration Number: CRD42013006726.

Checking whether there is an increased risk of post-transplant lymphoproliferative disorder and other cancers with specific modern immunosuppression regimens in renal transplantation: protocol for a network meta-analysis of randomized and observational studies

BACKGROUND

Patients undergoing renal transplant procedures require multi-agent immunosuppressive regimens both short term (induction phase) and long term (maintenance phase) to minimize the risk of organ rejection. There are several drug classes and agents for immunosuppression. Use of these agents may increase the risk of different harms including not only infections, but also malignancies including post-transplant lymphoproliferative disorder. There is a need to identify which regimens minimize the risk of such outcomes. The objective of this systematic review and network meta-analysis of randomized and observational studies is to explore whether certain modern regimens of immunosuppression used to prevent organ rejection in renal transplant patients are associated with an increased risk of post-transplant lymphoproliferative disorder and other malignancies.

METHODS/DESIGN

'Modern' regimens were defined to be those evaluated in controlled studies beginning in 1990 or later. An electronic literature search of Medline, Embase and the Cochrane Central Register of Controlled Trials has been designed by an experienced information specialist and peer reviewed by a second information specialist. Study selection and data collection will be performed by two reviewers. The outcomes of interest will include post-transplant lymphoproliferative disorder and other incident forms of malignancy occurring in adult renal transplant patients. Network meta-analyses of data from randomized and observational studies will be performed where judged appropriate based on a review of the clinical and methodological features of included studies. A sequential approach to meta-analysis will be used to combine data from different designs.

DISCUSSION

Our systematic review will include both single-agent and multi-agent modern pharmacotherapy regimens in patients undergoing renal transplantation. It will synthesize malignancy outcomes. Our work will also add to the development of methods for network meta-analysis across study designs to assess treatment safety.

TRIAL REGISTRATION

PROSPERO Registration Number: CRD42013006951.

Longitudinal Analysis of Whole Blood Transcriptomes to Explore Molecular Signatures Associated with Acute Renal Allograft Rejection

In this study, we explored a time course of peripheral whole blood transcriptomes from kidney transplantation patients who either experienced an acute rejection episode or did not in order to better delineate the immunological and biological processes measureable in blood leukocytes that are associated with acute renal allograft rejection. Using microarrays, we generated gene expression data from 24 acute rejectors and 24 nonrejectors. We filtered the data to obtain the most unambiguous and robustly expressing probe sets and selected a subset of patients with the clearest phenotype. We then performed a data-driven exploratory analysis using data reduction and differential gene expression analysis tools in order to reveal gene expression signatures associated with acute allograft rejection. Using a template-matching algorithm, we then expanded our analysis to include time course data, identifying genes whose expression is modulated leading up to acute rejection. We have identified molecular phenotypes associated with acute renal allograft rejection, including a significantly upregulated signature of neutrophil activation and accumulation following transplant surgery that is common to both acute rejectors and nonrejectors. Our analysis shows that this expression signature appears to stabilize over time in nonrejectors but persists in patients who go on to reject the transplanted organ. In addition, we describe an expression signature characteristic of lymphocyte activity and proliferation. This lymphocyte signature is significantly downregulated in both acute rejectors and nonrejectors following surgery; however, patients who go on to reject the organ show a persistent downregulation of this signature relative to the neutrophil signature.

Longitudinal analysis of whole blood transcriptomes to explore molecular signatures associated with acute renal allograft rejection

In this study, we explored a time course of peripheral whole blood transcriptomes from kidney transplantation patients who either experienced an acute rejection episode or did not in order to better delineate the immunological and biological processes measureable in blood leukocytes that are associated with acute renal allograft rejection. Using microarrays, we generated gene expression data from 24 acute rejectors and 24 nonrejectors. We filtered the data to obtain the most unambiguous and robustly expressing probe sets and selected a subset of patients with the clearest phenotype. We then performed a data-driven exploratory analysis using data reduction and differential gene expression analysis tools in order to reveal gene expression signatures associated with acute allograft rejection. Using a template-matching algorithm, we then expanded our analysis to include time course data, identifying genes whose expression is modulated leading up to acute rejection. We have identified molecular phenotypes associated with acute renal allograft rejection, including a significantly upregulated signature of neutrophil activation and accumulation following transplant surgery that is common to both acute rejectors and nonrejectors. Our analysis shows that this expression signature appears to stabilize over time in nonrejectors but persists in patients who go on to reject the transplanted organ. In addition, we describe an expression signature characteristic of lymphocyte activity and proliferation. This lymphocyte signature is significantly downregulated in both acute rejectors and nonrejectors following surgery; however, patients who go on to reject the organ show a persistent downregulation of this signature relative to the neutrophil signature.