Ancillary testing for diagnosis of brain death: a protocol for a systematic review and meta-analysis

BACKGROUND

The essential clinical diagnostic components of brain death must include evidence for an established etiology capable of causing brain death, two independent clinical confirmations of the absence of all brainstem reflexes and an apnea test, and exclude confounders that can mimic brain death. Numerous confounders can render the clinical neurological determination of death (NDD) virtually impossible. As such, clinicians must rely on additional ancillary testing.

METHODS/DESIGN

We will conduct a systematic review and a meta-analysis of ancillary testing for the neurological determination of death. The primary objective of this systematic review is to evaluate the accuracy of these ancillary tests compared to the three accepted reference standards: (1) clinical diagnosis, (2) four-vessel angiography and (3) radionuclide imaging. This objective will be investigated using two different populations with different baseline risks of brain death: comatose patients and patients with a neurological determination of death. We will search MEDLINE, EMBASE and the Cochrane Central databases for retrospective and prospective diagnostic test studies and interventional studies. We will report study characteristics and assess methodological quality using QUADAS-2, which is used to assess the quality of diagnostic tests. If pooling is appropriate, we will compute parameter estimates using a bivariate model to produce summary receiver operating curves, summary operating points (pooled sensitivity and specificity), and 95% confidence regions around the summary operating point. Clinical and methodological subgroup and sensitivity analyses will be performed to explore heterogeneity.

DISCUSSION

The results of this project will provide a critical evidence base for the neurological determination of death. The results will help clinicians to select ancillary tests based on the best available evidence. Our systematic review will also identify the strengths and weaknesses in the current evidence for the use of ancillary tests in diagnosing brain death. It will serve as a foundation for further research and the development of prospective studies on currently used or novel techniques for NDD.

PROTOCOL REGISTRATION

PROSPERO Registration Number: CRD42013005907.

Survival trends in ESRD patients compared with the general population in the United States

BACKGROUND

Health care resources expended on patients with end-stage renal disease (ESRD) have increased extensively, with uncertain changes in outcomes. In this study, we examined survival trends in the United States in patients with ESRD receiving renal replacement therapy with long-term dialysis or transplantation relative to the general population.

STUDY DESIGN

Secondary analysis of records from the US Renal Data System.

SETTING & PARTICIPANTS

American adults receiving renal replacement therapy in 1977, 1987, 1997, and 2007.

PREDICTOR

Year.

OUTCOME

1-year survival.

MEASUREMENTS

Abridged period life tables were created for each cross-sectional patient group and were compared with general US population life tables to measure relative survival, calculated as differences in average survival between the general US and the ESRD populations.

RESULTS

From 1977 to 2007, ESRD patient groups became significantly older (mean age increased from 47 to 58 years) and sicker (ESRD due to diabetes increased from 9.1% to 38.2%; patients with a high death risk increased from 36.8% to 50.7%). Unadjusted age-specific survival improved (for 50-year-olds, average life expectancy increased 8% from 7.3 years in 1977 to 7.9 years in 2007), but age-specific survival increased more extensively in the general US population (from 27.5 years in 1977 to 30.9 years in 2007; 12% improvement). Accounting for this, age-specific relative survival in patients with ESRD decreased (for 50-year-olds, 20.2 life-years lost in 1977 vs 23.0 life-years lost in 2007).

LIMITATIONS

Our analysis controlled for neither patient comorbid conditions nor initial glomerular filtration rate at the start of renal replacement therapy.

CONCLUSIONS

Over the past 4 decades, age-specific survival in patients with ESRD has improved, but has not kept pace with that of the general US population. To be complete, future survival studies in patients with ESRD should focus on both temporal changes in survival within this group and changes relative to the general population.

Validity of physician billing claims to identify deceased organ donors in large healthcare databases

Objective

We evaluated the validity of physician billing claims to identify deceased organ donors in large provincial healthcare databases.

Methods

We conducted a population-based retrospective validation study of all deceased donors in Ontario, Canada from 2006 to 2011 (n = 988). We included all registered deaths during the same period (n = 458,074). Our main outcome measures included sensitivity, specificity, positive predictive value, and negative predictive value of various algorithms consisting of physician billing claims to identify deceased organ donors and organ-specific donors compared to a reference standard of medical chart abstraction.

Results

The best performing algorithm consisted of any one of 10 different physician billing claims. This algorithm had a sensitivity of 75.4% (95% CI: 72.6% to 78.0%) and a positive predictive value of 77.4% (95% CI: 74.7% to 80.0%) for the identification of deceased organ donors. As expected, specificity and negative predictive value were near 100%. The number of organ donors identified by the algorithm each year was similar to the expected value, and this included the pre-validation period (1991 to 2005). Algorithms to identify organ–specific donors performed poorly (e.g. sensitivity ranged from 0% for small intestine to 67% for heart; positive predictive values ranged from 0% for small intestine to 37% for heart).

Interpretation

Primary data abstraction to identify deceased organ donors should be used whenever possible, particularly for the detection of organ-specific donations. The limitations of physician billing claims should be considered whenever they are used.

A simple method to estimate renal volume from computed tomography

INTRODUCTION

Renal parenchymal volume can be used clinically to estimate differential renal function. Unfortunately, conventional methods to determine renal volume from computed tomography (CT) are time-consuming or difficult due to software limitations. We evaluated the accuracy of simple renal measurements to estimate renal volume as compared with estimates made using specialized CT volumetric software.

METHODS

We reviewed 28 patients with contrast-enhanced abdominal CT. Using a standardized technique, one urologist and one urology resident independently measured renal length, lateral diameter and anterior-posterior diameter. Using the ellipsoid method, the products of the linear measurements were compared to 3D volume measurements made by a radiologist using specialized volumetric software.

RESULTS

LINEAR KIDNEY MEASUREMENTS WERE HIGHLY CONSISTENT BETWEEN THE UROLOGIST AND THE UROLOGY RESIDENT (INTRACLASS CORRELATION COEFFICIENTS: 0.97 for length, 0.96 for lateral diameter, and 0.90 for anterior-posterior diameter). Average renal volume was 170 (SD: 36) cm(3) using the ellipsoid method compared with 186 (SD 37) cm(3) using volumetric software, for a mean absolute bias of -15.2 (SD 15.0) cm(3) and a relative volume bias of -8.2% (p < 0.001). Thirty-one of 56 (55.3%) estimated volumes were within 10% of the 3D measured volume and 54 of 56 (96.4%) were within 30%.

CONCLUSION

Renal volume can be easily approximated from contrast-enhanced CT scans using the ellipsoid method. These findings may obviate the need for 3D volumetric software analysis in certain cases. Prospective validation is warranted.

Temporary hemodialysis catheter placement by nephrology fellows: implications for nephrology training

The insertion of temporary hemodialysis catheters is considered to be a core competency of nephrology fellowship training. Little is known about the adequacy of training for this procedure and the extent to which evidence-based techniques to reduce complications have been adopted. We conducted a web-based survey of Canadian nephrology trainees regarding the insertion of temporary hemodialysis catheters. Responses were received from 45 of 68 (66%) eligible trainees. The median number of temporary hemodialysis catheters inserted during the prior 6 months of training was 5 (IQR, 2-11), with 9 (20%) trainees reporting they had inserted none. More than one-third of respondents indicated that they were not adequately trained to competently insert temporary hemodialysis catheters at both the femoral and internal jugular sites. These findings are relevant to a discussion of the current adequacy of procedural skills training during nephrology fellowship. With respect to temporary hemodialysis catheter placement, there is an opportunity for increased use of simulation-based teaching by training programs. Certain infection control techniques and use of real-time ultrasound should be more widely adopted. Consideration should be given to the establishment of minimum procedural training requirements at the level of both individual training programs and nationwide certification authorities.

Poor seroprotection but allosensitization after adjuvanted pandemic influenza H1N1 vaccine in kidney transplant recipients

BACKGROUND

Seasonal and pandemic influenza virus infections in renal transplant patients are associated with poor outcomes. During the pandemic of 2009-2010, the AS03-adjuvanted monovalent H1N1 influenza vaccine was recommended for transplant recipients, although its immunogenicity in this population was unknown. We sought to determine the safety and immunogenicity of an adjuvant-containing vaccine against pandemic influenza A H1N1 2009 (pH1N1) administered to kidney transplant recipients.

METHODS

We prospectively enrolled 124 adult kidney transplant recipients in the fall of 2009 at two transplant centers. Cohort 1 (n = 42) was assessed before and after pH1N1 immunization, while Cohort 2 (n = 82) was only assessed post immunization. Humoral response was measured by the hemagglutination inhibition assay. Vaccine safety was assessed by adverse event reporting, graft function, and human leukocyte antigen (HLA) alloantibody measurements.

RESULTS

Cohort 1 had a low rate of baseline seroprotection to pH1N1 (7%) and a low rate of seroprotection after immunization (31%). No patient <6 months post transplant (n = 5) achieved seroprotection. Seroprotection rate was greater in patients receiving double as compared with triple immunosuppression (80% vs. 24%, P = 0.01). In Cohort 2, post-immunization seroprotection was 35%. In both cohorts, no confirmed cases of pH1N1 infection occurred. No difference was seen in estimated glomerular filtration rate before (54.3 mL/min/1.73 m(2) ) and after (53.8 mL/min/1.73 m(2) ) immunization, and no acute rejections had occurred after immunization at last follow-up. In Cohort 1, 11.9% of patients developed new anti-HLA antibodies.

CONCLUSION

An adjuvant-containing vaccine to pH1N1 provided poor seroprotection in renal transplant recipients. Receiving triple immunosuppression was associated with a poor seroresponse. Vaccination appeared safe, but some patients developed new anti-HLA antibodies post vaccination. Alternative strategies to improve vaccine responses are necessary.

Increased urinary angiotensin-converting enzyme 2 in renal transplant patients with diabetes

Angiotensin-converting enzyme 2 (ACE2) is expressed in the kidney and may be a renoprotective enzyme, since it converts angiotensin (Ang) II to Ang-(1-7). ACE2 has been detected in urine from patients with chronic kidney disease. We measured urinary ACE2 activity and protein levels in renal transplant patients (age 54 yrs, 65% male, 38% diabetes, n = 100) and healthy controls (age 45 yrs, 26% male, n = 50), and determined factors associated with elevated urinary ACE2 in the patients. Urine from transplant subjects was also assayed for ACE mRNA and protein. No subjects were taking inhibitors of the renin-angiotensin system. Urinary ACE2 levels were significantly higher in transplant patients compared to controls (p = 0.003 for ACE2 activity, and p≤0.001 for ACE2 protein by ELISA or western analysis). Transplant patients with diabetes mellitus had significantly increased urinary ACE2 activity and protein levels compared to non-diabetics (p<0.001), while ACE2 mRNA levels did not differ. Urinary ACE activity and protein were significantly increased in diabetic transplant subjects, while ACE mRNA levels did not differ from non-diabetic subjects. After adjusting for confounding variables, diabetes was significantly associated with urinary ACE2 activity (p = 0.003) and protein levels (p<0.001), while female gender was associated with urinary mRNA levels for both ACE2 and ACE. These data indicate that urinary ACE2 is increased in renal transplant recipients with diabetes, possibly due to increased shedding from tubular cells. Urinary ACE2 could be a marker of renal renin-angiotensin system activation in these patients.

Tinzaparin versus dalteparin for periprocedure prophylaxis of thromboembolic events in hemodialysis patients: a randomized trial

BACKGROUND

Low-molecular-weight heparin (LMWH) is cleared predominantly by the kidneys and hence there is uncertainty about the safety of its use in hemodialysis (HD) patients. Our primary objective was to compare whether tinzaparin and dalteparin differentially accumulate in HD patients.

STUDY DESIGN

Open-label randomized controlled trial.

SETTING & PARTICIPANTS

HD patients undergoing periprocedure bridging anticoagulation.

INTERVENTION

After warfarin therapy was discontinued, participants were randomly assigned to either 3 daily doses of tinzaparin (175 IU/kg) or dalteparin (200 IU/kg), with 2 intervening HD treatments between the first dose of study drug and their procedure.

OUTCOMES

The primary outcome was predialysis anti-Xa levels 20 to 24 hours after the third LMWH dose (therapeutic target, <0.2 IU/mL). Secondary outcomes included thromboembolic events and major bleeding.

RESULTS

Of 29 eligible and consenting patients, 17 patients received tinzaparin and 12 patients received dalteparin. Mean predialysis anti-Xa level 20-24 hours after the third LMWH dose was 0.37 ± 0.23 (SD) IU/mL for tinzaparin and 0.62 ± 0.41 IU/mL for dalteparin (P = 0.1), indicating clinically important accumulation for both drugs. No invasive procedures were canceled due to study drug accumulation. 4 patients experienced serious adverse events (1 major bleed after traumatic arteriovenous fistula puncture in the tinzaparin arm, 2 non-ST-elevation myocardial infarctions [1 in each group], and 1 upper-extremity deep venous thrombosis [dalteparin group]).

LIMITATIONS

Small sample size.

CONCLUSIONS

Dalteparin and tinzaparin significantly accumulate in HD patients at therapeutic doses. "Bridging therapy" with LMWHs at therapeutic doses in HD patients who require temporary interruption of warfarin therapy has the potential for complications and is of uncertain benefit. Other anticoagulation strategies, including no bridging therapy or intravenous heparin, need comparative evaluation in this unique patient population.

Cardiovascular disease in kidney donors: matched cohort study

OBJECTIVE

To determine whether people who donate a kidney have an increased risk of cardiovascular disease.

DESIGN

Retrospective population based matched cohort study.

PARTICIPANTS

All people who were carefully selected to become a living kidney donor in the province of Ontario, Canada, between 1992 and 2009. The information in donor charts was manually reviewed and linked to provincial healthcare databases. Matched non-donors were selected from the healthiest segment of the general population. A total of 2028 donors and 20,280 matched non-donors were followed for a median of 6.5 years (maximum 17.7 years). Median age was 43 at the time of donation (interquartile range 34-50) and 50 at the time of follow-up (42-58).

MAIN OUTCOME MEASURES

The primary outcome was a composite of time to death or first major cardiovascular event. The secondary outcome was time to first major cardiovascular event censored for death.

RESULTS

The risk of the primary outcome of death and major cardiovascular events was lower in donors than in non-donors (2.8 v 4.1 events per 1000 person years; hazard ratio 0.66, 95% confidence interval 0.48 to 0.90). The risk of major cardiovascular events censored for death was no different in donors than in non-donors (1.7 v 2.0 events per 1000 person years; 0.85, 0.57 to 1.27). Results were similar in all sensitivity analyses. Older age and lower income were associated with a higher risk of death and major cardiovascular events in both donors and non-donors when each group was analysed separately.

CONCLUSIONS

The risk of major cardiovascular events in donors is no higher in the first decade after kidney donation compared with a similarly healthy segment of the general population. While we will continue to follow people in this study, these interim results add to the evidence base supporting the safety of the practice among carefully selected donors.

Should the arteriovenous fistula be created before starting dialysis?: a decision analytic approach

Background

An arteriovenous fistula (AVF) is considered the vascular access of choice, but uncertainty exists about the optimal time for its creation in pre-dialysis patients. The aim of this study was to determine the optimal vascular access referral strategy for stage 4 (glomerular filtration rate <30 ml/min/1.73 m²) chronic kidney disease patients using a decision analytic framework.

Methods

A Markov model was created to compare two strategies: refer all stage 4 chronic kidney disease patients for an AVF versus wait until the patient starts dialysis. Data from published observational studies were used to estimate the probabilities used in the model. A Markov cohort analysis was used to determine the optimal strategy with life expectancy and quality adjusted life expectancy as the outcomes. Sensitivity analyses, including a probabilistic sensitivity analysis, were performed using Monte Carlo simulation.

Results

The wait strategy results in a higher life expectancy (66.6 versus 65.9 months) and quality adjusted life expectancy (38.9 versus 38.5 quality adjusted life months) than immediate AVF creation. It was robust across all the parameters except at higher rates of progression and lower rates of ischemic steal syndrome.

Conclusions

Early creation of an AVF, as recommended by most guidelines, may not be the preferred strategy in all pre-dialysis patients. Further research on cost implications and patient preferences for treatment options needs to be done before recommending early AVF creation.

Systematic review: kidney transplantation compared with dialysis in clinically relevant outcomes

Individual studies indicate that kidney transplantation is associated with lower mortality and improved quality of life compared with chronic dialysis treatment. We did a systematic review to summarize the benefits of transplantation, aiming to identify characteristics associated with especially large or small relative benefit. Results were not pooled because of expected diversity inherent to observational studies. Risk of bias was assessed using the Downs and Black checklist and items related to time-to-event analysis techniques. MEDLINE and EMBASE were searched up to February 2010. Cohort studies comparing adult chronic dialysis patients with kidney transplantation recipients for clinical outcomes were selected. We identified 110 eligible studies with a total of 1 922 300 participants. Most studies found significantly lower mortality associated with transplantation, and the relative magnitude of the benefit seemed to increase over time (p < 0.001). Most studies also found that the risk of cardiovascular events was significantly reduced among transplant recipients. Quality of life was significantly and substantially better among transplant recipients. Despite increases in the age and comorbidity of contemporary transplant recipients, the relative benefits of transplantation seem to be increasing over time. These findings validate current attempts to increase the number of people worldwide that benefit from kidney transplantation.

Systematic review: kidney transplantation compared with dialysis in clinically relevant outcomes

Individual studies indicate that kidney transplantation is associated with lower mortality and improved quality of life compared with chronic dialysis treatment. We did a systematic review to summarize the benefits of transplantation, aiming to identify characteristics associated with especially large or small relative benefit. Results were not pooled because of expected diversity inherent to observational studies. Risk of bias was assessed using the Downs and Black checklist and items related to time-to-event analysis techniques. MEDLINE and EMBASE were searched up to February 2010. Cohort studies comparing adult chronic dialysis patients with kidney transplantation recipients for clinical outcomes were selected. We identified 110 eligible studies with a total of 1 922 300 participants. Most studies found significantly lower mortality associated with transplantation, and the relative magnitude of the benefit seemed to increase over time (p < 0.001). Most studies also found that the risk of cardiovascular events was significantly reduced among transplant recipients. Quality of life was significantly and substantially better among transplant recipients. Despite increases in the age and comorbidity of contemporary transplant recipients, the relative benefits of transplantation seem to be increasing over time. These findings validate current attempts to increase the number of people worldwide that benefit from kidney transplantation.

Organ donation after cardiac death: donor and recipient outcomes after the first three years of the Ontario experience

PURPOSE

The aim of this study was to explore donor and recipient outcomes from organ donation after cardiac death (DCD) in Ontario and to examine the impact of DCD on deceased donation rates in Ontario since its implementation.

METHODS

Donor data were obtained from the Trillium Gift of Life Network (TGLN) TOTAL database from June 1, 2006 until May 31, 2009. All DCDs were tracked, including unsuccessful DCD attempts during that time. For the first 36 months after DCD implementation, all Ontario solid organ transplant programs that utilized organs from DCD provided clinical outcome data at one year. Total DCD activity until December 1, 2010 was also tracked. In addition, we compared organ donation and DCD rates across all Canadian jurisdictions and the USA.

RESULTS

For the first 36 months of DCD activity in Ontario, June 1, 2006 to May 31, 2009, there were 67 successful DCDs out of 87 attempted DCDs in 18 Ontario hospitals, resulting in 128 kidney, 41 liver, and 21 lung transplants. The one-year kidney patient and death-censored allograft survivals were 96 and 97%, respectively. Mean (SD) creatinine at 12 months was 150 (108) μmol·L(-1). In 26 (20%) extended criteria donors (ECD-DCD), the one-year creatinine was 206 (158) μmol·L(-1) vs 137 (80) μmol·L(-1) in 102 standard criteria donors (SCD-DCD) (P = 0.002). The one-year liver and lung allograft survivals were 78% and 70%, respectively. Since its implementation four and a half years ago, DCD has accounted for 10.9% of deceased donor activity in Ontario. In 2009, Ontario had a record number of organ donors. Of the 221 deceased donors, 37 (17%) donors were DCD. By December 1, 2010 there were 121 DCD Ontario donors resulting in > 300 solid organ transplants and accounting for 90% of all DCD activity in the country.

CONCLUSION

The rapid update of DCD in Ontario can be attributed to strong proponents in the critical care and transplantation communities with continued support from Trillium Gift of Life Network (TGLN). Ontario is the only province to demonstrate growth in deceased donor rates over the last decade (25% over the last four years), which can be attributed primarily to the success of its DCD activity.

The long-term quality of life of living kidney donors: a multicenter cohort study

Previous studies that described the long-term quality of life of living kidney donors were conducted in single centers, and lacked data on a healthy nondonor comparison group. We conducted a retrospective cohort study to compare the quality of life of 203 kidney donors with 104 healthy nondonor controls using validated scales (including the SF36, 15D and feeling thermometer) and author-developed questions. Participants were recruited from nine transplant centers in Canada, Scotland and Australia. Outcomes were assessed a median of 5.5 years after the time of transplantation (lower and upper quartiles of 3.8 and 8.4 years, respectively). 15D scores (scale of 0 to 1) were high and similar between donors and nondonors (mean 0.93 (standard deviation (SD) 0.09) and 0.94 (SD 0.06), p = 0.55), and were not different when results were adjusted for several prognostic characteristics (p = 0.55). On other scales and author-developed questions, groups performed similarly. Donors to recipients who had an adverse outcome (death, graft failure) had similar quality of life scores as those donors where the recipient did well. Our findings are reassuring for the practice of living transplantation. Those who donate a kidney in centers that use routine pretransplant donor evaluation have good long-term quality of life.

Nucleic acid testing (NAT) of organ donors: is the 'best' test the right test? A consensus conference report

Nucleic acid testing (NAT) for HIV, HBV and HCV shortens the time between infection and detection by available testing. A group of experts was selected to develop recommendations for the use of NAT in the HIV/HBV/HCV screening of potential organ donors. The rapid turnaround times needed for donor testing and the risk of death while awaiting transplantation make organ donor screening different from screening blood-or tissue donors. In donors with no identified risk factors, there is insufficient evidence to recommend routine NAT, as the benefits of NAT may not outweigh the disadvantages of NAT especially when false-positive results can lead to loss of donor organs. For donors with identified behavioral risk factors, NAT should be considered to reduce the risk of transmission and increase organ utilization. Informed consent balancing the risks of donor-derived infection against the risk of remaining on the waiting list should be obtained at the time of candidate listing and again at the time of organ offer. In conclusion, there is insufficient evidence to recommend universal prospective screening of organ donors for HIV, HCV and HBV using current NAT platforms. Further study of viral screening modalities may reduce disease transmission risk without excessive donor loss.

Predicting potential survival benefit of renal transplantation in patients with chronic kidney disease

BACKGROUND

To facilitate decision-making about treatment options for patients with end-stage renal disease considering kidney transplantation, we sought to develop an index for clinical prediction of risk for death.

METHODS

We derived and validated a multivariable survival model predicting time to death in 169,393 patients with end-stage renal disease who were eligible for transplantation. We modified the model into a simple point-system index.

RESULTS

Deaths occurred in 23.5% of the cohort. Twelve variables independently predicted death: age, race, cause of kidney failure, body mass index, comorbid disease, smoking, employment status, serum albumin level, year of first renal replacement therapy, kidney transplantation, time to transplant wait-listing and time on the wait list. The index separated patients into 26 groups having significantly unique five-year survival, ranging from 97.8% in the lowest-risk group to 24.7% in the highest-risk group. The index score was discriminative, with a concordance probability of 0.746 (95% CI 0.741-0.751). Observed survival in the derivation and validation cohorts was similar for each level of index score in 93.9% of patients.

INTERPRETATION

Our prognostic index uses commonly available information to predict mortality accurately in patients with end-stage renal disease. This index could provide valuable quantitative data on survival for clinicians and patients to use when deciding whether to pursue transplantation or remain on dialysis.

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers in Peritoneal Dialysis: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are widely used in clinical practice. The safety and efficacy of these agents in peritoneal dialysis (PD) patients are unclear.

Objectives

We conducted a systematic review to study the safety and efficacy of ACEI and ARB use in PD patients. Primary outcome measures were mortality and cardiovascular (CV) events; secondary outcome measures were renal function, proteinuria, hyperkalemia, and erythropoietin requirement at 3 months.

Methods

We searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, trial registry Web sites, reference lists of eligible and review articles, as well as abstracts from the American Society of Nephrology and Canadian Society of Nephrology meetings. To be eligible, studies had to be randomized controlled trials that allocated PD patients to ACEI and ARB use or to placebo or other antihypertensive medications, included adult patients, and reported on at least one of the outcome measures.

Results

418 citations were identified. Four met the eligibility criteria. Three examined CV events and mortality, of which two studies did not have any events. The third showed no statistically significant difference between control and treatment groups in either CV events or mortality: odds ratio 1.56 [95% confidence interval (CI) 0.24 – 10.05] for mortality and odds ratio 1.00 (95% CI 0.19 – 5.40) for CV events. Two studies reported renal function at 12 months and the weighted mean difference was 0.91 mL/minute/1.73 m2 (95% CI 0.14 – 1.68), favoring ACEI and ARB use.

Conclusions

In PD patients, evidence for the use of ACEIs and ARBs for reduction of mortality and CV events is lacking. Limited data suggest that they slow the loss of residual renal function.

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in peritoneal dialysis: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are widely used in clinical practice. The safety and efficacy of these agents in peritoneal dialysis (PD) patients are unclear.

OBJECTIVES

We conducted a systematic review to study the safety and efficacy of ACEI and ARB use in PD patients. Primary outcome measures were mortality and cardiovascular (CV) events; secondary outcome measures were renal function, proteinuria, hyperkalemia, and erythropoietin requirement at 3 months.

METHODS

We searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, trial registry Web sites, reference lists of eligible and review articles, as well as abstracts from the American Society of Nephrology and Canadian Society of Nephrology meetings. To be eligible, studies had to be randomized controlled trials that allocated PD patients to ACEI and ARB use or to placebo or other antihypertensive medications, included adult patients, and reported on at least one of the outcome measures.

RESULTS

418 citations were identified. Four met the eligibility criteria. Three examined CV events and mortality, of which two studies did not have any events. The third showed no statistically significant difference between control and treatment groups in either CV events or mortality: odds ratio 1.56 [95% confidence interval (CI) 0.24 - 10.05] for mortality and odds ratio 1.00 (95% CI 0.19 - 5.40) for CV events. Two studies reported renal function at 12 months and the weighted mean difference was 0.91 mL/minute/1.73 m(2) (95% CI 0.14 - 1.68), favoring ACEI and ARB use.

CONCLUSIONS

In PD patients, evidence for the use of ACEIs and ARBs for reduction of mortality and CV events is lacking. Limited data suggest that they slow the loss of residual renal function.

Trends in kidney transplantation over the past decade

Kidney transplantation offers patients with end-stage renal disease the greatest potential for increased longevity and enhanced quality of life; however, the demand for kidneys far exceeds the available supply. This has led to an increase in the number of people on waiting lists and an increase in waiting time. In the US, the overall median wait time was 2.85 years in 2004. The projected median waiting time for adult patients awaiting a deceased donor kidney in 2006 is 4.58 years. The renal transplant community has pursued multiple avenues in an attempt to increase the donor pool, but this remains a major challenge. In the last decade, the number of live donor kidney transplants performed in the US and Canada has doubled and represents just over 40% of all donor kidneys. Among deceased donor kidneys, the largest percentage increases were seen in expanded criteria donor and donation after cardiac death kidneys. In the last decade, the age distribution among donors, and among patients on waiting lists or receiving a renal transplant, has shifted towards older age groups. There have been dramatic shifts in baseline immunosuppression with increased usage of induction agents and the nearly universal replacement of azathioprine by mycophenolate. Additionally, tacrolimus use has increased from 13% to 79% at discharge, while ciclosporin (cyclosporine) use has fallen from 76% to 15%. Although 1-year graft survival rates are excellent, only modest improvements have been observed in long-term graft survival rates in the last decade. Thus, efforts have shifted from improving early graft outcomes to altering the natural course of late graft failure. Death of transplant recipients from cardiovascular disease, infection and cancer remains an important limitation in kidney transplantation. Continued success in kidney transplantation will require increased numbers of donors, both living and deceased, as well as reduction in the primary causes of late transplant loss, namely premature patient death with a functioning graft and chronic allograft nephropathy.

The effect of pentoxifylline on proteinuria in diabetic kidney disease: a meta-analysis

BACKGROUND

Pentoxifylline is a potential therapeutic agent for diabetic kidney disease because it has anti-inflammatory, antifibrotic, and hemorheological properties.

STUDY DESIGN

Systematic review and meta-analysis of randomized controlled trials.

SETTING, POPULATION, & INTERVENTION

Adult patients with diabetic kidney disease who received oral pentoxifylline.

SELECTION CRITERIA FOR STUDIES

We searched bibliographic databases for trials involving pentoxifylline that reported proteinuria, glomerular filtration rate, or blood pressure.

OUTCOMES

The primary outcome measure was the effect of pentoxifylline on proteinuria stratified by whether pentoxifylline was compared with renin-angiotensin system blockade.

RESULTS

10 studies including a total of 476 participants with a median duration of 6 months were identified. Pentoxifylline significantly decreased proteinuria (weighted mean difference, -278 mg/d of protein; 95% confidence interval [CI], -398 to -159; P < 0.001) compared with placebo or usual care. Compared with captopril, the decrease in proteinuria with pentoxifylline was similar (weighted mean difference, 0 mg/d of protein; 95% CI, -17 to 18; P = 0.9). Secondary analysis showed that patients with microalbuminuria had a nonsignificant decrease in protein excretion (weighted mean difference, -87 mg/d; 95% CI, -201 to 27; P = 0.1), whereas those with overt proteinuria (protein > 300 mg/d) had a significant decrease (weighted mean difference, -502 mg/d; 95% CI, -805 to -198; P = 0.001). No significant changes in systolic or diastolic blood pressure or glomerular filtration rate were found.

LIMITATIONS

Quality scores of studies were low, and there was significant heterogeneity.

CONCLUSIONS

Available evidence suggests that pentoxifylline may decrease proteinuria in patients with diabetic nephropathy. To confirm these findings, large high-quality studies are required.