Kidney Paired Donation Chains Initiated by Deceased Donors.

Introduction: Rather than generating 1 transplant by directly donating to a candidate on the waitlist, deceased donors (DDs) could achieve additional transplants by donating to a candidate in a kidney paired donation (KPD) pool, thereby, initiating a chain that ends with a living donor (LD) donating to a candidate on the waitlist. We model outcomes arising from various strategies that allow DDs to initiate KPD chains. Methods: We base simulations on actual 2016 to 2017 US DD and waitlist data and use simulated KPD pools to model DD-initiated KPD chains. We also consider methods to assess and overcome the primary criticism of this approach, namely the potential to disadvantage blood type O-waitlisted candidates. Results: Compared with shorter DD-initiated KPD chains, longer chains increase the number of KPD transplants by up to 5% and reduce the number of DDs allocated to the KPD pool by 25%. These strategies increase the overall number of blood type O transplants and make LDs available to candidates on the waitlist. Restricting allocation of blood type O DDs to require ending KPD chains with LD blood type O donations to the waitlist markedly reduces the number of KPD transplants achieved. Conclusion: Allocating fewer than 3% of DD to initiate KPD chains could increase the number of kidney transplants by up to 290 annually. Such use of DDs allows additional transplantation of highly sensitized and blood type O KPD candidates. Collectively, patients of each blood type, including blood type O, would benefit from the proposed strategies.

COVID-19 Risk Factors and Mortality Outcomes Among Medicare Patients Receiving Long-term Dialysis.

Importance: There is a need for studies to evaluate the risk factors for COVID-19 and mortality among the entire Medicare long-term dialysis population using Medicare claims data. Objective: To identify risk factors associated with COVID-19 and mortality in Medicare patients undergoing long-term dialysis. Design, Setting, and Participants: This retrospective, claims-based cohort study compared mortality trends of patients receiving long-term dialysis in 2020 with previous years (2013-2019) and fit Cox regression models to identify risk factors for contracting COVID-19 and postdiagnosis mortality. The cohort included the national population of Medicare patients receiving long-term dialysis in 2020, derived from clinical and administrative databases. COVID-19 was identified through Medicare claims sources. Data were analyzed on May 17, 2021. Main Outcomes and Measures: The 2 main outcomes were COVID-19 and all-cause mortality. Associations of claims-based risk factors with COVID-19 and mortality were investigated prediagnosis and postdiagnosis. Results: Among a total of 498 169 Medicare patients undergoing dialysis (median [IQR] age, 66 [56-74] years; 215 935 [43.1%] women and 283 227 [56.9%] men), 60 090 (12.1%) had COVID-19, among whom 15 612 patients (26.0%) died. COVID-19 rates were significantly higher among Black (21 787 of 165 830 patients [13.1%]) and Hispanic (13 530 of 86 871 patients [15.6%]) patients compared with non-Black patients (38 303 of 332 339 [11.5%]), as well as patients with short (ie, 1-89 days; 7738 of 55 184 patients [14.0%]) and extended (ie, ≥90 days; 10 737 of 30 196 patients [35.6%]) nursing home stays in the prior year. Adjusting for all other risk factors, residing in a nursing home 1 to 89 days in the prior year was associated with a higher hazard for COVID-19 (hazard ratio [HR] vs 0 days, 1.60; 95% CI 1.56-1.65) and for postdiagnosis mortality (HR, 1.31; 95% CI, 1.25-1.37), as was residing in a nursing home for an extended stay (COVID-19: HR, 4.48; 95% CI, 4.37-4.59; mortality: HR, 1.12; 95% CI, 1.07-1.16). Black race (HR vs non-Black: HR, 1.25; 95% CI, 1.23-1.28) and Hispanic ethnicity (HR vs non-Hispanic: HR, 1.68; 95% CI, 1.64-1.72) were associated with significantly higher hazards of COVID-19. Although home dialysis was associated with lower COVID-19 rates (HR, 0.77; 95% CI, 0.75-0.80), it was associated with higher mortality (HR, 1.18; 95% CI, 1.11-1.25). Conclusions and Relevance: These results shed light on COVID-19 risk factors and outcomes among Medicare patients receiving long-term chronic dialysis and could inform policy decisions to mitigate the significant extra burden of COVID-19 and death in this population.

Acute Kidney Injury Requiring Dialysis and Incident Dialysis Patient Outcomes in US Outpatient Dialysis Facilities.

BACKGROUND AND OBJECTIVES: About 30% of patients with AKI may require ongoing dialysis in the outpatient setting after hospital discharge. A 2017 Centers for Medicare & Medicaid Services policy change allows Medicare beneficiaries with AKI requiring dialysis to receive outpatient treatment in dialysis facilities. Outcomes for these patients have not been reported. We compare patient characteristics and mortality among patients with AKI requiring dialysis and patients without AKI requiring incident dialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We used a retrospective cohort design with 2017 Medicare claims to follow outpatients with AKI requiring dialysis and patients without AKI requiring incident dialysis up to 365 days. Outcomes are unadjusted and adjusted mortality using Kaplan-Meier estimation for unadjusted survival probability, Poisson regression for monthly mortality, and Cox proportional hazards modeling for adjusted mortality. RESULTS: In total, 10,821 of 401,973 (3%) Medicare patients requiring dialysis had at least one AKI claim, and 52,626 patients were Medicare patients without AKI requiring incident dialysis. Patients with AKI requiring dialysis were more likely to be White (76% versus 70%), non-Hispanic (92% versus 87%), and age 60 or older (82% versus 72%) compared with patients without AKI requiring incident dialysis. Unadjusted mortality was markedly higher for patients with AKI requiring dialysis compared with patients without AKI requiring incident dialysis. Adjusted mortality differences between both cohorts persisted through month 4 of the follow-up period (all P=0.01), then, they declined and were no longer statistically significant. Adjusted monthly mortality stratified by Black and other race between patients with AKI requiring dialysis and patients without AKI requiring incident dialysis was lower throughout month 4 (1.5 versus 0.60, 1.20 versus 0.84, 1.00 versus 0.80, and 0.95 versus 0.74; all P<0.001), which persisted through month 7. Overall adjusted mortality risk was 22% higher for patients with AKI requiring dialysis (1.22; 95% confidence interval, 1.17 to 1.27). CONCLUSIONS: In fully adjusted analyses, patients with AKI requiring dialysis had higher early mortality compared with patients without AKI requiring incident dialysis, but these differences declined after several months. Differences were also observed by age, race, and ethnicity within both patient cohorts.

Deceased donors as nondirected donors in kidney paired donation.

As proof of concept, we simulate a revised kidney allocation system that includes deceased donor (DD) kidneys as chain-initiating kidneys (DD-CIK) in a kidney paired donation pool (KPDP), and estimate potential increases in number of transplants. We consider chains of length 2 in which the DD-CIK gives to a candidate in the KPDP, and that candidate's incompatible donor donates to theDD waitlist. In simulations, we vary initial pool size, arrival rates of candidate/donor pairs and (living) nondirected donors (NDDs), and delay time from entry to the KPDP until a candidate is eligible to receive a DD-CIK. Using data on candidate/donor pairs and NDDs from the Alliance for Paired Kidney Donation, and the actual DDs from the Scientific Registry of Transplant Recipients (SRTR) data, simulations extend over 2 years. With an initial pool of 400, respective candidate and NDD arrival rates of 2 per day and 3 per month, and delay times for access to DD-CIK of 6 months or less, including DD-CIKs increases the number of transplants by at least 447 over 2 years, and greatly reduces waiting times of KPDP candidates. Potential effects on waitlist candidates are discussed as are policy and ethical issues.

Nephrology care prior to end-stage renal disease and outcomes among new ESRD patients in the USA.

BACKGROUND: Longer nephrology care before end-stage renal disease (ESRD) has been linked with better outcomes. METHODS: We investigated whether longer pre-end-stage renal disease (ESRD) nephrology care was associated with lower mortality at both the patient and state levels among 443 761 incident ESRD patients identified in the USA between 2006 and 2010. RESULTS: Overall, 33% of new ESRD patients had received no prior nephrology care, while 28% had received care for >12 months. At the patient level, predictors of >12 months of nephrology care included having health insurance, white race, younger age, diabetes, hypertension and US region. Longer pre-ESRD nephrology care was associated with lower first-year mortality (adjusted hazard ratio = 0.58 for >12 months versus no care; 95% confidence interval 0.57-0.59), higher albumin and hemoglobin, choice of peritoneal dialysis and native fistula and discussion of transplantation options. Living in a state with a 10% higher proportion of patients receiving >12 months of pre-ESRD care was associated with a 9.3% lower relative mortality rate, standardized for case mix (R (2) = 0.47; P < 0.001). CONCLUSIONS: This study represents the largest cohort of incident ESRD patients to date. Although we did not follow patients before ESRD onset, our findings, both at the individual patient and state levels, reflect the importance of early nephrology care among those with chronic kidney disease.

Risk Adjustment and the Assessment of Disparities in Dialysis Mortality Outcomes.

Standardized mortality ratios (SMRs) reported by Medicare compare mortality at individual dialysis facilities with the national average, and are currently adjusted for race. However, whether the adjustment for race obscures or clarifies disparities in quality of care for minority groups is unknown. Cox model-based SMRs were computed with and without adjustment for patient race for 5920 facilities in the United States during 2010. The study population included virtually all patients treated with dialysis during this period. Without race adjustment, facilities with higher proportions of black patients had better survival outcomes; facilities with the highest percentage of black patients (top 10%) had overall mortality rates approximately 7% lower than expected. After adjusting for within-facility racial differences, facilities with higher proportions of black patients had poorer survival outcomes among black and non-black patients; facilities with the highest percentage of black patients (top 10%) had mortality rates approximately 6% worse than expected. In conclusion, accounting for within-facility racial differences in the computation of SMR helps to clarify disparities in quality of health care among patients with ESRD. The adjustment that accommodates within-facility comparisons is key, because it could also clarify relationships between patient characteristics and health care provider outcomes in other settings.

A Dirichlet process mixture model for survival outcome data: assessing nationwide kidney transplant centers.

Mortality rates are probably the most important indicator for the performance of kidney transplant centers. Motivated by the national evaluation of mortality rates at kidney transplant centers in the USA, we seek to categorize the transplant centers based on the mortality outcome. We describe a Dirichlet process model and a Dirichlet process mixture model with a half-cauchy prior for the estimation of the risk-adjusted effects of the transplant centers, with strategies for improving the model performance, interpretability, and classification ability. We derive statistical measures and create graphical tools to rate transplant centers and identify outlying groups of centers with exceptionally good or poor performance. The proposed method was evaluated through simulation and then applied to assess kidney transplant centers from a national organ failure registry.

Liver regeneration after living donor transplantation: adult-to-adult living donor liver transplantation cohort study.

Adult-to-adult living donors and recipients were studied to characterize patterns of liver growth and identify associated factors in a multicenter study. Three hundred and fifty donors and 353 recipients in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL) receiving transplants between March 2003 and February 2010 were included. Potential predictors of 3-month liver volume included total and standard liver volumes (TLV and SLV), Model for End-Stage Liver Disease (MELD) score (in recipients), the remnant and graft size, remnant-to-donor and graft-to-recipient weight ratios (RDWR and GRWR), remnant/TLV, and graft/SLV. Among donors, 3-month absolute growth was 676 ± 251 g (mean ± SD), and percentage reconstitution was 80% ± 13%. Among recipients, GRWR was 1.3% ± 0.4% (8 < 0.8%). Graft weight was 60% ± 13% of SLV. Three-month absolute growth was 549 ± 267 g, and percentage reconstitution was 93% ± 18%. Predictors of greater 3-month liver volume included larger patient size (donors and recipients), larger graft volume (recipients), and larger TLV (donors). Donors with the smallest remnant/TLV ratios had larger than expected growth but also had higher postoperative bilirubin and international normalized ratio at 7 and 30 days. In a combined donor-recipient analysis, donors had smaller 3-month liver volumes than recipients adjusted for patient size, remnant or graft volume, and TLV or SLV (P = 0.004). Recipient graft failure in the first 90 days was predicted by poor graft function at day 7 (HR = 4.50, P = 0.001) but not by GRWR or graft fraction (P > 0.90 for each). Both donors and recipients had rapid yet incomplete restoration of tissue mass in the first 3 months, and this confirmed previous reports. Recipients achieved a greater percentage of expected total volume. Patient size and recipient graft volume significantly influenced 3-month volumes. Importantly, donor liver volume is a critical predictor of the rate of regeneration, and donor remnant fraction affects postresection function. Liver Transpl 21:79-88, 2015. © 2014 AASLD.

Patient selection and volume in the era surrounding implementation of Medicare conditions of participation for transplant programs.

OBJECTIVE: To evaluate evidence of practice changes affecting kidney transplant program volumes, and donor, recipient and candidate selection in the era surrounding the introduction of Centers for Medicare and Medicaid Services (CMS) conditions of participation (CoPs) for organ transplant programs. DATA: Scientific Registry of Transplant Recipients; CMS ESRD and Medicare claims databases. DESIGN: Retrospective analysis of national registry data. METHODS: A Cox proportional hazards model of 1-year graft survival was used to derive risks associated with deceased-donor kidney transplants performed from 2001 to 2010. FINDINGS: Among programs with ongoing noncompliance with the CoPs, kidney transplant volumes declined by 38 percent (n = 766) from 2006 to 2011, including a 55 percent drop in expanded criteria donor transplants. Volume increased by 6 percent (n = 638) among programs remaining in compliance. Aggregate risk of 1-year graft failure increased over time due to increasing recipient age and obesity, and longer ESRD duration. CONCLUSIONS: Although trends in aggregate risk of 1-year kidney graft loss do not indicate that the introduction of the CoPs has systematically reduced opportunities for marginal candidates or that there has been a systematic shift away from utilization of higher risk deceased donor kidneys, total volume and expanded criteria donor utilization decreased overall among programs with ongoing noncompliance.

Liver transplant recipient survival benefit with living donation in the model for endstage liver disease allocation era.

UNLABELLED: Receipt of a living donor liver transplant (LDLT) has been associated with improved survival compared with waiting for a deceased donor liver transplant (DDLT). However, the survival benefit of liver transplant has been questioned for candidates with Model for Endstage Liver Disease (MELD) scores <15, and the survival advantage of LDLT has not been demonstrated during the MELD allocation era, especially for low MELD patients. Transplant candidates enrolled in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study after February 28, 2002 were followed for a median of 4.6 years. Starting at the time of presentation of the first potential living donor, mortality for LDLT recipients was compared to mortality for patients who remained on the waiting list or received DDLT (no LDLT group) according to categories of MELD score (<15 or ≥ 15) and diagnosis of hepatocellular carcinoma (HCC). Of 868 potential LDLT recipients (453 with MELD <15; 415 with MELD ≥ 15 at entry), 712 underwent transplantation (406 LDLT; 306 DDLT), 83 died without transplant, and 73 were alive without transplant at last follow-up. Overall, LDLT recipients had 56% lower mortality (hazard ratio [HR] = 0.44, 95% confidence interval [CI] 0.32-0.60; P < 0.0001). Among candidates without HCC, mortality benefit was seen both with MELD <15 (HR = 0.39; P = 0.0003) and MELD ≥ 15 (HR = 0.42; P = 0.0006). Among candidates with HCC, a benefit of LDLT was not seen for MELD <15 (HR = 0.82, P = 0.65) but was seen for MELD ≥ 15 (HR = 0.29, P = 0.043). CONCLUSION: Across the range of MELD scores, patients without HCC derived a significant survival benefit when undergoing LDLT rather than waiting for DDLT in the MELD liver allocation era. Low MELD candidates with HCC may not benefit from LDLT.

Hospitalization rates before and after adult-to-adult living donor or deceased donor liver transplantation.

OBJECTIVE: To compare rates of hospitalization before and after adult-to-adult living donor liver transplant (LDLT) and deceased donor liver transplant (DDLT). SUMMARY BACKGROUND DATA: LDLT recipients have been reported to have lower mortality but a higher complication rate than DDLT recipients. The higher complication rate may be associated with greater consumption of inpatient hospital resources and a higher burden of disease for LDLT recipients. METHODS: Data from the 9-center Adult-to-Adult Living Donor Liver Transplantation retrospective cohort study were analyzed to determine pretransplant, transplant, and posttransplant hospitalizations among LDLT candidates (potential living donor was evaluated) who received LDLT or DDLT. Hospital days and admission rates for LDLT and DDLT patients were calculated per patient-year at risk, starting from the date of initial potential donor history and physical examination. Rates were compared using overdispersed Poisson regression models. RESULTS: Among 806 candidates, 384 received LDLT and 215 received DDLT. In addition to the 599 transplants, there were 1913 recipient hospitalizations (485 pretransplant; 1428 posttransplant). Mean DDLT recipient pretransplant, transplant, and posttransplant lengths of stay were 5.8 +/- 6.3, 27.0 +/- 32.6, and 9.0 +/- 14.1 days, respectively, and for LDLT were 4.1 +/- 3.7, 21.4 +/- 24.3, and 7.8 +/- 11.4 days, respectively. Compared with DDLT, LDLT recipients had significantly lower adjusted pretransplant hospital day and admission rates, but significantly higher posttransplant rates. Significantly higher LDLT admission rates were observed for biliary tract morbidity throughout the second posttransplant year. Overall hospitalization rates starting from the point of potential donor evaluation were significantly higher for eventual recipients of LDLT. CONCLUSIONS: LDLT recipients, despite lower acuity of disease, have higher hospitalization requirements when compared with DDLT recipients. Continuing efforts are warranted to reduce the incidence of complications requiring post-LDLT inpatient admission, with particular emphasis on biliary tract issues.

Differences in mortality among Mexican-American, Puerto Rican, and Cuban-American dialysis patients in the United States.

BACKGROUND: The Hispanic ethnic group is heterogeneous, with distinct genetic, cultural, and socioeconomic characteristics, but most prior studies of patients with end-stage renal disease focus on the overall Hispanic ethnic group without further granularity. We examined survival differences among Mexican-American, Puerto Rican, and Cuban-American dialysis patients in the United States. STUDY DESIGN: Prospective observational study. SETTING & PARTICIPANTS: Data from individuals randomly selected for the End-Stage Renal Disease Clinical Performance Measures Project (2001 to 2005) were examined. Mexican-American (n = 2,742), Puerto Rican (n = 838), Cuban-American (n = 145), and Hispanic-other dialysis patients (n = 942) were compared with each other and with non-Hispanic (n = 33,076) dialysis patients in the United States. PREDICTORS: Patient characteristics of interest included ethnicity/race, comorbidities, and specific available laboratory values. OUTCOMES: The major outcome of interest was mortality. RESULTS: In the fully adjusted multivariable model, 2-year mortality risk was significantly lower for the Mexican-American and Hispanic-other groups compared with non-Hispanics (adjusted hazard ratio, 0.79; 95% confidence interval, 0.73 to 0.85; adjusted hazard ratio, 0.81; 95% confidence interval, 0.71 to 0.92, respectively). Differences in 2-year mortality rates within the Hispanic ethnic groups were statistically significant (P = 0.004) and ranged from 21% lower mortality in Mexican Americans to 3% higher mortality in Puerto Ricans compared with non-Hispanics. LIMITATIONS: Include those inherent to an observational study, potential ethnic group misclassification, and small sample sizes for some Hispanic subgroups. CONCLUSION: Mexican-American and Hispanic-other dialysis patients have a survival advantage compared with non-Hispanics. Furthermore, Mexican Americans, Cuban Americans, and Hispanic others had a survival advantage compared with their Puerto Rican counterparts. Future research should continue to examine subgroups within Hispanic ethnicity to understand underlying reasons for observed differences that may be masked by examining the Hispanic ethnic group as only a single entity.

Deceased-donor characteristics and the survival benefit of kidney transplantation.

CONTEXT: Transplantation using kidneys from deceased donors who meet the expanded criteria donor (ECD) definition (age > or =60 years or 50 to 59 years with at least 2 of the following: history of hypertension, serum creatinine level >1.5 mg/dL [132.6 micromol/L], and cerebrovascular cause of death) is associated with 70% higher risk of graft failure compared with non-ECD transplants. However, if ECD transplants offer improved overall patient survival, inferior graft outcome may represent an acceptable trade-off. OBJECTIVE: To compare mortality after ECD kidney transplantation vs that in a combined standard-therapy group of non-ECD recipients and those still receiving dialysis. DESIGN, SETTING, AND PATIENTS: Retrospective cohort study using data from a US national registry of mortality and graft outcomes among kidney transplant candidates and recipients. The cohort included 109,127 patients receiving dialysis and added to the kidney waiting list between January 1, 1995, and December 31, 2002, and followed up through July 31, 2004. MAIN OUTCOME MEASURE: Long-term (3-year) relative risk of mortality for ECD kidney recipients vs those receiving standard therapy, estimated using time-dependent Cox regression models. RESULTS: By end of follow-up, 7790 ECD kidney transplants were performed. Because of excess ECD recipient mortality in the perioperative period, cumulative survival did not equal that of standard-therapy patients until 3.5 years posttransplantation. Long-term relative mortality risk was 17% lower for ECD recipients (relative risk, 0.83; 95% confidence interval, 0.77-0.90; P<.001). Subgroups with significant ECD survival benefit included patients older than 40 years, both sexes, non-Hispanics, all races, unsensitized patients, and those with diabetes or hypertension. In organ procurement organizations (OPOs) with long median waiting times (>1350 days), ECD recipients had a 27% lower risk of death (relative risk, 0.73; 95% confidence interval, 0.64-0.83; P<.001). In areas with shorter waiting times, only recipients with diabetes demonstrated an ECD survival benefit. CONCLUSIONS: ECD kidney transplants should be offered principally to candidates older than 40 years in OPOs with long waiting times. In OPOs with shorter waiting times, in which non-ECD kidney transplant availability is higher, candidates should be counseled that ECD survival benefit is observed only for patients with diabetes.

Outcomes of 385 adult-to-adult living donor liver transplant recipients: a report from the A2ALL Consortium.

OBJECTIVE: The objective of this study was to characterize the patient population with respect to patient selection, assess surgical morbidity and graft failures, and analyze the contribution of perioperative clinical factors to recipient outcome in adult living donor liver transplantation (ALDLT). SUMMARY BACKGROUND DATA: Previous reports have been center-specific or from large databases lacking detailed variables. The Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL) represents the first detailed North American multicenter report of recipient risk and outcome aiming to characterize variables predictive of graft failure. METHODS: Three hundred eighty-five ALDLT recipients transplanted at 9 centers were studied with analysis of over 35 donor, recipient, intraoperative, and postoperative variables. Cox regression models were used to examine the relationship of variables to the risk of graft failure. RESULTS: Ninety-day and 1-year graft survival were 87% and 81%, respectively. Fifty-one (13.2%) grafts failed in the first 90 days. The most common causes of graft failure were vascular thrombosis, primary nonfunction, and sepsis. Biliary complications were common (30% early, 11% late). Older recipient age and length of cold ischemia were significant predictors of graft failure. Center experience greater than 20 ALDLT was associated with a significantly lower risk of graft failure. Recipient Model for End-stage Liver Disease score and graft size were not significant predictors. CONCLUSIONS: This multicenter A2ALL experience provides evidence that ALDLT is a viable option for liver replacement. Older recipient age and prolonged cold ischemia time increase the risk of graft failure. Outcomes improve with increasing center experience.

Thoracic organ transplantation in the United States, 1994-2003.

Using OPTN/SRTR data, this article reviews the state of thoracic organ transplantation in 2003 and the previous decade. Time spent on the heart waiting list has increased significantly over the last decade. The percentage of patients awaiting heart transplantation for >2 years increased from 23% in 1994 to 49% by 2003. However, there has been a general decline in heart waiting list death rates over the decade. In 2003, the lung transplant waiting list reached a record high of 3,836 registrants, up slightly from 2002 and more than threefold since 1994. One-year patient survival for those receiving lungs in 2002 was 82%, a statistically significant improvement from 2001 (78%). The number of patients awaiting a heart-lung transplant, declining since 1998, reached 189 in 2003. Adjusted patient survival for heart-lung recipients is consistently worse than the corresponding rate for isolated lung recipients, primarily due to worse outcomes for heart-lung recipients with congenital heart disease. A new lung allocation system, approved in June 2004, derives from the survival benefit of transplantation with consideration of urgency based on waiting list survival, instead of being based solely on waiting time. A goal of the policy is to minimize deaths on the waiting list.

Analytical approaches for transplant research, 2004.

This article provides detailed explanations of the methods frequently employed in outcomes analyses performed by the Scientific Registry of Transplant Recipients (SRTR). All aspects of the analytical process are discussed, including cohort selection, post-transplant follow-up analysis, outcome definition, ascertainment of events, censoring, and adjustments. The methods employed for descriptive analyses are described, such as unadjusted mortality rates and survival probabilities, and the estimation of covariant effects through regression modeling. A section on transplant waiting time focuses on the kidney and liver waiting lists, pointing out the different considerations each list requires and the larger questions that such analyses raise. Additionally, this article describes specialized modeling strategies recently designed by the SRTR and aimed at specific organ allocation issues. The article concludes with a description of simulated allocation modeling (SAM), which has been developed by the SRTR for three organ systems: liver, thoracic organs, and kidney-pancreas. SAMs are particularly useful for comparing outcomes for proposed national allocation policies. The use of SAMs has already helped in the development and implementation of a new policy for liver candidates with high MELD scores to be offered organs regionally before the organs are offered to candidates with low MELD scores locally.

Improvements in dialysis patient mortality are associated with improvements in urea reduction ratio and hematocrit, 1999 to 2002.

BACKGROUND: Benefits in terms of reductions in mortality corresponding to improvements in Kidney Disease Outcomes Quality Initiative (K/DOQI) compliance for adequacy of dialysis dose and anemia control have not been documented in the literature. We studied changes in achieving K/DOQI guidelines at the facility level to determine whether those changes are associated with corresponding changes in mortality. METHODS: Adjusted mortality and fractions of patients achieving K/DOQI guidelines for urea reduction ratios (URRs; > or =65%) and hematocrit levels (> or =33%) were computed for 2,858 dialysis facilities from 1999 to 2002 using national data for patients with end-stage renal disease. Linear and Poisson regression were used to study the relationship between K/DOQI compliance and mortality and between changes in compliance and changes in mortality. RESULTS: In 2002, facilities in the lowest quintile of K/DOQI compliance for URR and hematocrit guidelines had 22% and 14% greater mortality rates (P < 0.0001) than facilities in the highest quintile, respectively. A 10-percentage point increase in fraction of patients with a URR of 65% or greater was associated with a 2.2% decrease in mortality (P = 0.0006), and a 10-percentage point increase in percentage of patients with a hematocrit of 33% or greater was associated with a 1.5% decrease in mortality (P = 0.003). Facilities in the highest tertiles of improvement for URR and hematocrit had a change in mortality rates that was 15% better than those observed for facilities in the lowest tertiles (P < 0.0001). CONCLUSION: Both current practice and changes in practices with regard to achieving anemia and dialysis-dose guidelines are associated significantly with mortality outcomes at the dialysis-facility level.

High dialysis dose is associated with lower mortality among women but not among men.

BACKGROUND: Several observational studies reported lower mortality risk among hemodialysis patients treated with doses greater than the standard dose. The present study evaluates, with observational data, the secondary randomized Hemodialysis (HEMO) Study finding that greater dialysis dose may benefit women, but not men. METHODS: Data from 74,120 US hemodialysis patients starting end-stage renal disease therapy were analyzed. Patients were classified into 1 of 5 categories of hemodialysis dose according to their average urea reduction ratio (URR), and their relative risk (RR) for mortality was evaluated by using Cox proportional hazards models. Similar analyses using equilibrated Kt/V were completed for 10,816 hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) in 7 countries. RESULTS: For both men and women, RR was substantially lower in the URR 70%-to-75% category compared with the URR 65%-to-70% category. Among women, RR in the URR greater-than-75% category was significantly lower compared with the URR 70%-to-75% group (P < 0.0001); however, no further association with mortality risk was observed for the greater-than-75% category among men (P = 0.22). RR associated with doses greater than the Kidney Disease Outcomes Quality Initiative guidelines (URR > or = 65%) was significantly different for men compared with women (P < 0.01). Similar differences by sex were observed in DOPPS analyses. CONCLUSION: The agreement of these observational studies with the HEMO Study supports the existence of a survival benefit from greater dialysis doses for women, but not for men. Responses to greater dialysis dose by sex deserve additional study to explain these differences.

Pediatric transplantation.

Analysis of the OPTN/SRTR database demonstrates that, in 2002, pediatric recipients accounted for 7% of all recipients, while pediatric individuals accounted for 14% of deceased organ donors. For children fortunate enough to receive a transplant, there has been continued improvement in outcomes following all forms of transplantation. Current 1-year graft survival is generally excellent, with survival rates following transplantation in many cases equaling or exceeding those of all other recipients. In renal transplantation, despite excellent early graft survival, there is evidence that long-term graft survival for adolescent recipients is well below that of other recipients. A causative role for noncompliance is possible. While the significant improvements in graft and patient survival are laudable, waiting list mortality remains excessive. Pediatric candidates awaiting liver, intestine, and thoracic transplantation face mortality rates generally greater than those of their adult counterparts. This finding is particularly pronounced in patients aged 5 years and younger. While mortality awaiting transplantation is an important consideration in refining organ allocation strategies, it is important to realize that other issues, in addition to mortality, are critical for children. Consideration of the impact of end-stage organ disease on growth and development is often equally important, both while awaiting and after transplantation.

Analytical approaches for transplant research.

It is highly desirable to base decisions designed to improve medical practice or organ allocation policies on the analyses of the most recent data available. Yet there is often a need to balance this desire with the added value of evaluating long-term outcomes (e.g. 5-year mortality rates), which requires the use of data from earlier years. This article explains the methods used by the Scientific Registry of Transplant Recipients in order to achieve these goals simultaneously. The analysis of waiting list and transplant outcomes depends strongly on statistical methods that can combine data from different cohorts of patients that have been followed for different lengths of time. A variety of statistical methods have been designed to address these goals, including the Kaplan-Meier estimator, Cox regression models, and Poisson regression. An in-depth description of the statistical methods used for calculating waiting times associated with the various types of organ transplants is provided. Risk of mortality and graft failure, adjusted analyses, cohort selection, and the many complicating factors surrounding the calculation of follow-up time for various outcomes analyses are also examined.