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.

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.

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.