National trends over 25 years in pediatric kidney transplant outcomes.

Objective: To investigate changes in pediatric kidney transplant outcomes over time and potential variations in these changes between the early and late posttransplant periods and across subgroups based on recipient, donor, and transplant characteristics.

Methods: Using multiple logistic regression and multivariable Cox models, graft and patient outcomes were analyzed in 17,446 pediatric kidney-only transplants performed in the United States between 1987 and 2012.

Results: Ten-year patient and graft survival rates were 90.

Histologic phenotype on 1-year posttransplantation biopsy and allograft survival in HLA-incompatible kidney transplants.

Background: The correlation between histopathologic phenotypes and allograft outcomes among patients desensitized for donor-specific antibody (HLA-incompatible) is unknown.

Methods: We analyzed 1-year biopsies from desensitized recipients transplanted between 1999 and 2010 and estimated graft survival for each histologic phenotype identified. Median time posttransplant for the 1-year biopsy was 367 days (interquartile range 357-388 days) and median follow-up of all patients post-1-year biopsy was 42 months (interquartile range 19.

Risk of end-stage renal disease following live kidney donation.

Importance: Risk of end-stage renal disease (ESRD) in kidney donors has been compared with risk faced by the general population, but the general population represents an unscreened, high-risk comparator. A comparison to similarly screened healthy nondonors would more properly estimate the sequelae of kidney donation.

Objectives: To compare the risk of ESRD in kidney donors with that of a healthy cohort of nondonors who are at equally low risk of renal disease and free of contraindications to live donation and to stratify these comparisons by patient demographics.

National assessment of early biliary complications following liver transplantation: incidence and outcomes.

Despite improved overall liver transplant outcomes, biliary complications remain a significant cause of morbidity. A national data set linking transplant registry and Medicare claims data for 17,012 liver transplant recipients was used to identify all recipients with a posttransplant biliary diagnosis code within the first 6 months after transplantation. Patients were further categorized as follows: a diagnosis without a procedure, a diagnosis and an associated radiological or endoscopic procedure, or a diagnosis treated with surgery.

Perioperative complications after live-donor hepatectomy.

Current studies of complications following donor hepatectomy may not be generalizable to all hospitals performing this procedure. To address this, live liver donors were identified in the Nationwide Inpatient Sample (2000-2008). Complications after donor hepatectomy were categorized using International Classification of Diseases, Ninth Revision codes and risk factors for complications were tested using logistic regression.

Sequelae of early hospital readmission after kidney transplantation.

We recently elucidated risk factors for early hospital readmission (EHR) following kidney transplantation (KT). We now sought to quantify the independent associations between EHR and post-KT outcomes, including late hospital readmission (LHR: 1 year after EHR window), death-censored graft loss and mortality, among Medicare-primary KT recipients (2000-2005). Of 32961 KT recipients, 7.

Eculizumab prevents recurrent antiphospholipid antibody syndrome and enables successful renal transplantation.

Renal transplantation in patients with antiphospholipid antibodies has historically proven challenging due to increased risk for thrombosis and allograft failure. This is especially true for patients with antiphospholipid antibody syndrome (APS) and its rare subtype, the catastrophic antiphospholipid antibody syndrome (CAPS). Since a critical mechanism of thrombosis in APS/CAPS is one mediated by complement activation, we hypothesized that preemptive treatment with the terminal complement inhibitor, eculizumab, would reduce the extent of vascular injury and thrombosis, enabling renal transplantation for patients in whom it would otherwise be contraindicated.

Lipid control in patients with coronary heart disease treated in primary care or cardiology clinics.

Background: Guidelines recommend low-density lipoprotein-cholesterol (LDL-C) target of <70 mg/dL in patients with coronary disease. However, this goal is not achieved in many patients.

Objectives: We compared LDL-C control in patients with coronary disease treated by a primary care physician or with the addition of a cardiologist.

Consistency of racial variation in medical outcomes among publicly and privately insured living kidney donors.

Background: Racial disparities in health outcomes after living donation have been reported, but generalizability is not known.

Methods: We linked Organ Procurement and Transplantation Network (OPTN) registry data for 4,007 living kidney donors in 1987 to 2008 with Medicare billing claims (2000-2008). Cox regression with left and right censoring was used to estimate the frequencies and relative risks of postdonation medical diagnoses according to race.

Assessing variation in the costs of care among patients awaiting liver transplantation.

Previous economic analyses of liver transplantation have focused on the cost of the transplant and subsequent care. Accurate characterization of the pretransplant costs, indexed to severity of illness, is needed to assess the economic burden of liver disease. A novel data set linking Medicare claims with transplant registry data for 15,710 liver transplant recipients was used to determine average monthly waitlist spending (N = 249,434 waitlist months) using multivariable linear regression models to adjust for recipient characteristics including Model for End-Stage Liver Disease (MELD) score.

Immunosuppression regimen and the risk of acute rejection in HIV-infected kidney transplant recipients.

Background: Kidney transplantation (KT) is the treatment for end-stage renal disease in appropriate HIV-positive individuals. However, acute rejection (AR) rates are over twice those of HIV-negative recipients.

Methods: To better understand optimal immunosuppression for HIV-positive KT recipients, we studied associations between immunosuppression regimen, AR at 1 year, and survival in 516 HIV-positive and 93,027 HIV-negative adult kidney-only recipients using Scientific Registry of Transplant Recipients data from 2003 to 2011.

Frailty and falls among adult patients undergoing chronic hemodialysis: a prospective cohort study.

Background: Patients undergoing hemodialysis are at high risk of falls, with subsequent complications including fractures, loss of independence, hospitalization, and institutionalization. Factors associated with falls are poorly understood in this population. We hypothesized that insights derived from studies of the elderly might apply to adults of all ages undergoing hemodialysis; we focused on frailty, a phenotype of physiological decline strongly associated with falls in the elderly.

Comparison of mortality in patients with coronary or peripheral artery disease following the first vascular intervention.

Objectives: Patients with peripheral artery disease (PAD) less frequently achieve secondary prevention goals compared with patients with coronary artery disease (CAD). We aimed to compare mortality rates in patients with PAD and CAD following first vascular intervention.

Patients And Methods: Patients 18 years of age or older without a history of cardiovascular disease, who underwent first coronary or lower limb vascular intervention between 2002 and 2010, were included in this study.

The approximability of shortest path-based graph orientations of protein-protein interaction networks.

The graph orientation problem calls for orienting the edges of an undirected graph so as to maximize the number of prespecified source-target vertex pairs that admit a directed path from the source to the target. Most algorithmic approaches to this problem share a common preprocessing step, in which the input graph is reduced to a tree by repeatedly contracting its cycles. Although this reduction is valid from an algorithmic perspective, the assignment of directions to the edges of the contracted cycles becomes arbitrary and, consequently, the connecting source-target paths may be arbitrarily long.

Order of donor type in pediatric kidney transplant recipients requiring retransplantation.

Background: Living-donor kidney transplantation (KT) is encouraged for children with end-stage renal disease due to superior long-term graft survival compared with deceased-donor KT. Despite this, there has been a steady decrease in the use of living-donor KT for pediatric recipients. Due to their young age at transplantation, most pediatric recipients eventually require retransplantation, and the optimal order of donor type is not clear.

Rates of false flagging due to statistical artifact in CMS evaluations of transplant programs: results of a stochastic simulation.

The recent CMS conditions of participation are based on risk-adjusted models produced by the Scientific Registry for Transplant Recipients (SRTR). The accuracy of these models in identifying poor-performing centers is unknown. In this stochastic simulation study, 1-year mortality outcomes were simulated in virtual transplant centers, and used to flag centers according to the methods used by CMS, evaluating nine overlapping 2.

Living unrelated renal transplantation: a good match for the pediatric candidate?

Background/purpose: Living donor kidney transplantation is encouraged for children with end-stage renal disease given the superior survival of living donor grafts, but pediatric candidates are also given preference for kidneys from younger deceased donors.

Methods: Death-censored graft survival of pediatric kidney-only transplants performed in the U.S.

Addressing geographic disparities in liver transplantation through redistricting.

Severe geographic disparities exist in liver transplantation; for patients with comparable disease severity, 90-day transplant rates range from 18% to 86% and death rates range from 14% to 82% across donation service areas (DSAs). Broader sharing has been proposed to resolve geographic inequity; however, we hypothesized that the efficacy of broader sharing depends on the geographic partitions used. To determine the potential impact of redistricting on geographic disparity in disease severity at transplantation, we combined existing DSAs into novel regions using mathematical redistricting optimization.

Sirolimus based immunosuppression is associated with need for early repeat therapeutic ERCP in liver transplant patients with anastomotic biliary stricture.

Introduction: Sirolimus has inhibitory effects on epithelial healing and cholangiocyte regeneration. In liver transplantation (LT) patients, these effects may be greatest at the biliary anastomosis. We therefore investigated whether sirolimus use is associated with need for early or emergent repeat therapeutic endoscopic retrograde cholangiography (ERC) in LT patients with anastomotic biliary stricture (ABS).

Cancer risk after ABO-incompatible living-donor kidney transplantation.

Background: Recipients of ABO-incompatible (ABOi) living-donor kidney transplants often undergo more intense immunosuppression than their ABO-compatible counterparts. It is unknown if this difference leads to higher cancer risk after transplantation. Single-center studies are too small and lack adequate duration of follow-up to answer this question.

HTK preservative solution is associated with increased biliary complications among patients receiving DCD liver transplants: a single center experience.

Background: This study compares biliary complication rates associated with use of two different preservative solutions, Histidine-Tryptophan-Ketoglutarate (HTK) and University of Wisconsin (UW), utilized in orthotopic liver transplantation (LT) with donations after cardiac death (DCDs).

Material And Methods: Between 1997-2010, we retrospectively studied 35 LTs performed utilizing DCD donors, preserved either with HTK (n=17) or UW(n=18). Biliary complications were defined by the presence of anastomotic strictures, non-anastomotic strictures, and/or biliary leak on endoscopic retrograde cholangiopancreatography.

Optimal codon randomization via mathematical programming.

Codon randomization via degenerate oligonucleotides is a widely used approach for generating protein libraries. We use integer programming methodology to model and solve the problem of computing the minimal mixture of oligonucleotides required to induce an arbitrary target probability over the 20 standard amino acids. We consider both randomization via conventional degenerate oligonucleotides, which incorporate at each position of the randomized codon certain nucleotides in equal probabilities, and randomization via spiked oligonucleotides, which admit arbitrary nucleotide distribution at each of the codon's positions.