Hospitalized Nephrolithiasis after Renal Transplantation in the United States

The national incidence of and risk factors for hospitalized nephrolithiasis (NEP) in renal transplant (RT) recipients has not been reported. We conducted a historical cohort study of 42 096 RT recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. The 1-year incidence of NEP (ICD-9 codes 592.x) after RT in 1997 was compared to the rate of NEP in the general population using the National Hospital Discharge Survey. Associations with time to hospitalizations for a primary diagnosis of nephrolithiasis were assessed by Cox Regression. NEP was uncommon after RT (104 cases per 100 000 person years in 1997). However, females, but not males, had a statistically significant increased risk of NEP compared to the general population (rate ratio for females, 2.84, 95% confidence interval, 2.35-3.58). Kidney stones were more common than ureteral stones, and percutaneous procedures were more common than ureteroscopy or extracorporeal shock wave lithotripsy (ESWL). The only risk factor identified for NEP was renal failure due to stone disease (only one case). NEP was uncommon after RT, but was still more common than in the general population. We identified differences in the presentation and management of NEP after RT in comparison to the general population.     

Cancer after Kidney Transplantation in the United States

Previous reports of cancer after kidney transplantation have been limited by small numbers of patients in single-center studies and incomplete ascertainment of cases in large registries. We examined rates of malignancies among first-time recipients of deceased or living donor kidney transplantations in 1995-2001 (n = 35 765) using Medicare billing claims. For most common tumors, e.g. colon, lung, prostate, stomach, esophagus, pancreas, ovary and breast, cancer rates were roughly twofold higher after kidney transplantation compared with the general population. Melanoma, leukemia, hepatobiliary tumors, cervical and vulvovaginal tumors were each approximately fivefold more common. Testicular and bladder cancers were increased approximately threefold, while kidney cancer was approximately 15-fold more common. Kaposi's sarcoma, non-Hodgkin's lymphomas, and nonmelanoma skin cancers were more than 20-fold increased than in the general population. Compared with patients on the waiting list, several tumors were more common after transplantation (p < 0.01): nonmelanoma skin cancers (2.6-fold), melanoma (2.2-fold), Kaposi's sarcoma (9.0-fold), non-Hodgkin's lymphoma (3.3-fold), cancer of the mouth (2.2-fold), and cancer of the kidney (39% higher). The rates for most malignancies are higher after kidney transplantation compared with the general population. Cancer should continue to be a major focus of prevention in kidney transplantation.     

Thrombotic microangiopathy in United States long-term dialysis patients.

BACKGROUND: The incidence, risk factors, recurrence rates and prognosis of thrombotic microangiopathy (TMA) among long-term dialysis patients in the United States have not been previously described in a national population. METHODS: 272 024 Medicare primary patients in the United States Renal Data System (USRDS) initiated on end-stage renal disease (ESRD) therapy between 1 April 1995 and 31 December 1999 with Medicare as primary payer were analysed in a retrospective cohort study of USRDS of TMA. Cox regression was used to calculate adjusted hazard ratios (AHR) for risk of TMA and risk of death after TMA. RESULTS: The incidence of TMA in the first year of dialysis was 0.5% overall. Among patients with renal failure due to haemolytic uraemic syndrome (HUS), the incidence of TMA was highest in the first year of dialysis (HUS, 11.3% first year, 4.5% per year thereafter), while among patients without HUS the incidence of TMA was much lower and more constant over time (0.3% per year). In Cox regression analysis, independent risk factors for TMA were renal failure due to HUS (adjusted hazard ratio (AHR) 179, 95% CI 95-338), paediatric age (相似文献   

Racial and Ethnic Differences in Pediatric Access to Preemptive Kidney Transplantation in the United States

Preemptive kidney transplantation is the optimal treatment for pediatric end stage renal disease patients to avoid increased morbidity and mortality associated with dialysis. It is unknown how race/ethnicity and poverty influence preemptive transplant access in pediatric. We examined the incidence of living donor or deceased donor preemptive transplantation among all black, white, and Hispanic children (<18 years) in the United States Renal Data System from 2000 to 2009. Adjusted risk ratios for preemptive transplant were calculated using multivariable‐adjusted models and examined across health insurance and neighborhood poverty levels. Among 8,053 patients, 1117 (13.9%) received a preemptive transplant (66.9% from LD, 33.1% from DD). In multivariable analyses, there were significant racial/ethnic disparities in access to LD preemptive transplant where blacks were 66% (RR = 0.34; 95% CI: 0.28–0.43) and Hispanics 52% (RR = 0.48; 95% CI: 0.35–0.67) less likely to receive a LD preemptive transplant versus whites. Blacks were 22% less likely to receive a DD preemptive transplant versus whites (RR = 0.78, 95% CI: 0.57–1.05), although results were not statistically significant. Future efforts to promote equity in preemptive transplant should address the critical issues of improving access to pre‐ESRD nephrology care and overcoming barriers in living donation, including obstacles partially driven by poverty.     

The Incidence and Costs of Sepsis and Pneumonia Before and After Renal Transplantation in the United States

We compared the graft survival and accumulative costs associated with sepsis and pneumonia pre- and post-transplantation. We analyzed 44 916 first kidney transplants from 1995 to 2001 USRDS where Medicare was the primary payer. We drew five cohorts for each disease from the baseline population: patients who had a disease onset in the first or second years pre-transplantation (cohorts 1 and 2) or post-transplantation (cohorts 3 and 4) and patients who were disease-free (cohort 5). For each cohort, we calculated graft survival and average accumulated Medicare payments (AAMPs) for the two pre- and post-transplantation years. Graft survival: new-onset sepsis and pneumonia both significantly (p <0.01) lowered graft survival during the year of onset. AAMPs: the AAMPs incurred by sepsis- (pneumonia-) free patients during the first and second years post-transplantation were dollar 50,000 and 13,000 (dollar 51,100 and 13,500), respectively. Patients with a sepsis (pneumonia) onset post-transplantation cost on average dollar 48,400 (dollar 38,400) extra (p<0.01). Episodes of sepsis and pneumonia have a strong and independent impact on graft survival and costs.     

Hospitalizations for Total Hip Arthroplasty after Renal Transplantation in the United States

The national incidence of and factors associated with total hip arthroplasty in renal transplant recipients has not been reported. We conducted an historical cohort study of 42096 renal transplant recipients in the United States between 1 July 1994 and 30 June 1998. Primary outcomes were associations with hospitalizations for a primary discharge code of total hip arthroplasty (ICD9 procedure code 81.51x) within 3 years after renal transplant using Cox regression. Renal transplant recipients had a cumulative incidence of total hip arthroplasty of 5.1 episodes/1000 person-years, which is 5-8 times higher than reported in the general population. Avascular necrosis of the hip was the most frequent primary diagnosis associated with total hip arthroplasty in this population (72% of cases). Repeat surgeries were performed in 27% of patients with avascular necrosis, vs. 15% with other diagnoses. Total hip arthroplasty was more frequent in transplant recipients who were older, African American, or who experienced allograft rejection. Mortality after total hip arthroplasty was 0.21% at 30 days and 15% at 3 years, similar to the mortality of all transplant recipients. The most common indication for total hip arthroplasty after renal transplant is avascular necrosis of the hip, in contrast to the general population. Although repeat surgeries are common, total hip arthroplasty is well tolerated and is not associated with increased mortality in this population.     

HIV-associated nephropathy and end-stage renal disease in children in the United States

Single-center studies have reported that HIV-associated nephropathy (HIVAN) can occur in children and may have a clinical course and prognosis similar to that of adults. However, the prevalence and survival has not been reported for a national sample of children with HIVAN and end-stage renal disease (ESRD) on dialysis in the United States. We utilized the United States Renal Data System (USRDS) database to determine the prevalence, demographic information, and survival of children with HIVAN and ESRD in the United States. The Kaplan-Meier method was used to estimate survival of children with HIVAN and the log-rank test was used to compare their survival with children with focal segmental glomerulosclerosis (FSGS) and adults with HIVAN. Cox regression analysis was used to model adjusted hazard ratios (AHR) with HIVAN as a cause of ESRD and its impact on mortality during the study period, adjusted for potential confounders. Of the 7,732 patients identified with HIVAN, only 60 were younger than 21 years and were classified as children; 50% were males and the majority (88.3%) was black. The cumulative percentage survival of children with HIVAN at 12, 24, and 36 months was better than adults with HIVAN (76%, 62%, and 54% vs. 60%, 43%, and 34%). Survival of children with HIVAN who started dialysis after 1996 was significantly better than those who started dialysis in or before 1996 (log rank P value <0.043). However, the major factor associated with better survival on Cox proportional hazard analysis was female gender (male vs. female AHR 2.85, 95% confidence interval 1.04–6.73). We conclude that only a small number of children with HIVAN and ESRD have received dialysis in the United States. The prognosis of these children is better than that of adults with HIVAN and among children with HIVAN females have better survival than males.The data reported have been supplied by the United States Renal Data System (USRDS). The interpretation and reporting of these data are the responsibility of the author (s) and in no way should be seen as an official policy or interpretation of the United States government     

Mortality After Kidney Transplantation: A Comparison Between the United States and Canada

There is a paucity of comparative studies on country-specific outcomes in kidney transplantation. We compared post-transplant mortality among primary, adult, solitary kidney transplant recipients (KTR) from the United States (n = 70 708) and Canada (n = 5773), between January 1, 1991 and December 31, 1998, using data from the Scientific Registry of Transplant Recipients and the Canadian Organ Replacement Register. Multivariable Cox regression revealed higher adjusted post-transplant mortality among U.S. (vs. Canadian) KTR (HR = 1.35 [95% CI 1.24, 1.47; p < 0.005]). Mortality risk in the first post-transplant year was similar in both countries but higher in the United States beyond the first year (HR = 1.49-1.53; p < 0.005). There was no difference in mortality among patients transplanted within 1 year of starting dialysis, but mortality was increased in U.S. (vs. Canadian) patients after 1-2 and 4+ years on dialysis (HR = 1.36-1.66; p < 0.005). Greater mortality was also seen in U.S. patients with diabetes mellitus and/or graft failure. In conclusion, there are considerable differences in the survival of KTR in the United States and Canada. A detailed examination of factors contributing to this variation may yield important insights into improving outcomes for all KTR.     

Etiology of sustained hypertension in children in the Southwestern United States

We reviewed the records of 132 children with persistent hypertension who were evaluated by our pediatric nephrology services between 1987 and 1991. Eightynine (67%) of these children were found to have renal or renovascular disease, 30 (23%) had primary hypertension and 13 (10%) had a non-renal cause for their hypertension. Glomerulonephritis (n=37) and reflux nephropathy (n=26) were the most frequent renal disorders identified. Renal artery thrombosis was the most common cause of hypertension in the neonatal period (in 6 of 12 neonates, 50%) whereas cystic kidney disease was the most common cause of hypertension in the 1st year of life (in 9 of 30 infants, 30%). The prevalence of primary hypertension increased with age; this diagnosis was made in 16 of 46 (35%) hypertensive patients between 12 and 18 years of age and, more surprisingly, in 8 of 27 (30%) children between 7 and 11 years of age. These data confirm that secondary hypertension is the most common cause of hypertension in children but suggest that primary hypertension is more prevalent than previously recognized in patients between 7 and 18 years of age.     

Current practice patterns in the surgical management of renal cancer in the United States

Over the last two decades, there has been a rising incidence of renal tumors, particularly, small renal masses (<4 cm) resulting in a downward size and stage migration. This has brought about a paradigm shift in the management of newly diagnosed renal masses, such that nephron-sparing surgery, minimally invasive techniques, and active surveillance are frequently considered preferable to the historical gold standard of open radical nephrectomy. Population-based cohort studies indicate, however, that the widespread adoption of these techniques has been relatively slow and incomplete leading to significant disparities in the delivery of care throughout the country. Further investigation is required to determine the barriers to diffusion of new techniques and technology as well as to ensure equal access to quality care in the United States.     

Repeat Organ Transplantation in the United States, 1996–2005

The prospect of graft loss is a problem faced by all transplant recipients, and retransplantation is often an option when loss occurs. To assess current trends in retransplantation, we analyzed data for retransplant candidates and recipients over the last 10 years, as well as current outcomes. During 2005, retransplant candidates represented 13.5%, 7.9%, 4.1% and 5.5% of all newly registered kidney, liver, heart and lung candidates, respectively. At the end of 2005, candidates for retransplantation accounted for 15.3% of kidney transplant candidates, and lower proportions of liver (5.1%), heart (5.3%) and lung (3.3%) candidates. Retransplants represented 12.4% of kidney, 9.0% of liver, 4.7% of heart and 5.3% of lung transplants performed in 2005. The absolute number of retransplants has grown most notably in kidney transplantation, increasing 40% over the last 10 years; the relative growth of retransplantation was most marked in heart and lung transplantation, increasing 66% and 217%, respectively. The growth of liver retransplantation was only 11%. Unadjusted graft survival remains significantly lower after retransplantation in the most recent cohorts analyzed. Even with careful case mix adjustments, the risk of graft failure following retransplantation is significantly higher than that observed for primary transplants.     

Health Insurance and the Use of Peritoneal Dialysis in the United States

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Parathyroidectomy and Cinacalcet Use in Medicare-Insured Kidney Transplant Recipients

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Lung Transplantation in the United States, 1998–2007

This article highlights trends and changes in lung and heart-lung transplantation in the United States from 1998 to 2007. The most significant change over the last decade was implementation of the Lung Allocation Score (LAS) allocation system in May 2005. Subsequently, the number of active wait-listed lung candidates declined 54% from pre-LAS (2004) levels to the end of 2007; there was also a reduction in median waiting time, from 792 days in 2004 to 141 days in 2007. The number of lung transplants performed yearly increased through the decade to a peak of 1 465 in 2007; the greatest single year increase occurred in 2005. Despite candidates with increasingly higher LAS scores being transplanted in the LAS era, recipient death rates have remained relatively stable since 2003 and better than in previous years. Idiopathic pulmonary fibrosis became the most common diagnosis group to receive a lung transplant in 2007 while emphysema was the most common diagnosis in previous years. The number of retransplants and transplants in those aged ≥65 performed yearly have increased significantly since 1998, up 295% and 643%, respectively. A decreasing percentage of lung transplant recipients are children (3.5% in 2007, n = 51). With LAS refinement ongoing, monitoring of future impact is warranted.     

The Current State of Liver Transplantation in the United States

This article is a review of the salient points and a future prospective based on the 2014 Organ Procurement and Transplantation Network (OPTN)/Scientific Registry of Transplant Recipients (SRTR) liver donation and transplantation data report recently published by the American Journal of Transplantation. Emphasis of our commentary and interpretation is placed on data relating to waitlist dynamics, organ utilization rates, the impact of recent advances in the treatment of hepatitis C, and the increases in end‐stage renal disease among liver transplant candidates. Finally, we share our vision on potential areas of innovation that are likely to significantly improve the field of liver transplantation in the near future.     

Trends in Cardiac Surgery-Associated Acute Renal Failure in the United States: A Disproportionate Increase after Heart Transplantation

Acute renal failure (ARF) is common after cardiac surgery and more frequent after complex cardiac surgery. While the incidence of ARF is increasing after coronary artery bypass graft (CABG) surgery, trends in other forms of cardiac surgery remain unclear. We investigated the trend of ARF in various cardiac procedures and compared patterns using CABG surgery as a reference group. The study population consisted of discharges from the Nationwide Inpatient Sample from 1988 to 2003, grouped according to surgery as: CABG, CABG with mitral valve, CABG with other valve, valve alone, and heart transplant. Standard diagnostic codes were used to identify ARF among discharges. Multivariable regression was used to determine trends in ARF among various procedures with CABG as a reference group. The incidence of ARF increased in all five groups (p < 0.001) over the 16-year period. The ARF incidence was highest in the heart transplant group (17%). Compared to the CABG population, patients following heart transplantation developed ARF at higher rates during the study period. In contrast, while ARF increased over time in other groups, the rates of rise were slower than in CABG patients. Among heart surgery procedures, ARF incidence is highest in heart transplantation. The incidence of ARF is also increasing at a faster rate in this group of patients in contrast to other procedure groups when compared to CABG surgery. The disproportionate increase in ARF burden after heart transplantation is a concern due to its strong association with chronic kidney disease and mortality.     

ABO‐Nonidentical Liver Transplantation in the United States

Under the United Network for Organ Sharing (UNOS) policy, deceased donor livers may be offered to ABO‐nonidentical candidates at each given Model for End‐Stage Liver Disease (MELD) score and to blood type B candidates at MELD ≥30. To evaluate ABO‐nonidentical liver transplantation (LT) in the United States, we examined all adult LT non–status 1 candidates, recipients and deceased liver donors from 2013 to 2015. There were 34 920 LT candidates (47% type O, 38% type A, 12% type B, 3% type AB) and 10 479 deceased liver donors (47% type O, 38% type A, 12% type B, 3% type AB). ABO‐nonidentical LT occurred in 2%, 3%, 20% and 36% of types O, A, B and AB recipients, respectively, which led to a net liver loss of 6% for type O and 2% for type A recipients but a net liver gain of 14% for type B and 55% for type AB recipients. The LT MELD scores of ABO‐identical versus ‐nonidentical recipients were 29 versus 34 for type O, 29 versus 19 for type A, 25 versus 38 for type B, and 22 versus 28 for type AB (p < 0.01). ABO‐nonidentical LT increased liver supply for candidates with blood types B and AB but decreased supply for type O and A candidates. We urge refinement of UNOS policy surrounding ABO‐nonidentical LT.