Renal allograft survival in patients with oxalosis.

BACKGROUND: Primary hyperoxaluria is a rare autosomal recessive metabolic disease that often progresses to end-stage renal disease (ESRD). Liver transplantation is curative for patients with the alanine: glyoxylate aminotransferase deficiency. For oxalosis patients with minor enzyme deficiencies, renal transplantation may be the therapy of choice although concern exists about recurrence of oxalosis in the transplanted kidney. To date, previous data has been conflicting with most reports indicating poor renal allograft survival for oxalosis patients who receive a renal transplant alone. To determine whether graft survival in renal transplant recipients with oxalosis is similar to other transplant recipients with other forms of ESRD, we analyzed the United States Renal Data System (USRDS) registry comparing death-censored graft survival for transplant recipients with oxalosis to a reference group with ESRD secondary to glomerulonephritis (GN). METHODS: Using the USRDS and the U.S. Scientific Renal Transplant Registry data, we found 190 adult renal transplant recipients from 1988 to 1998 who had oxalosis as their primary diagnosis for their ESRD. Among the patients with oxalosis, 56 patients had a liver transplant followed by a kidney transplant (LKTx) and 134 patients had a kidney transplant alone (KTA). A Cox proportional hazard model was used to estimate patient survival and death-censored graft survival for patients with oxalosis who received a LKTx or a KTA. Unadjusted death-censored graft survival for oxalosis patients with a cadaveric or living-donor KTA or with a LKTx was obtained from Kaplan-Meier analysis. Recipients of solitary kidney transplants with GN served as the reference group. RESULTS: Oxalosis patients receiving a KTA had a significantly worse adjusted death-censored graft survival (47.9%) compared with patients with GN (61%) at 8 years posttransplantation (P <0.001). In contrast, oxalosis patients who received a LKTx had a significantly higher death-censored graft survival (76%) compared with oxalosis patients who received a KTA (47.9%, P<0.001) and had a trend toward better death-censored graft survival compared with patients with GN (P =0.05). In addition, oxalosis patients who received a living-donor KTA had significantly worse death-censored graft survival compared with oxalosis patients who received a LKTx (22% vs. 64%, P<0.01). Patient survival for oxalosis recipients with a KTA or a LKTx was not significantly different. CONCLUSIONS: Patients with oxalosis who receive a LKTx have superior death-censored graft survival compared with oxalosis patients who receive a cadaveric or living-donor KTA and trended toward better graft survival compared with GN patients.

Association of antibody induction with short- and long-term cause-specific mortality in renal transplant recipients.

A total of 73,707 primary renal transplants reported to the USRDS between 1988 and 1997 were examined to investigate the cause-specific risk for patient death associated with anti-lymphocyte antibody induction therapy (ABI). Cox proportional hazard models were used to estimate the relative risk of the use of ABI and patient death. All Cox models were corrected for potential confounding variables, such as age, gender, race, HLA mismatch, panel reactive antibody, delayed graft function, cold ischemia time, time since start of dialysis, etiology of end-stage renal disease, cytomegalovirus risk group, donor source (living or cadaveric), era effect, and immunosuppressive therapy. Primary study end points were patient death with functioning graft (DWFG) and overall patient death, including death after graft loss. Early patient death (deaths within the first 6 mo after renal transplantation) and late death (deaths after 6 mo post-renal transplantation) were investigated separately. Additionally, specific causes of death were investigated. ABI was associated with a significant risk for late death after renal transplantation (relative risk [RR] = 1.1; P < 0.001) but not for DWFG (RR = 0.94; P = 0.10). ABI conferred the highest RR for late malignancy-related death (RR = 1.35; P < 0.001). ABI was significantly associated with early deaths due to infection and cardiovascular causes (RR = 1.32 [P < 0.001] and RR = 1.27 [P < 0.001], respectively). Kaplan Meier plots confirmed that the risk of ABI for patient death secondary to infectious complications was increased predominately early after transplantation as opposed to late for malignancy-related death. ABI was associated with a significant relative risk for patient death secondary to cardiovascular causes and infectious complications early in the posttransplant period. In addition, ABI was associated with a significant risk for long-term malignancy-related death. The risk of ABI should be taken in context with potential benefits of this therapy.

The impact of body mass index on renal transplant outcomes: a significant independent risk factor for graft failure and patient death.

INTRODUCTION: Renal transplant recipients with elevated body mass index (BMI) have been shown to have inferior patient survival as compared to patients with lower BMI. However, previous studies could not establish a link between increased BMI and decreased death censored graft survival. Obesity in nontransplant patients has been associated with hypertension, hyperlipidemia, type II diabetes, proteinuria and glomerulopathy. Given this evidence it is possible that renal transplant recipients with an elevated BMI may have worse long term graft survival. To investigate this hypothesis we retrospectively analyzed 51,927 primary, adult renal transplants registered in the USRDS. METHODS: BMI at date of transplant was calculated for all patients using BMI=body weight (in kg)=.stature (height, in meters) squared. BMI values were further categorized into 11 categories: below 18, from 18 to 36 at 2 unit increments, and above 36 kg/m2. Primary study end points were graft and patient survival. Secondary study end points were death censored graft survival, chronic allograft failure, delayed graft function, and acute rejection (AR). Cox proportional hazard and logistic regression models investigated the link between categorized BMI and the study end points correcting for potential confounding variables. RESULTS: BMI showed a very strong association with outcomes after renal transplantation. The extremes of very high and very low BMI were associated with significantly worse patient and graft survival. The same was true for death censored graft survival and chronic allograft failure. Elevated BMI was also associated with an increased risk for delayed graft function while lower BMI was significantly protective. Acute rejection did not show any significant association with BMI. CONCLUSIONS: BMI has a very strong association with outcomes after renal transplantation independent of most of the known risk factors for patient and graft survival. The extremes of very high and very low BMI before renal transplantation are important risk factors for patient and graft survival. It is important to note that elevated BMI was significantly associated with worse graft survival independent of patient survival. Whether prospective weight adjustment before renal transplantation can favorably affect posttransplant risk needs to be assessed by further studies.

Survival improvement among patients with end-stage renal disease: trends over time for transplant recipients and wait-listed patients.

Both transplant and dialysis outcomes have improved over recent years. In addition, transplantation has been shown to confer a survival benefit over maintenance dialysis. The study presented here addresses the question of whether the survival benefit of transplantation over maintenance dialysis has changed in the most recent eras. This study was based on data collected by the United States Renal Transplant Scientific Registry and the United States Renal Data System. The study sample consisted of 104,000 patients placed on the renal transplant waiting list between 1988 and 1996, of which 73,707 subsequently received renal transplants. The annualized adjusted mortality rates per 1000 patient-years were calculated by calendar year of placement on the renal transplant waiting list and for kidney transplant recipients. The resulting data were plotted, and linear curve fitting was used to estimate the slope of the change of the adjusted mortality rates by year during the period studied, 1988 to 1996. Overall annual adjusted death rates in the wait-listed patients and transplant recipients per 1000 patient-years decreased for both groups throughout the study period. From 1989 to 1996, the relative risk (RR) for patient death had decreased by 30% for transplant recipients and 23% for wait-listed patients (RR = 0.70 and 0.77; P < 0.0001 each). Slope analysis of the cause-specific mortality rates for cardiovascular disease and infection showed nearly equivalent, linear decreases for both groups. Mortality rates have improved overall and by categories of major cause of death for both renal transplant recipients and patients on the renal transplant waiting list. These favorable trends most likely represent equal advances in transplantation, dialysis, and general medical care.