Jonathan C. Prather

Effect of Donor Recipient Age Match on Survival after First Deceased Donor Renal Transplantation

Donor-recipient age matching has been proposed as a means of improving overall outcomes in deceased donor renal transplantation. It was hypothesized that donor-recipient age matching would improve patient survival time in younger recipients while not adversely affecting patient survivals in older recipients because they seldom outlive their grafts. By use of data from United Network of Organ Sharing Standard Transplant and Analysis and Research Files 50,320 patients were identified who underwent a first deceased donor renal transplantation between January 1, 1990, and December 31, 1997. Adjusted patient survival and death-with-graft function patient survival were analyzed from the date of transplantation. Patient survival was affected by donor age for all recipient age groups, including recipients older than 55 yr. The effect of donor age on patient survival is greater than that seen with HLA matching. The effect of donor age on patient survival persisted even when censoring recipients in whom grafts failed before death, suggesting that both longevity and quality of graft function are important in patient survival. Donor-recipient age matching is occurring to a limited degree in this population. Donor-recipient age matching would improve survival in younger recipients but would adversely affect survival in older patients by reducing the availability of younger donor kidneys for this group. The issue of donor-recipient age matching needs to be debated among the public and transplantation community so that a logical and just system can be developed.

Factors Associated with Improvement in Deceased Donor Renal Allograft Function in the 1990s

The decade of the 1990s saw an improvement in cadaveric renal graft function and dramatic reduction in the acute rejection (AR) rate. The purpose of this study was to determine whether the reduction in rejection rate was the primary cause of the improvement in graft function seen and whether this improved long-term graft survival. All adult patients who received a cadaver renal transplant between 1991 and 2000 and had graft survival of at least 6 mo and complete data for creatinine at 6 mo, HLA mismatch, delayed graft function, and acute rejection (AR) were identified in the United Network for Organ Sharing database. A total of 40,164 cases that met the inclusion criteria were identified. The mean Modification of Diet in Renal Disease GFR at 6 mo improved from 49.94 ml/min per 1.73 m2 in 1991 to 54.59 ml/min per 1.73 m2 in 2000 (P < 0.001). The improvement in GFR was not gradual but occurred over a 4-yr period between 1994 and 1997, coinciding with the introduction of new immunosuppressive agents mycophenolate mofetil and tacrolimus into maintenance immunosuppression regimens. The improvement was seen in all subgroups of patients, even patients without clinical AR or delayed graft function. The magnitude of improvement in patients without clinical AR was similar to that seen in patients with AR. The drop in clinical AR rate accounted for a minority of the improvement in graft function in the 1990s. Other factors, such as reduced drug toxicity and improved control of subclinical rejection, seem to account for the majority of the improvement. This improvement in graft function at 6 mo did not translate into improved long-term graft survival, however.

Late Steroid Withdrawal and Cardiovascular Events in Kidney Transplant Recipients

Introduction. Cardiovascular events (CVE) are the leading cause of mortality in kidney transplant recipients. The adverse effects of long-term therapy with steroids on cardiovascular risk have motivated increasing interest in steroid withdrawal (SW). The objective of this study was to compare the incidences of CVE and all-cause mortality between patients who had undergone SW at 1 year posttransplant and control patients who continued on steroids. Methods. A cohort of 400 consecutive adult recipients of a kidney transplant between 1993 and 1998 who qualified for late SW was studied. At 1 year posttransplant 188 patients underwent SW, whereas 212 patients continued on steroids. Cox proportional-hazards analysis was used to estimate CVE (cardiac and cerebrovascular events) and all-cause mortality hazard ratios (HR) for patients who had undergone SW versus controls who continued on steroids beyond 1 year. Results. The average follow-up was 61 months. There were 44 (11%) cardiac events, 18 (4.5%) cerebrovascular events, and 41 deaths (10.3%). The composite outcome of CVE and all-cause mortality was reached in 26 (13.8%) subjects who had undergone SW and 50 (23.6%) controls (P=0.013). In adjusted analyses, SW was associated with decreased risk for the composite outcome (HR 0.46, 95% confidence interval [CI] 0.28–0.76), cardiac events (HR 0.48, 95% CI 0.28–0.84), and all-cause mortality (HR 0.27, 95% CI 0.12–0.59). There was no association of SW with the risk for cerebrovascular events (HR 1.76, 95% CI 0.45–7.01). Conclusion. In this retrospective analysis, SW at 1 year posttransplant was associated with decreased risk for future CVE and all-cause mortality.

Long-Term Kidney Regraft Survival From Deceased Donors : Risk Factors and Outcomes in a Single Center

Background. Although survival of kidney regrafts is similar to that of primary grafts, risk factors associated with regraft survival have not been defined clearly. The aim of this study was to investigate risk factors for regraft outcome, including characteristics of the previous and current transplant, and time to retransplant. Methods. In a historical cohort study, 966 primary and 176 repeat deceased donor kidney graft recipients transplanted between January 1, 1990 and December 31, 2004 were studied. Cox regression analysis was used to estimate graft loss hazard ratios (HR) for regrafts versus primary grafts. Adjustments were made for recipient and donor demographics, transplant-related factors (transplant era, panel reactive antibodies, human leukocyte antigens mismatches, immunosuppression, delayed graft function, acute rejection [AR]), previous transplant characteristics (graft survival, graft loss because of AR), and time to retransplant. Results. A total of 508 kidney grafts were lost in the period between January 1990 and May 2007: 427 primary grafts and 81 regrafts. Regraft recipients had a covariate-adjusted 6% increase in graft loss (HR=1.06; P=0.69). Regraft loss was significantly associated with previous graft survival less than or equal to 1 year (HR=2.01; P=0.004), previous graft loss because of AR (HR=2.26; P=0.017) and time to retransplant more than 1 year (HR=2.42; P=0.002). Other significant predictors of regraft loss were diabetes (HR=1.81), donor age more than 50 years (HR=1.86) and delayed graft function after retransplant (HR=1.95). Conclusions. Kidney regrafts seem to have similar long-term outcome as primary grafts. However, additional risk factors significantly associated with regraft survival are previous graft survival, graft loss because of rejection, and time to retransplant.

Use of A2 kidneys for B and O kidney transplant recipients: Report of a series of patients transplanted at a single center spanning a decade

DURING the past several years there has been an increased concern about the discrepancy in waiting times among patients with different ABO blood groups. Specifically, data from the U.S. Scientific Registry indicate that patients with blood group B wait significantly longer than A or O patients for a kidney transplant. Concurrently, there has been increased recognition of the fact that a subtype of ABO A may be a barrier that is permissible to cross in kidney transplantation. Donors who type for A2 represent approximately 20% of all A donors. These individuals’ red blood cells do not agglutinate with the antisera used to type for A1, their cells have a lower amount of A antigen, and they do not express the subtypes A3 and A4 in their kidneys. There is now a significant accumulated experience with using kidneys from these A2 donors for blood group O and B recipients. Use of A2 kidneys for O and B recipients can increase the donor pool for blood group B and O transplant candidates and decrease their waiting times. Moreover, this practice could increase the use of living donors, which can lead to better graft survival versus a non-living donor transplant. The following is a report of our successful experience with the transplantation of A2 kidneys into blood group O and B recipients.