Similar risk profiles for post-transplant renal dysfunction and long-term graft failure: UNOS/OPTN database analysis

BACKGROUND: Renal dysfunction measured by serum creatinine (>1.5 mg/dL) at 1 year post-transplant correlates with long-term kidney graft survival. The purpose of this study was to compare the risk factors for elevated serum creatinine (SCr) >1.5 mg/dL at 1 year post-transplantation, and for long-term graft failure. METHODS: Between 1988 and 1999, 117,501 adult kidney transplants were reported to Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS). Of these, 96,091 were functioning at 1 year and SCr was available on 85,135 transplants. Donor and recipient demographics (age, sex, and race), transplant [living vs. cadaveric, previous transplantation, panel reactive antibody (PRA), human leukoocyte antigen (HLA) mismatch, cold ischemic time (CIT) and post-transplant delayed graft function (DGF), use of azathioprone vs. mycophenolate mofetil (MMF), cyclosporine A (CsA) vs. tacrolimus (Tac)], induction antibody, acute rejection within 1 year variables were used in the logistic regression model to estimate odds ratio (OR) for elevated 1 year serum creatinine (SCr). A Cox proportional hazard model was used to estimate the relative risk (RR) for long-term kidney graft failure with and without censoring for death with a functioning graft. RESULTS: Five-year actuarial graft survival for living donor transplant with SCr >1.5 and 1.5 mg/dL) declined from 54.5% in 1988 to 42.3% in 1999. There was a strong concordance between the key variables, such as cadaveric transplant, increasing CIT, HLA mismatch, DGF, and acute rejection, recipient race (black), younger age, and nondiabetics status; and donor race (black) and older age for elevated SCr and long-term graft failure. CONCLUSION: Donor (age), race (black), recipient race (black), immunologic variables (HLA mismatch, DGF, acute rejection) were identified as important risk factors for elevated SCr at 1 year post-transplantation and long-term graft failure. Elevated SCr should be used as a short-term marker for predicting long-term transplant survival.     

Rapid Resolution of Proteinuria of Native Kidney Origin Following Live Donor Renal Transplantation

To assess the contribution of the protein content of urine from the native kidneys to post-transplant proteinuria, we prospectively studied 14 live donor transplant recipients with a pre-transplant random urine protein to creatinine ratio (UPr:Cr) >0.5. Seven patients received preemptive transplants, and seven patients were on dialysis pre-transplant (with residual urine output). Resolution of proteinuria was defined as UPr:Cr < 0.2. Immunosuppression consisted of tacrolimus, mycophenolate mofetil and corticosteroids. Anti-hypertensive drugs that might reduce proteinuria were avoided during the study. The serum creatinine was 8.7 +/- 0.7 mg/dL pre-transplant, and the nadir post-transplant serum creatinine was 1.4 +/- 0.1 mg/dL. The pre-transplant UPr:Cr ranged between 0.5 and 9.2 (mean = 2.9 +/- 0.6). The UPr:Cr decreased to <0.2 in all 14 patients at a mean of 4.5 weeks post-transplant (range 1-10 weeks). In conclusion, in live donor renal transplant recipients with immediate graft function, proteinuria of native kidney origin resolves in the early post-transplant period. After the immediate post-transplant period, proteinuria cannot be attributed to the native kidneys, and work up for proteinuria should focus on the allograft.     

One-year posttransplant renal function is a strong predictor of long-term kidney function: results from the Neoral-MOST Observational Study

BACKGROUND: Peritransplant risk factors influence short-term and long-term graft survival, and 1-year serum creatinine is known to predict long-term graft survival. To examine interrelationships between risk factors, renal function at 1 year, and long-term graft function in patients maintained on cyclosporine, we analyzed data collected from 10,692 de novo or maintenance renal transplant recipients in an ongoing international, prospective, observational study--Neoral-MOST (Multinational Observational Study in renal Transplantation). The effect of donor age, delayed graft function, acute rejection, donor type, panel-reactive antibodies, and previous graft on 1- and 5-year renal function and their relationship to 1-year serum creatinine was assessed. RESULTS: Donor age, delayed graft function, acute rejection, and donor type significantly increased the risk for serum creatinine > 130 micromol/L at 1 year posttransplant, and 1-year serum creatinine was the strongest predictor of 5-year renal function. After adjustment for 1-year serum creatinine, an ongoing influence was observed for donor age, donor type, and previous graft. Delayed graft function and acute rejection had a significant effect on serum creatinine at year 1 but no additional impact on long-term graft function. CONCLUSIONS: Serum creatinine at 1 year is influenced by risk factors known to affect overall graft survival and is predictive of 5-year renal graft function. The effects of delayed graft function and acute rejection appear to be limited to their influence on serum creatinine at 1 year, whereas donor type and previous graft predominantly affect later stages of graft life.     

Effect of acute rejection episode on occurrence of chronic rejection after kidney transplantation

Chronic rejection is the most prevalent cause of renal transplant failure in the late post-transplant period. The clinical significance of acute rejection episodes on occurrence of chronic rejection is controversial. We analyzed 503 cases of the first renal transplantation maintained by calcinurine inhibitor for the correlation of acute rejection and clinical chronic rejection. The later the first episode of acute rejection occurred, the shorter was the half-life of graft. The acute rejection occurring within 3 post-transplant months worsens long-term graft survival if the peak creatinine level exceeds 2 mg/dl. Multivariate analysis by the Cox proportional hazard model for factors affecting cadaver graft loss by chronic rejection, revealed that the risk factor of acute early rejection was lower than those of donor age and post-transplant hypertension.     

Change in serum creatinine levels between 6 and 12 months and kidney graft survival: influence of proteinuria

Renal function within the first year after transplantation has been shown to be an important parameter influencing long-term survival. In this study, we examined the relationship between long-term outcome in 365 renal transplants and renal function in the first year, expressed as serum creatinine (SCr) level at 6 months and at 1 year as well as namely deltaCr, the change in SCr between 6 months and 1 year. In addition, we examined the influence of the presence of proteinuria as a predictive factor for a worse evolution. Graft survival was worse among patients with higher deltaCr, especially among those who developed proteinuria. In a Cox regression analysis of long-term graft survival, both deltaCr and proteinuria were important predictors of half-life. The risk of graft loss when deltaCr >0.3 was 2.65 (1.8-3.8; P < .000), whereas the risk increased to 5.67 (3.3-9.4; P < .00) when proteinuria was present. In conclusion, deltaCr values predict long-term graft survival. Patients who developed proteinuria were at higher risk for graft loss compared with those without proteinuria. By using a combination of SCr and deltaCr with proteinuria, it is possible to identify a subset of transplant recipients with a predictably shortened half-life.     

Dominant effect of histocompatibility on ten-year kidney transplant survival

Using actuarial methods, factors influencing long-term graft survival were examined in 33,594 recent (since 1974) kidney transplants reported to the University of California, Los Angeles, Transplant Registry. One- and 10-year graft-survival rates as well as late (from 3 through 10 years) graft-loss rates (half-lives) were determined. The donor-recipient relationship had the greatest influence on long-term graft survival. Transplants between HLA-identical siblings had graft-survival rates of 89% at 1 year and 68% at 10 years, compared with 76% and 43% for parental donors, and 58% and 26% for cadaver donor transplants, respectively. These differences were also evident from the graft half-lives, which were 22 years for HLA-identical sibling, 12 years for parental, and 8 years for cadaver donor allografts. In cadaver donor transplants, matching for HLA-A,B antigens had the greatest influence on long-term graft survival, with a 15% 10-year graft survival (39% vs. 24%) and 7-year half-life (14 vs. 7 years) advantage seen with the best (zero HLA-A,B mismatches) compared with the worst (4 HLA-A,B) cases, respectively. Some of the factors studied, such as transplant number and pretransplant transfusions, tended to influence the short- rather than long-term graft-survival rates. Others, including HLA-A,B matching, early graft function and the recipient's original disease, influenced both early and late graft survival. Over all, histocompatibility between donor and recipient had by far the greatest influence on the long-term success of renal allografts.     

Risk factors for slow graft function after kidney transplants: a multivariate analysis

BACKGROUND: We previously defined an intermediate group of cadaver kidney transplant recipients who do not have immediate graft function (IGF), but do not have sufficient graft dysfunction to be classified as having delayed graft function (DGF). We showed that this group with slow graft function (SGF) had an increased risk of rejection and inferior long-term results vs. recipients with IGF. The aim of our current study was to determine risk factors for SGF, which have not been well defined (in contrast to risk factors for DGF). METHODS: Between January 1, 1984 and September 30, 1999, we performed 896 adult cadaver kidney transplants at the University of Minnesota. Recipients were analysed in three groups based on initial graft function: IGF [creatinine (Cr) < 3 mg/dL by post-operative day (POD) no. 5], SGF (Cr > 3 mg/dL on POD no. 5, but no need for dialysis), and DGF (need for dialysis in the first week post-transplant). A multivariate analysis looked specifically at risk factors for SGF, as compared with risk factors for DGF. Outcomes with regard to graft survival and acute rejection (AR) rates were determined for the three groups. RESULTS: Of the 896 recipients, 425 had IGF, 238 had SGF, and 233 had DGF. A multivariate analysis of risk factors for SGF showed donor age >50 yr (RR=3.3, p=0.0001) and kidney preservation time >24 h (RR=1.6, p=0.01) to be the most significant risk factors. A multivariate analysis of risk factors for DGF showed similar findings, although high panel-reactive antibodies (PRA) and donor Cr >1.7 mg/dL were also significant risk factors for DGF. Initial function of the graft significantly influenced the subsequent risk of AR: at 12 months post-transplant, the incidence of AR was 28% for those with IGF, 38% for those with SGF, and 44% for those with DGF (p=0.04 for SGF vs. DGF). Initial graft function also significantly influenced graft survival: the 5-yr death-censored graft survival rate was 89% for recipients with IGF, 72% for those with SGF, and 67% for those with DGF (p=0.01 for IGF vs. SGF; p=0.03 for SGF vs. DGF). CONCLUSIONS: SGF represents part of the spectrum of graft injury and post-transplant graft dysfunction. Risk factors for SGF are similar to those seen for DGF. Even mild to moderate graft dysfunction post-transplant can have a negative impact on long-term graft survival.     

Evolution of the renal function is a better predictor of long-term survival than serum creatinine

BACKGROUND: In recent years acute rejection has decreased to 10% to 20%. Therefore it is necessary to look for new endpoints in renal transplantation. Serum creatinine and changes in creatinine have been reported to be powerful predictors of long-term kidney transplant survival. Chronic renal allograft nephropathy is the primary cause of long-term graft failure but may appear at any stage in the evolution. METHODS: Data from 315 patients receiving cadaver donor renal transplants between February 1987 and March 2001 that functioned for 1 year were examined for the influence of demographic characteristics and transplant variables. Creatinine clearance was estimated using the Cockroft-Gault formula. Survival was assessed with the actuarial method. The multivariate analyses were performed using Cox proportional hazard models. RESULTS: The 10-year graft survival showed a relative risk of 2.5 in the univariate analysis when there was more than 10% decrease in renal function at 3 months compared with nadir values. When the decrease was more than 25% of creatinine clearance at the third month, during the evolution and serum creatinine at 3 months introduced in the multivariate model, the latter was not significant, while the other variables had a RR of 4.4 and 10, respectively. CONCLUSION: The evolution of renal function at 3 months and throughout the evolution were better predictors of graft failure than an isolated serum creatinine value.     

Correlation Between MLC Stimulation and Graft Survival in Living Related and Cadaver Transplants

"Multiple MLC's" (parallel tests in recipient, donor and globulin-poor plasma) were performed in 211 consecutive transplant donor-recipient pairs(2) The two-way MLC's were performed on patients' lymphocytes before immunosuppression. All grafts regarded as "successful" were at risk for at least six months. Patients with a low MLC (Stimulation Index less than 8 times controls) usually had successful grafts (graft survival was 83% in related transplants and 76% in cadaver transplants). Patients with high MLC's had poor graft survival (0% graft survival in related transplants and 32% in cadaver transplants). An adjusted graft survival was calculated to exclude patients who died with normal renal function (serum creatinine less than 2 mg%). The adjusted graft survival was 91% for living related transplants and 88% for cadaver transplants. Falsely low MLC's occurred when the recipient's plasma contained low-titer cytotoxic antibodies. In 15 recipients of cadaver kidneys, the MLC in recipient plasma was significantly lower than MLC's in donor or globulin-poor plasma. Since the MLC when using cadaver donors was necessarily retrospective, the results were not known pre-transplant and all 15 grafts were rejected. In living related pairs, however, we were able to screen for such antibody activity and could avoid humoral presensitization and cellular compatibility.     

Renal transplantation from elderly living donors

A worldwide shortage of cadaveric donors has led to the increased utilization of elderly living donors, with controversial results. In an attempt to assess the effect of donor age on graft survival and subsequent renal function, we analyzed our clinical results in 276 consecutive recipients of living related renal transplants spanning both the cyclosporine and the azathioprine eras, of whom a total of 44 recipients received kidneys from donors over 55 years old. All recipients were otherwise similar in age, race, haplotype mismatch, number of retransplants, and number of pretransplant transfusions, apart from an increased number of diabetics among the CsA-treated recipients of elderly kidneys (38% vs. 14%). The cumulative patient and graft survival rates at 1 and 5 years were independent of donor age whether CsA or AZA was utilized. Nor was the incidence of rejection or infection significantly different in the older donor group when compared with the younger cohort. Short-term and intermediate-term renal function, as assessed by serum creatinine, was however poorer but stable in the older donor group when compared with the younger one. The mean serum creatinine levels at 1 year in the CsA- and AZA-treated recipients of kidneys from older donors were 2.4 and 2.0 mg/dl, respectively, compared with 1.6 and 1.4 mg/dl, respectively, when the donor age was less than 55 years (P less than 0.001). Since renal function at the end of the first posttransplant year is considered a determinant of long-term graft survival, this is a cause for concern, but in view of the universal shortage of organs and the negligible morbidity to donors, renal transplantation from elderly living donors remains an acceptable practice.     

Outcome of renal transplantation in children less than two years of age.

Twenty-two renal transplants were performed in 21 children less than two years of age at Children's Hospital. Fourteen were from living related donors and eight were from cadaveric donors. The five year patient and graft survivals of these recipients were compared to all other pediatric recipients between two and 18 years of age who received renal transplants over the same time period. Five year graft survival for recipients less than two years of age was 86% following living-related donor transplantation and 38% following cadaver donor transplantation. Older pediatric recipients aged between two and 18 years had a five year graft survival of 73% following living-related donor renal transplantation, which was similar to that for recipients less than two years of age. Although older cadaveric recipients had a comparable five year graft survival to younger recipients, at 42%, the patterns of graft loss were different. Graft failures in young recipients occurred within the first seven months post-transplant, whereas the older recipient's grafts failed more gradually. Actuarial five-year patient survival in recipients less than two years of age was 86% following living-related donor renal transplantation and 70% following cadaver-donor renal transplantation. Recipients less than two years of age had a poorer patient survival than older recipients following both living-related donor renal transplantation (P = 0.06) and cadaver-donor renal transplantation (P less than 0.05). These findings suggest that the graft survival of living-related donor renal transplantation in recipients less than two years of age is better than that of cadaver-donor renal transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of cadaver donor age on posttransplant renal function and graft outcome

To assess the impact of cadaver donor age on posttransplant renal function and graft survival, we analyzed our clinical results in 17 recipients of younger donor kidneys (less than 10 years) and 48 recipients of older donor kidneys (greater than 50 years) and compared them with a control group of 598 patients who received kidneys from donors between 11 and 50 years of age. The 3 groups were comparable with respect to recipient age, duration of dialysis, prior transfusions, previous transplants, cold ischemia time, HLA AB mismatches, cytotoxic antibody profile, posttransplant ATN, and prophylactic ALG treatment. The cumulative patient survival at 1, 2, and 3 years was not significantly different among the 3 groups, but the graft survival in recipients of older donor kidneys was significantly lower than the control (71% vs. 62% at 2 years, P = .09 and 66% vs. 55% at 3 years, P = .0003. The short-term renal function assessed at 1 month posttransplant was significantly lower in the older donor group compared with the control (creatinine clearance 45 mL/min vs. 59 mL/min, P = .0003). Likewise, the long-term renal function assessed at the last follow-up was also lower in the older donor group than the control (creatinine clearance 40 mL/min vs. 49 mL/min, P = .07). There were no significant differences in graft survival or short- or long-term renal function between the younger donor group and the control group. These observations suggest that transplantation of a kidney from an older cadaver donor is associated with an inferior posttransplant outcome. The practical decision whether or not to use an older donor kidney should be individualized taking this as well as other factors into account.     

Thyroid Hormone in the Treatment of Post-transplant Acute Tubular Necrosis (ATN)

Delayed graft function (DGF) in cadaver kidney transplants is a common problem and is often due to acute tubular necrosis (ATN). DGF in transplants may have a deleterious effect on long-term graft survival. Since thyroid hormone has been shown to hasten recovery from ATN in experimental models, we designed a trial to determine if a defined course of triiodothyronine (T3) would improve the short- or long-term outcome of patients with DGF in cadaveric transplants. A prospective, randomized, placebo controlled, double blind trial of T3 was carried out in patients with DGF in cadaveric renal transplants. End-points were percentage requiring dialysis, percentage recovering function, time to recovery and length of hospital stay. Long-term outcomes were percentage grafts functioning at 1 year and mean serum creatinine at 1 year. Forty-four patients were randomized to receive either T3 or placebo. Three patients were dropped from each group when early biopsies disclosed that DGF was due to rejection. The groups were well matched by age, cold ischemia time of the graft, and percentage reactivity to a random panel of antigens. Baseline thyroid function studies, including T3, reverse T3 (rT3), and thyroid stimulating hormone (TSH) levels, were similar between the two groups and typical of 'euthyroid-sick syndrome'. T3 had no effect on percentage requiring dialysis, time to recovery, percentage recovering function, or length of stay. At 1 year follow-up, graft function was similar in both groups and significantly lower than that seen in patients with good initial function. Thyroid hormone, given early in the course of DGF in cadaver kidney recipients, had no effect on the course of DGF. Long-term graft function is impaired in patients who experience post-transplant DGF compared to those who have good initial function.     

Kidney retransplantation in the cyclosporine era

The results of kidney retransplantation in the cyclosporine era remain to be determined. Over a 42-month period, 76 nonprimary renal transplants (66 second, 7 third, 3 fourth allografts) were performed in 73 recipients under cyclosporine immunosuppression. The patient population was predominantly white (90.4%) with a mean age of 32.3 years. Twenty-one recipients (28.8%) were diabetic, and 36 (49.3%) were highly sensitized (panel-reactive antibody [PRA] greater than 50%). Sixty-two patients received cadaver donor grafts while the remaining donations were living-related (12) or living-unrelated (2). A sequential antilymphocyte globulin/cyclosporine protocol was employed, with cyclosporine therapy delayed until adequate renal function occurred. Overall patient and graft survival is 92.1% and 60.5%, respectively, after a mean follow-up of 20.0 months. The mean serum creatinine is 1.64 mg/dl in the 46 functioning allografts. Graft survival is 63.6% for secondary grafts, 28.6% for tertiary grafts, and 66.7% for fourth kidney transplants. In second transplants, recipients of cadaver donor kidneys have a graft survival of 58.5%, while living-related donor graft survival is 84.6% (P = 0.07). In the cadaver retransplant population, duration of previous transplant function greater than one year and HLA-DR matching were associated with increased graft survival, while age over 39 and presence of diabetes mellitus with reduced graft survival. However, these trends were not significant. Peak PRA above 50% did demonstrate a significant negative impact on graft survival both in the univariate and multivariate analyses of risk factors. Acute rejection occurred in 50 patients (65.8%), and was successfully reversed 50% of the time. Of the 30 grafts lost, 25 (83.3%) occurred within four months of retransplantation. Transplant nephrectomy was performed in 20 patients. Cyclosporine was not administered in 21 (70%) of these early graft failures, negating any potential beneficial effect. Retransplantation can be performed safely, with living-donor graft survival superior to cadaver retransplant rates. Rejection and early graft loss are common, especially in the highly sensitized patient. The impact of cyclosporine immunosuppression in renal retransplantation is much less dramatic than in primary transplantation in a protocol that delays cyclosporine therapy until allograft function is demonstrated.     

The combined impact of donor age and acute rejection on long-term cadaver renal allograft survival

BACKGROUND: Acute rejection (AR) is an important risk factor for long-term renal graft loss. Furthermore, donor age is also associated with graft outcome. We analyzed the combined effects of cadaver donor age and AR on long-term graft survival. METHODS: A retrospective review was made of 112 cadaver renal transplants at a single center. Only grafts functioning at least 3 months were included in this analysis. RESULTS: The 3-year survival of AR-free grafts was superior to that of grafts with AR (98% vs 67%, P < .001). Within the AR cohort donor age > 50 years (P < .05) had an additional negative impact on graft survival. The 3-year survival of an older donor graft with AR was 33% versus 82% for a younger donor graft with AR. CONCLUSIONS: AR was a significant predictor of long-term graft loss. Older donor kidneys with AR had poorer graft survival than did younger donor kidneys with AR.     

Unrelated living donor kidney transplantation

Since 1966, we have performed 41 renal transplants from unrelated living donors (ULD), 39 of which were emotionally related. All donor-recipient pairs included in the present series were AB0-compatible. Recipients included 37 with primary and 4 with secondary transplants; 2 of the latter were diabetics. We compared these results to those of 41 recipients of cadaver donor kidneys matched for age, sex, immunosuppressive regimen, rank, and year of transplant, focusing our attention of the subgroups of patients under cyclosporin A (CyA) therapy (n=24). We found that ULD transplantation was as successful as cadaver transplantation with good HLA matching: at 3 years, graft survival rates were 81% in ULD versus 86% in the control group under CyA. Moreover, grafts from ULD functioned more rapidly (no post-transplant dialysis and 70% of the patients with serum creatinine below 2 mg/dl within 3 days post-transplant). Graft tolerance was equivalent in both groups (50% of the patients experienced no rejection). We conclude that despite poor HLA matching, ULD transplantation with CyA as the basic immunosuppressive agent offers good results: benefiting from the quality of living donor kidney grafts, it helps to alleviate the persistent shortage of cadaver donors.     

Improved Scoring System to Assess Adult Donors For Cadaver Renal Transplantation

We previously proposed a quantitative approach to assess donor organs for cadaver renal transplantation. To improve on our original scoring system, we studied 34 324 patients who received cadaver renal transplants from adult donors between 1994 and 1999 and were reported to the UNOS Scientific Renal Transplant Registry. A scoring system was developed from five donor variables (age, 0-25 points; history of hypertension, 0-4; creatinine clearance before procurement, 0-4; cause of death, 0-3; HLA mismatch, 0-3) that showed a significant correlation with renal function and long-term graft survival. Cadaver kidneys were stratified by cumulative donor score: grade A, 0-9 points; grade B, 10-19; grade C, 20-29; and grade D, 30-39. The influence of donor score on renal function and graft survival was most severe above 20 points, designated 'marginal' kidneys. In summary, a donor scoring system developed from a large population database was useful in predicting outcome after cadaver renal transplantation. The improved system provides a quantitative approach to evaluation of marginal kidneys and may improve allocation of these organs in cadaver renal transplantation.     

The large center variation in half-lives of kidney transplants.

Based on a log-linear model for analyzing multiple effects, center variation in the UCLA Transplant Registry is the most influential factor in early renal graft survival. Among 68 active centers accounting for 70% of all transplants between 1985 and 1989, the 1-year graft survival (adjusted for 15 covariates) varied from 60 to 90%. The long-term graft survival, as measured by the half-lives of the first cadaver donor transplants at these centers, based on a minimum of 4 years of follow-up data, varied from 3 to 26 years. Although there was some correlation (r = 0.24) of half-life with the 1-year graft survival rate at each center, in many instances, excellent centers had poor half-lives and average centers had excellent half-lives. From a Cox regression analysis on data from 6752 first cadaver-donor renal transplants surviving beyond 1 year (submitted to the UNOS data base), white female recipients of 0 HLA-AB-mismatched kidneys not requiring dialysis in the first week posttransplant had projected half-lives of 14.1 years, whereas black male recipients of 4 HLA-AB-mismatched kidneys requiring therapeutic dialysis had half-lives of 2.3 years. However, adjustment for these factors could only remove 17% of the total variability in the centers' half-lives. Consequently, any algorithm intended to judge a center's renal transplant capabilities should include, even after adjustment for covariates, some function of both 1-year graft survival and half-life beyond 1 year.     

Living unrelated donor kidney transplantation

BACKGROUND: Living unrelated donors remain an underutilized resource, despite their high graft survival rates. In this article, we updated the long-term results of more than 2500 living unrelated donor transplants performed in the United States. METHODS: Between 1987 and 1998, 1765 spouse, 986 living unrelated, 27,535 living related, and 86,953 cadaver donor grafts were reported to the United Network for Organ Sharing Kidney Registry. Kaplan-Meier curves compared graft survival rates in stratified analyses, and a log-linear analysis adjusted donor-specific outcomes for the effects of 24 other transplant factors. RESULTS: The long-term survival rates for both spouse and living unrelated transplants were essentially the same (5-year graft survivals of 75 and 72% and half-lives of 14 and 13 years, respectively). The results were similar to that for parent donor grafts (5-year graft survival = 74% and half-life = 12 years) and were significantly (P = 0.003) better than cadaver donor grafts (5-year graft survival = 62% and half-life = 9 years). After adjusting for the presence of transplant factors known to influence survival rates, recipients of living unrelated donor kidney transplants still had superior outcomes compared with cadaver transplants. CONCLUSIONS: Living unrelated kidney donors represent the fastest growing donor source in the United States and provide excellent long-term results. Encouraging spouses to donate could remove nearly 15% of the patients from the UNOS waiting list, effectively increasing the number of available cadaveric organs.     

Late results of renal transplantation

A total of 315 (64%) of 491 primary cadaver and living-related donor transplants performed from 1975 through 1984 were still functioning at 24 months. These selected patients were examined further to assess the impact of several risk factors on late graft and patient survival. Black recipients, patients with underlying diabetes mellitus or hypertension, patients with poor renal function at 24 months, and recipients of cadaver grafts had significantly poorer long-term graft survival. Age greater than or equal to 40, diabetes or hypertension, poor 24-month function, and cadaver donor transplantation were associated with poorer long-term patient survival. Considerable improvement in graft survival at 24 months was seen in 1980-1984 compared with the earlier period, coincident with our adoption of routine pretransplant random donor blood transfusion. In contrast, long-term graft survival in patients with functioning graft at two years did not improve significantly over the same period. Although living-related donor transplants showed greater graft and patient survival than cadaver donor grafts by univariate analysis, no such advantage was demonstrated by multivariate analysis.