The influence of donor age on graft survival

The impact of donor and recipient age on the outcome of kidney transplantation

BACKGROUND

As survival has improved in the general population over the last few decades, the age of patients participating in renal transplantation has also increased. This study sought to investigate the impact of donor and recipient age as predictors of long-term graft survival in renal transplantation.

MATERIALS AND METHODS

We analyzed transplantation outcomes in 598 patients who received renal transplants from 1979 to 2002. Patients were divided into 4 groups according to their age at renal transplantation. Group A (donor age <50 years, recipient age >50 years, n = 19/3.2%); group B (donor age >50 years, recipient age <50 years, n = 153/25.5%); group C (donor age <50 years, recipient age >50 years, n = 69/11.6%), and group D (donor age <50 years, recipient age <50 years, n = 357/59.8%). Univariate analysis to assess the effect of donor and recipient age as predictor factors of graft outcome was complimented by Kaplan-Meier and log-rank methods to assess graft survival with P < 1.05 considered significant.

RESULTS

In the elderly donor group, graft survival was 92.8% at 1 year and 85.6% at 3 years; in the younger donor group, they were 93.4% and 90.2%, respectively, a difference that was statistically significant (P = .02). Univariate analysis of age factors showed a significant reduction in graft survival among recipients who received kidneys transplants from donors older than 50 years, although recipient age >50 years was not found to be an independent risk factor. The incidence of acute rejection was 24.6% in the elderly donor group and 23.5% in the younger donor group (P = not significant). Among the 4 groups, the best result was group D with 1-year and 3-year graft survival rates of 93.3% and 90.5%, respectively, but this result was not statistically significant.

CONCLUSIONS

These results may help the design for transplantation strategies for kidneys procured from elderly donors and for allocation to elderly recipients.

The use of expanded criteria cadaver and live donor kidneys for transplantation

The use of expanded criteria donors (non-traditional donors) can help lessen the current shortage of kidneys available for transplantation. The use of older donors has accounted for a large measure of the increase in the organ donation rate; however, the most significant factors found to impact on transplant success negatively traditionally have been shown to be extremes of donor age and last-hour urine output. Less significant variables affecting success rates are average systolic blood pressure, terminal serum creatinine, and days of hospitalization. With the appropriate selection of organs from expanded donors, acceptable outcomes can be obtained. When living donors are selected properly, kidneys with anatomic variants without pathologic significance can be used safely. Kidneys with a heightened potential for the development of progressive disease should not be transplanted. Efforts to decrease the cold ischemia time by increasing the use of kidneys from expanded criteria donors may improve the outcome of transplantation further. Advances in surgical techniques, preservation solutions, and methods for predicting eventual long-term renal function in kidneys from expanded donors will be critical in allowing precise selection criteria for kidneys for transplantation, resulting in the optimum use of a scarce and precious resource. Until options such as xenotransplantation become clinically feasible, the challenge will be to identify which donor organs previously considered suboptimal can be used safely to expand the organ donor pool.

Older donors and kidney transplantation

Reluctance to use kidneys from older donors (> 50 years of age) is based on reports of inferior results. We reviewed our experience with 45 kidneys transplanted from older donors. Primary nonfunction, immediate graft function, and 1-, 2- and 3-year graft survival rates were similar to those obtained with kidneys transplanted from donors aged between 20 and 40 years. Renal function at 1 year (as measured by serum creatinine) was poorer in kidneys from older donors. No beneficial effect with respect to graft survival was noted with cyclosporin therapy compared to conventional immunosuppression; however, the numbers are small. We conclude that kidneys from older donors are a valuable source for transplantation.

Cadaveric kidney donation beyond the age of 60 years--a comparative analysis of 1180 grafts from different donor age groups

The impact of high donor age on transplantation outcome was analysed in 1180 consecutive cadaveric grafts transplanted in adult recipients. Grafts were divided into three groups acording to donor age (< 55 years (n = 1073, group 1), 55-59 years (n = 51, group 2), > or = 60 years (n = 56, group 3)) and transplantation outcome was compared for these groups. Criteria investigated were the incidence of primary non-function (PNF), initial function (IF) (urine production first 24 h) and long-term function (LTF). The impact of donor age on LTF was analysed among other potential donor, graft and recipient risk factors by the multivariate proportional hazardous model analysis (Cox model). The incidence of PNF was 5.8% (group 1), 11.8% (group 2), and 16.1% (group 3) (P = 0.002). Analysis of paired kidneys of PNF grafts in group 2 and group 3 revealed good function for all paired grafts except for one in each group. IF was anuria in 19.7% of group 1, 29.4% group 2 and 21.5% of group 3, oliguria in 18.2% of group 1, 23.5% of group 2 and 32% of group 3. Normal diuresis was found in 62.1% of group, 47.1% of group 2 and 47.3% of group 3 (P = 0.05). Independent risk factors for graft survival were year of transplantation, recipient age, panel reactive antibodies, donor age group and number of transplantation. After the exclusion of PNF grafts from the analysis, recipient age, year of transplantation and level of panel reactive antibodies remained as independent risk factors.

Donor-recipient age difference--an independent risk factor in cyclosporin-treated renal transplant recipients

Whilst HLA matching is routine in renal transplantation the possible benefits of matching donor to recipient age have not been previously explored. The simultaneous effect on graft survival of donor and recipient age was therefore investigated for 274 consecutive first cadaver transplant recipients treated by cyclosporin immunosuppression in two centres. The overall graft survival was 77%, and was not significantly different between the two centres. Individually there was no significant effect of donor or recipient age but taken together, the difference in age significantly affected graft survival (P less than 0.01) regardless of the mode of failure. The 1-year graft survival for all failures was 66.2% when the donor was 5 or more years older. 84.5% when the donor was 5 or more years younger and 71.7% when the donor was within 5 years of the recipient's age. Multivariate analysis, taking into account other variables (HLA matching, dialysis time and type, donor/recipient sex, local/imported kidneys, sensitivity, operation time, total ischaemic time, pre-operative transfusions) indicated that age difference was the single most important variable (P less than 0.01). The only other important covariate risk factor in improving graft survival was HLA-DR matching (P less than 0.05). Donor-recipient age difference is a potentially important recipient selection criterion in cyclosporin-treated renal transplant patients.

The organ donor

Vascularized organ transplantation is now a widely applied therapy for patients with end-stage diseases of the heart, lungs, liver, kidneys, and pancreas. A critical shortage of donor organs exists in the United States and, as a consequence, prospective transplant recipients die while waiting for a life-saving transplant. The apparent shortage of cadaver organs is, in large part, caused by the reluctance and failure of the physician and the public to promote cadaver organ donation. Educational awareness programs for both professional personnel and the public at large are needed to increase the number of potential donors and multiorgan procurements carried out. All victims of trauma with severe closed head injury or cerebrovascular catastrophe secondary to anoxia should be considered as potential organ donors and referred to the local organ procurement agency for evaluation.

Use of older patients as cadaveric kidney donors

We have no fixed upper age limit for cadaveric kidney donors and donors over the age of 50 provided kidneys for 22 per cent of our adult transplant recipients between 1983 and 1986. Immediate function following transplantation occurred in 17 per cent of these kidneys compared with 58 per cent for kidneys from donors under the age of 50. The 1-year actuarial graft survival rate for transplants from donors over 50 was 52 per cent, compared with 70 per cent for transplants from donors under 50 (P less than 0.05). Thus kidneys from older donors make an important contribution to the total pool of organs available for transplantation, but their use leads to inferior results in comparison with kidneys from younger donors.

Renal transplantation of the infant and young child and the use of pediatric cadaver kidneys for transplantation in pediatric and adult recipients

Transplantation of infants less than 1 year of age with kidneys from live-related parental donors has recently led to good results, whereas cadaver donor renal transplantation in this recipient age group has led to a high mortality rate (11/13). Similarly, the results of cadaver donor renal transplantation in infants and young children less than 5 years of age has been suboptimal in the past, although recent data are more encouraging. With recent availability of long-term peritoneal dialysis for the infant and young child with end-stage renal disease (ESRD), it is possible to defer transplantation until an optimal donor becomes available. Because of the possible immunologic hyperactivity of such recipients, the immunosuppressive regimen may need to be modified if improved cadaver donor survival rates are to be obtained. The use of anencephalic kidneys for transplantation has been associated with a high incidence of primary nonfunction and few recipients with long-term functioning grafts. Harvesting of kidneys from anencephalic donors declared "brain-dead" at birth may reduce the incidence of primary nonfunction and increase the availability of anencephalic kidneys for transplantation. Reports of the use of pediatric cadaver kidneys for transplantation into pediatric and adult recipients yields discrepant results. Analysis of the data indicates that if pediatric cadaver kidneys from donors less than 6 years of age are used, the potential for decreased graft survival rates and an increased incidence of technical complications exists. However, the use of pediatric cadaver kidneys can provide adequate graft function in both pediatric and adult recipients and the use of such kidneys should increase the number of kidneys available for transplantation.

The influence of donor age on renal function in transplant recipients

To the extent that age-related declines in kidney function are caused by intrarenal alterations, donor age should affect glomerular filtration rate (GFR) after renal transplantation. Although some investigations have suggested that transplantation of aging kidneys may cause an increased incidence of primary allograft failure, the effects of donor age on GFR are unknown. In the present study, 201 patients who had allografts that survived for at least 24 months were investigated. The age range of the donors was 7 to 61 years. Multivariate regression analysis demonstrated that both donor and recipient age had significant, independent effects on creatinine clearance at 1 year, and at last follow-up, 5.0 +/- 1.9 years (mean +/- SD) after transplantation. The effect of donor age on renal function could not be attributed to differences in the number of rejection episodes, the frequency or duration of posttransplant acute tubular necrosis, age of the recipient, or other factors. Donor age had no effect on allograft survival, and did not affect the rate of decline in creatinine clearance between 1 year and last follow-up. Thus, these results suggest that donor age is associated with intrarenal alterations that lead to reductions in renal function after transplantation, but donor age may not affect long-term prognosis or allograft survival in the late posttransplant period.

Pediatric cadaver kidney transplants into adults

During a 5-year period 77 adults received single kidney cadaver transplants from donors 16 months to 16 years old. Cyclosporin immunosuppression was not used. Three recipients had ischemic ureteral complications, 1 of which resulted in allograft loss. Of the kidney grafts 34 were from donors 8 years old or younger, and comparison of renal function was made with the 43 adult recipients of cadaver kidneys from older children. The mean 1-month serum creatinine nadir was significantly higher in the recipients of kidneys from the younger children (2.6 plus or minus 1.6 versus 1.9 plus or minus 0.8 mg./per dl.). There were no statistically significant differences in 1-week dialysis requirement, 1-month kidney graft function or actuarial kidney graft survivals and serum creatinine levels at 3, 6, 12 and 24 months after grafting. Cadaver kidneys from young donors can be transplanted successfully into adults.

The older living renal donor: prognosis for the donor and recipient

Results after 46 renal transplants from living donors more than 50 years old are presented. There were no complications after transperitoneal nephrectomy and renal function remained stable in all donors. The mean followup for transplant recipients was 6.2 years. The 2-year patient and graft survival rates were 76.1 and 60.9 per cent, respectively, while the corresponding 5-year rates were 60.5 and 46.5 per cent, respectively. These results suggest that age per se should not eliminate living related kidney donation.