Living donor age and kidney transplant outcomes

Expanded Criteria Donors in Kidney Transplantation: The Role of Older Donors in a Setting of Older Recipients

Kidney transplantation (KT) is the therapy of choice for end-stage renal disease (ESRD). The ESRD population is aging and so are patients waiting for KT. New strategies have been made for increasing the donor and recipient pools, and as a consequence kidneys from older donors or donors with significant comorbidities, the so-called “expanded criteria donor” (ECD) kidneys, are used for transplantation. Although good outcomes have been achieved from ECD, several issues are still waiting for clarification and need to be discussed. The concept of age matching is accepted as a method to ameliorate utilization of these allografts, but an optimal and widely accepted strategy is still not defined. The development of machine perfusion and the dual kidney transplantation are techniques which further improve the outcome of transplants from ECD, but the described experiences are scarce or coming from small single institutional reports. Also due to age-related immune dysfunction and associated comorbidities, the elderly recipients are more susceptible to immunosuppression related complications (e.g., infections and malignancy), although a widely accepted and validated immunosuppressive regimen is still lacking. In this paper, we review the issues related to KT employing allografts from marginal donors with a particular interest for the elderly patients.

Long-term impact of hypertension on renal allografts

OBJECTIVE

We assessed the impact of hypertension on renal transplant function and survival in the past decade after introduction of mycophenolate mofetil and rituximab.

METHODS

We examined the 184 patients who underwent renal transplantation from March 1982 to September 1999 and presented at our outpatient clinic from 2001 to 2011. They were divided into group 1 with mean systolic blood pressure (mSBP) >130 mm Hg and Group 2 with mSBP <130 mm Hg. We compared mean serum creatinine (sCr) levels for 9 years and 12-year actuarial graft survival rates. Risk factors for graft survival were assessed by Cox regression analysis.

RESULTS

There were 75 group 1 and 109 group 2 recipients. The mean sCr level of group 1 was 1.59 ± 0.12 mg/dL and that of group 2 1.54 ± 0.10 mg/dL (P < .0001). Of note was that mean sCr levels of group 1 started to increase about 3 years after transplantation. Although 5-year graft survival rates of both groups were 100%, 9- and 12-year rates among group 1 were 97.3% and 90.5%, respectively, whereas among group 2 they were 99.1% and 98.1%, respectively (P = .0195). Cox univariate and multivariate analyses showed mean SBP to be the only significant risk factor for graft survival (P < .05).

CONCLUSIONS

We concluded that the hypertensive group showed deteriorating renal function from around 3 years after transplantation that lowered graft survival afterward, resulting in a clear distinction from the nonhypertensive group at around 10 years after transplantation. Mean SBP was a significant risk factor for graft survival. Hypertension may be a surrogate for a poor renal graft prognosis in the long run.

Living donor age and kidney allograft half-life: implications for living donor paired exchange programs

BACKGROUND AND OBJECTIVES

Living donor paired exchange programs assume that kidneys from living donors are of comparable quality and anticipated longevity. This study determined actual allograft t(1/2) within different recipient age groups (10-year increments) as a function of donor age (5-year increments), and juxtaposed these results against the probabilities of deceased donor transplantation, and exclusion from transplantation (death or removal from the wait-list).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from the US Renal Data System (transplant dates 1988-2003 with follow-up through September 2007) were used to determine allograft t(1/2), whereas data from patients on the United Network for Organ Sharing waiting list between 2003 and 2005 (with follow-up through February 2010) were used to determine wait-list outcomes.

RESULTS

With the exception of recipients aged 18-39 years, who had the best outcomes with donors aged 18-39 years, living donor age between 18 and 64 years had minimal effect on allograft t(1/2) (difference of 1-2 years with no graded association). The probability of deceased donor transplantation after 3 years of wait-listing ranged from 21% to 66% by blood type and level of sensitization, whereas the probability of being excluded from transplantation ranged from 6% to 27% by age, race, and primary renal disease.

CONCLUSIONS

With the exception of recipients aged 18-39 years, living donor age between 18 and 64 years has minimal effect on allograft survival.