Impact of donor age on renal allograft function and survival

Clinical factors associated with severe hypophosphataemia after kidney transplant

BACKGROUND

The mechanism by which hypophosphataemia develops following kidney transplantation remains debated, and limited research is available regarding risk factors. This study aimed to assess the association between recipient and donor variables, and the severity of post-transplantation hypophosphataemia.

METHODS

We performed a single-centre retrospective observational study. We assessed the association between demographic, clinical and biochemical variables and the development of hypophosphataemia. We used linear regression analysis to assess association between these variables and phosphate nadir.

RESULTS

87.6% of patients developed hypophosphataemia. Patients developing hypophosphataemia were younger, had a shorter time on renal replacement therapy, were less likely to have had a parathyroidectomy or to experience delayed graft function, were more likely to have received a living donor transplant, from a younger donor. They had higher pre-transplantation calcium levels, and lower alkaline phosphatase levels. Receipt of a living donor transplant, lower donor age, not having had a parathyroidectomy, receiving a transplant during the era of tacrolimus-based immunosuppression, not having delayed graft function, higher pre-transplantation calcium, and higher pre-transplantation phosphate were associated with lower phosphate nadir by multiple linear regression.

CONCLUSIONS

This analysis demonstrates an association between variables relating to better graft function and hypophosphataemia. The links with biochemical measures of mineral-bone disease remain less clear.

Kidney Discard Rates in the United States During American Transplant Congress Meetings

Supplemental digital content is available in the text.

Background

Deceased-donor kidney discard rates vary by region, but it is unknown whether discard rates and transplant outcomes vary during the American Transplant Congress (ATC) each year.

Methods

Using national registry data, we determined rates of kidney discard, delayed graft function, graft failure, and mortality from December 31, 1999, through December 30, 2015, during ATC dates and compared these rates with those on the same days of the week during the 2 weeks before and after the ATC (non-ATC). We used multivariable regression to determine associations between ATC and these outcomes.

Results

From 7902 donors (1575 ATC; 6327 non-ATC), 12 588 recipients received kidney transplants (2455 ATC; 10 133 non-ATC), and 2666 kidneys were discarded (582 ATC; 2084 non-ATC). Kidneys were more often discarded during ATC (19% vs 17%, P = 0.006; adjusted odds ratio, 1.21; 95% confidence interval, 1.05-1.40). There were no significant differences in donor, transplant, or recipient characteristics by ATC/non-ATC dates or by ATC/non-ATC transplant dates for delayed graft function, graft failure, or mortality.

Conclusions

On the basis of a 21% increased odds of discard, the ATC itself may result in 5 additional kidney discards during this important conference every year, which suggests the need for innovative staffing or other logistic solutions during these planned meetings.

Kidney Transplantation From Old Deceased Donors: Impact of Uric Acid Level-A Quarter-Century of Experience in One Transplant Center

BACKGROUND

The long-term burden of higher donor age on graft function and survival after kidney transplantation remains uncertain. Because both recipient and donor characteristics have evolved and the general population age is on the increase, we looked at the causes of kidney graft outcome.

AIM

The aim of this study was to evaluate the impact of different clinical parameters on long-term outcome of older-donor kidney transplantation. This retrospective study included 345 adult patients (58 patients received kidney from donors at least 55 years old) transplanted between January 1993 and December 2005 and were followed in one center throughout the post-transplant course (median, 9.4 years). Data included recipient and donor age, cold ischemia time, delayed graft function, panel reactive antibodies, HLA mismatch, time on dialysis, graft function at different time points, uric acid level, proteinuria, immunosuppression, and biopsy-proven rejection.

RESULTS

Improvement of estimated glomerular filtration rate at 36 months after transplantation was a good prognostic factor for long-term kidney function. Higher donor age decreased the chance for improvement of kidney function by 2.8% per year of life (P = .0244). Hyperuricemia was found in 46% of the study population; estimated glomerular filtration rate less than 50 mL/min/1.72 m² was associated with hyperuricaemia. A higher uric acid level was associated with inferior kidney function in recipient of older kidneys. Graft failure occurred late (median, 6.3 years post-transplantation) in 26 (44.8%) of older-donor recipients and in 87 (30.3%) of the remaining patients.

CONCLUSIONS

Our results suggest an important association between older donor age and decreased allograft function in kidney recipients with elevated uric acid level. Recipients of older kidneys with normal uric acid level presented satisfactory outcomes.

Does kidney transplantation with deceased or living donor affect graft survival?

Background:

There are growing numbers of patients with end-stage renal disease globally at an unexpected rate. Today, the most serious challenge in transplantation is organ shortage; hence, using deceased donor is increasingly encouraged.

Objectives:

The aim of the study was to investigate the differences in survival rates between kidney transplant recipients with deceased donor and living donor.

Patients and Methods:

In a retrospective cohort study, 218 patients who had undergone kidney transplantation in our institute from April 2008 to September 2010 were recruited. Demographics and post-transplantation follow-up data including immunosuppression regimens, rejection episodes, and survival rates were evaluated. The patients were assigned to two groups according to the donor kidney transplantation: group I, living donor kidney transplants; and group II, deceased donor kidney transplants.

Results:

Although there were no significant differences in one-year survival rates of patient and graft between study groups, three-years survival rates of patient and graft were significantly longer in living donor kidney transplants in comparison with the deceased donor kidney recipients (P = 0.006 and P = 0.004, respectively). In Cox-regression model after adjusting for other confounding factors such as age, sex, diabetes mellitus, and first- or second-time transplantation, overall patient and graft survivals were also significantly shorter in deceased kidney transplantation than those who received kidney from a living donor (HR, 3.5; 95% CI, 1.2-10.4; and P = 0.02 for patient survival; and HR, 5.4; 95% CI, 1.5-19.5; and P = 0.009 for graft survival).

Conclusions:

We found acceptable short-term survival in both groups; however, living donor recipients continue to have better long-term patient and graft survival rates.

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.

Predicting the outcome of renal transplantation

OBJECTIVE

Renal transplantation has dramatically improved the survival rate of hemodialysis patients. However, with a growing proportion of marginal organs and improved immunosuppression, it is necessary to verify that the established allocation system, mostly based on human leukocyte antigen matching, still meets today's needs. The authors turn to machine-learning techniques to predict, from donor-recipient data, the estimated glomerular filtration rate (eGFR) of the recipient 1 year after transplantation.

DESIGN

The patient's eGFR was predicted using donor-recipient characteristics available at the time of transplantation. Donors' data were obtained from Eurotransplant's database, while recipients' details were retrieved from Charité Campus Virchow-Klinikum's database. A total of 707 renal transplantations from cadaveric donors were included.

MEASUREMENTS

Two separate datasets were created, taking features with <10% missing values for one and <50% missing values for the other. Four established regressors were run on both datasets, with and without feature selection.

RESULTS

The authors obtained a Pearson correlation coefficient between predicted and real eGFR (COR) of 0.48. The best model for the dataset was a Gaussian support vector machine with recursive feature elimination on the more inclusive dataset. All results are available at http://transplant.molgen.mpg.de/.

LIMITATIONS

For now, missing values in the data must be predicted and filled in. The performance is not as high as hoped, but the dataset seems to be the main cause.

CONCLUSIONS

Predicting the outcome is possible with the dataset at hand (COR=0.48). Valuable features include age and creatinine levels of the donor, as well as sex and weight of the recipient.