Renal transplantation in the elderly

Immunosenescence as a reason of individualizing immunosuppressive therapy in kidney transplantation

Transplantation in elderly patients is obviously more challenging due to existing underlying diseases, changes in pharmacokinetics of immunosuppressive drugs, polypragmasy, and transformation of immunoreactivity (immunosenescence). Our review presents data on modification of adaptive and innate immunity during aging. It also considers the possibility of both reduced and adapted immunosuppressive therapy in elderly renal transplant recipients in achieving an optimal balance between efficacy and complications.

Immunosuppression Regimen Use and Outcomes in Older and Younger Adult Kidney Transplant Recipients: A National Registry Analysis

BACKGROUND

Although the population of older transplant recipients has increased dramatically, there are limited data describing the impact of immunosuppression regimen choice on outcomes in this recipient group.

METHODS

National data for US Medicare-insured adult kidney recipients (N = 67 362; 2005-2016) were examined to determine early immunosuppression regimen and associations with acute rejection, death-censored graft failure, and mortality using multivariable regression analysis in younger (18-64 y) and older (>65 y) adults.

RESULTS

The use of antithymocyte globulin (TMG) or alemtuzumab (ALEM) induction with triple maintenance immunosuppression (reference) was less common in older compared with younger (36.9% versus 47.0%) recipients, as was TMG/ALEM + steroid avoidance (19.2% versus 20.1%) and mammalian target of rapamycin inhibitor (mTORi)-based (6.7% versus 7.7%) treatments. Conversely, older patients were more likely to receive interleukin (IL)-2-receptor antibody (IL2rAb) + triple maintenance (21.1% versus 14.7%), IL2rAb + steroid avoidance (4.1% versus 1.8%), and cyclosporine-based (8.3% versus 6.6%) immunosuppression. Compared with older recipients treated with TMG/ALEM + triple maintenance (reference regimen), those managed with TMG/ALEM + steroid avoidance (adjusted odds ratio [aOR], 0.440.520.61) and IL2rAb + steroid avoidance (aOR, 0.390.550.79) had lower risk of acute rejection. Older patients experienced more death-censored graft failure when managed with Tac + antimetabolite avoidance (adjusted hazard [aHR], 1.411.782.25), mTORi-based (aHR, 1.702.142.71), and cyclosporine-based (aHR, 1.411.782.25) regimens, versus the reference regimen. mTORi-based and cyclosporine-based regimens were associated with increased mortality in both older and younger patients.

CONCLUSIONS

Lower-intensity immunosuppression regimens (eg, steroid-sparing) appear beneficial for older kidney transplant recipients, while mTORi and cyclosporine-based maintenance immunosuppression are associated with higher risk of adverse outcomes.

Impact of kidney transplant morbidity on elderly recipients' outcomes

BACKGROUND AND AIMS

Nowadays, advanced age does not represent an absolute contraindication to kidney transplantation (KT). However, aging is frequently associated with multiple comorbidities and lower performance status, making KT candidates less surgically fit. Limited data are available on the impact of KT morbidity on elderly recipients' outcomes.

METHODS

Retrospective study on a single center cohort of 130 KT recipients over 65 years old, representing 16.2% of KT clinical series, during the period 2000-2018. Number and severity of comorbidities were evaluated with the Charlson Comorbidity index (CCI).

RESULTS

The median age at transplantation was 67 [IQR66-71] years and median CCI was 5 [IQR4-6]. The prevalence of postoperative complications with a Clavien-Dindo (C-D) severity score > 2 was 29%. Increasing age did not predict KT morbidity in terms of C-D score > 2, infectious, respiratory, cardiologic, urologic or vascular complications, delayed graft function, symptomatic lymphocele, bleeding, acute or chronic rejection. Conversely, CCI score was a predictor of overall complications with C-D score > 2, cardiologic, respiratory and vascular complications, and bleeding. Among others, CCI score, post-KT cardiologic complications, C-D score > 2 were identified as significant predictors of both early mortality and graft loss in univariate analysis. Increasing recipient age did not correlate with graft loss risk and graft loss did not impact patient survival. C-D score > 2 was a predictor of poor survival even in multivariate analysis.

CONCLUSIONS

Elderly recipients showed a significant vulnerability to KT morbidity which correlates with CCI. While graft loss did not impact recipient survival, severe postoperative complications (C-D > 2) were independently associated increased mortality.

Characterizing the pharmacokinetics and pharmacodynamics of immunosuppressant medicines and patient outcomes in elderly renal transplant patients

This review examines what is currently known about the pharmacokinetics and pharmacodynamics of commonly prescribed immunosuppressant medicines, tacrolimus, cyclosporine, mycophenolate and prednisolone, in elderly renal transplant recipients, and reported patient outcomes in this cohort. Renal transplantation is increasing rapidly in the elderly, however, currently, long-term patient outcomes are relatively poor compared to younger adults. Some studies have suggested that elderly recipients may have higher dose-adjusted exposure and/or lower clearance of the calcineurin inhibitors tacrolimus and cyclosporine; with one study reporting up to 50% reduction in tacrolimus exposure in the elderly. Elderly transplant recipients do not appear to have higher dosage-adjusted exposure to mycophenolic acid (MPA). The effects of ageing on the pharmacokinetics of prednisolone are unknown. Only one study has examined how aging effects drug target enzymes, reporting no difference in baseline inosine 5'-monophosphate dehydrogenase (IMPDH) activity and MPA-induced IMPDH activity in elderly compared to younger adult renal transplant recipients. In elderly transplant recipients, immunosenescence likely lowers the risk of acute rejection, but increases the risk of drug-related adverse effects. Currently, the three main causes of death in elderly renal transplant recipients are cardiovascular disease, infection and malignancy. One study has showed that renal transplant recipients aged over 65 years are seven times more likely to die with a functioning graft compared with young adults (aged 18-29 years). This suggests that an optimal balance between immunosuppressant medicine efficacy and toxicity is not achieved in elderly recipients, and further studies are needed to foster long-term graft and patient survival. Lower maintenance immunosuppressant targets in elderly recipients may decrease patient susceptibility to drug side effects, however, further studies are required and appropriate targets need to be established.