Immunosuppressant prescription pattern and trend in kidney transplantation: A multicenter study in Korea

Time-dependent impact of immunosuppressant regimens on cardiovascular outcomes in kidney transplant recipients: a nationwide cohort study

Objectives

We aimed to evaluate the effect of different immunosuppressive regimens on the risk of major adverse cardiovascular events (MACEs) in kidney transplant recipients (KTRs).

Methods

This retrospective cohort study used nationwide claims data from the Korean Health Insurance Review and Assessment Service from between 2010 and 2021. Immunosuppressive medications were analyzed as time-dependent variables, and the primary outcome was MACEs, defined as a composite of myocardial infarction, coronary revascularization, ischemic stroke, and all-cause mortality.

Results

A total of 8,056 KTRs were included in the analysis, with significant risk factors for MACEs identified as male sex, older age, longer dialysis duration, lower economic status, and greater comorbidity. At the time of the kidney transplant, 86.7% of the KTRs were administered standard triple therapy, after which various immunosuppressive regimens, including sirolimus-inclusive regimens, were employed. The risk of MACE was lower or comparable in KTRs standard triple therapy than in those receiving most other immunosuppressive regimens. However, corticosteroid withdrawal was associated with a significant reduction in cardiovascular risk, particularly in KTRs with preexisting diabetes or dyslipidemia.

Conclusion

These findings suggest that early consideration should be given to minimizing steroid use in KTRs with dyslipidemia or diabetes to optimize cardiovascular outcomes.

Optimizing Tacrolimus Dosing During Hospitalization After Kidney Transplantation: A Comparative Model Analysis

BACKGROUND The optimization of tacrolimus dosing during the early postoperative hospitalization period is essential to prevent rejection, minimize nephrotoxicity, and minimize the risk of opportunistic infections. Patient pharmacokinetic variability poses challenges in dose adjustment. This study aimed to evaluate tacrolimus dosing optimization using machine learning and statistical methods. MATERIAL AND METHODS We conducted a retrospective study of 749 kidney transplant recipients at Seoul St. Mary's Hospital between January 2015 and December 2019. Data on tacrolimus doses, trough levels, and other clinical variables were collected and analyzed during the first 12 postoperative days of hospitalization. Three approaches were evaluated: Extreme Gradient Boosting (XGBoost), Elastic Net regression (EN), and Linear regression (LR). The models were trained and validated using 5-fold cross-validation, with performance assessed using R² errors and alignment with clinically acceptable error margins. RESULTS Elastic Net showed the best performance with R² (Coefficient of Determination) of 0.861±0.044 and RMSE (Root Mean Square Error) of 0.930±0.220. Linear Regression and XGBoost provided clinically relevant predictions but with slightly lower accuracy. External validation was not performed, limiting the generalizability of the results. CONCLUSIONS The Elastic Net is a practical and reliable model for predicting the optimal tacrolimus dose. Machine learning and statistical methods are useful tools for optimizing tacrolimus dosing during hospitalization after kidney transplantation. Future studies should incorporate multi-center validation to improve clinical applicability.

Prescription Patterns of Mycophenolate Mofetil in a Group of Patients from Colombia

BACKGROUND

Mycophenolate mofetil is used for the prevention of solid organ transplant rejection and for other indications, such as systemic lupus erythematosus (SLE).

OBJECTIVE

To determine the prescription patterns of mycophenolate mofetil in a group of Colombian patients.

METHODS

This was a cross-sectional study of patients receiving mycophenolate mofetil between 2021 and 2022. The data were obtained from a drug dispensing database. Sociodemographic, clinical (diagnostic), and pharmacological variables were identified.

RESULTS

A total of 979 patients who underwent treatment were identified; their mean age was 45.9 ± 17.1 years, and 87.4% were women. The main diagnosis associated with the use of mycophenolate mofetil was SLE (39.1%), followed by other rheumatic diseases (8.5%), nephrotic syndrome (7.5%), and solid organ transplantation (6.4%). The relationship between the mean dose and the defined daily dose was 0.75. Ten percent of patients received mycophenolate alone, whereas 32.9% received mycophenolate in combination therapy with conventional disease-modifying antirheumatic drugs and glucocorticoids. A total of 76.2% had polypharmacy (five or more drugs).

CONCLUSIONS

Mycophenolate mofetil is used mainly in combination therapy for patients with SLE and other rheumatological diseases and for solid organ transplants at doses lower than those recommended.

HLA-DR/DQ eplet mismatch predicts de novo donor-specific antibody development in multi-ethnic Southeast Asian kidney transplant recipients on different immunosuppression regimens

Eplet mismatch has been recognized as a more precise strategy for determining HLA compatibility by analyzing donor-recipient HLA differences at the molecular level. However, predicting post-transplant alloimmunity using single-molecule eplet mismatch categories has not been validated in Asian cohorts. We examined a cohort of Southeast Asian kidney transplant recipients (n = 234) to evaluate HLA-DR/DQ eplet mismatch as a predictor of de novo donor-specific antibody (dnDSA) development. HLA-DR/DQ single-molecule eplet mismatch was quantified using HLA Matchmaker, and we utilized previously published HLA-DR/DQ eplet mismatch thresholds to categorize recipients into alloimmune risk groups and evaluate their association with dnDSA development. Recognizing that the predominance of cyclosporine use (71%) may alter published eplet mismatch thresholds derived from a largely tacrolimus-based (87%) cohort, we evaluated cohort-specific thresholds for HLA-DR/DQ single-molecule eplet mismatch categories. Recipient ethnicities included Chinese (65%), Malays (17%), Indians (14%), and others (4%). HLA-DR/DQ dnDSA developed in 29/234 (12%) recipients after a median follow-up of 5.4 years, including against isolated HLA-DR (n = 7), isolated HLA-DQ (n = 11), or both (n = 11). HLA-DR/DQ single-molecule eplet mismatch risk categories correlated with dnDSA-free survival (p = 0.001) with low-risk recipients having a dnDSA prevalence of 1% over 5 years. The cohort-specific alloimmune risk categories improved correlation with HLA-DR/DQ dnDSA-free survival and remained significant after adjusting for calcineurin inhibitor and anti-metabolite immunosuppression (p < 0.001). We validated the performance of single-molecule eplet mismatch categories as a prognostic biomarker for HLA-DR/DQ dnDSA development in a cohort of predominantly Asian kidney transplant recipients after adjusting for different immunosuppression regimens.

Toll-Like Receptor 3 mRNA Expression of Peripheral Blood Mononuclear Cells Identifies Kidney Recipients with Potential for Improved Graft Performance

BACKGROUND Toll-like receptor 3 expression is detected both on the cell membrane and in endosomes of peripheral blood mononuclear cells (PBMC). Our goal in this study was to determine to what extent a single, baseline measurement of non-stimulated PBMC TLR3-mRNA can be related to baseline GFR (b-GFR) and post-follow-up-GFR (F-up-GFR) of a kidney transplant (KT) and baseline immunosuppression. MATERIAL AND METHODS In non-stimulated PBMC we investigated averaged mRNA expression of Toll-like receptor 3. A total of 133 patients were enrolled; the median of months after KT surgery was 11.4, with median F-up at 21.3 months. A favorable course (FCF) was determined if F-up-eGFR improved. An unfavorable course (UCF) was determined if F-up-eGFR was lower at the end of the observation. RESULTS The highest TLR3-mRNA expression was at b-GFR grade 3b; it was moderately higher at b-GFR grade 3a, and marginally higher at b-GFR grades 1+2. Most of the FCF group had b-GFR grade 3b, less frequent obesity, more effective immunosuppression, and much higher TLR3-mRNA (59% of cases were in the high-TLR3 area). Both delayed graft function (DGF) and TLR3-mRNA range below the median for the entire KT cohort (low-TLR3 area) had a negative association with b-GFR. The UCF group had more frequent DGFs and obesity, less effective immunosuppression, and lower TLR3-mRNA. CONCLUSIONS In patients with GFR grade 3, high levels of TLR3-mRNA are associated with improved graft efficacy. In patients with impaired graft function, low TLR3- mRNA expression reduces the likelihood of improved renal graft function.

An Italian multicentre distributed data research network to study the use, effectiveness, and safety of immunosuppressive drugs in transplant patients: Framework and perspectives of the CESIT project

The goal of post-transplant immunosuppressive drug therapy is to prevent organ rejection while minimizing drug toxicities. In clinical practice, a multidrug approach is commonly used and involves drugs with different mechanisms of action, including calcineurin inhibitors (CNI) (tacrolimus or cyclosporine), antimetabolite (antimet) (mycophenolate or azathioprine), inhibitors of mechanistic target of rapamycin (mTOR) (sirolimus or everolimus), and/or steroids. Although evidence based on several randomized clinical trials is available, the optimal immunosuppressive therapy has not been established and may vary among organ transplant settings. To improve the knowledge on this topic, a multiregional research network to Compare the Effectiveness and Safety of Immunosuppressive drugs in Transplant patients (CESIT) has been created with the financial support of the Italian Medicines Agency. In this article, we describe the development of this network, the framework that was designed to perform observational studies, and we also give an overview of the preliminary results that we have obtained. A multi-database transplant cohort was enrolled using a common data model based on healthcare claims data of four Italian regions (Lombardy, Veneto, Lazio, and Sardinia). Analytical datasets were created using an open-source tool for distributed analysis. To link the National Transplant Information System to the regional transplant cohorts, a semi-deterministic record linkage procedure was performed. Overall, 6,914 transplant patients from 2009-19 were identified: 4,029 (58.3%) for kidney, 2,219 (32.1%) for liver, 434 (6.3%) for heart, and 215 (3.1%) for lung. As expected, demographic and clinical characteristics showed considerable variability among organ settings. Although the triple therapy in terms of CNI + antimet/mTOR + steroids was widely dispensed for all settings (63.7% for kidney, 33.5% for liver, 53.3% for heart, and 63.7% for lung), differences in the active agents involved were detected. The CESIT network represents a great opportunity to study several aspects related to the use, safety, and effectiveness of post-transplant maintenance immunosuppressive therapy in real practice.

Impact of acute kidney injury on graft outcomes of deceased donor kidney transplantation: A nationwide registry-based matched cohort study in Korea

BACKGROUND

Favorable long-term and short-term graft survival and patient survival after kidney transplantation (KT) from deceased donors with acute kidney injury (AKI) have been reported. However, few studies have evaluated effects of donor AKI status on graft outcomes after KT in Asian population. Thus, the purpose of this study was to evaluate graft function after KTs from donors with AKI compared to matched KTs from donors without AKI using a multicenter cohort in Korea.

METHODS

We analyzed a total of 1,466 KTs collected in Korean Organ Transplant Registry between April 2014 and December 2017. KTs from AKI donors (defined as donors with serum creatinine level ≥ 2 mg/dL) and non-AKI donors (275 cases for each group) were enrolled using a 1:1 propensity score matching. Graft outcomes including graft and patient survival, delayed graft function (DGF), rejection rate, and serially measured estimated glomerular filtration rate (eGFR) were evaluated.

RESULTS

After propensity matching, KTs from AKI donors showed higher rate of DGF (44.7% vs. 24.0%, p < 0.001). However, the rejection rate was not significantly different between the two groups (KTs from AKI donors vs. KTs from non-AKI donors). eGFRs measured after 6 months, 1 year, 2 years and 3 years were not significantly different by donor AKI status. With median follow-up duration of 3.52 years, cox proportional hazards models revealed hazard ratio of 0.973 (95% confidence interval [CI], 0.584 to 1.621), 1.004 (95% CI, 0.491 to 2.054) and 0.808 (95% confidence interval [CI], 0.426 to 1.532) for overall graft failure, death-censored graft failure and patient mortality, respectively, in KTs from AKI donors compared to KTs from non-AKI donors as a reference.

CONCLUSIONS

KTs from AKI donors showed comparable outcomes to KTs from non-AKI donors, despite a higher incidence of DGF. Results of this study supports the validity of using kidneys from deceased AKI donors in Asian population.

Outcomes of kidney transplantation over a 16-year period in Korea: An analysis of the National Health Information Database

BACKGROUND

This study investigated the outcomes of kidney transplantation (KT) over a 16-year period in Korea and identified risk factors for graft failure using a nationwide population-based cohort.

METHODS

We investigated the Korean National Health Insurance Service-National Health Information Database. Health insurance claims for patients who underwent KT between 2002 and 2017 were analyzed.

RESULTS

The data from 18,331 patients who underwent their first KT were reviewed. The percentage of antithymocyte globulin (ATG) induction continuously increased from 2.0% in 2002 to 23.5% in 2017. Rituximab began to be used in 2008 and had increased to 141 patients (9.6%) in 2013. Acute rejection occurred in 17.3% of all patients in 2002 but decreased to 6.3% in 2017. The rejection-free survival rates were 78.8% at 6 months after KT, 76.1% after 1 year, 67.5% after 5 years, 61.7% after 10 years, and 56.7% after 15 years. The graft survival rates remained over 80% until 12 years after KT, and then rapidly decreased to 50.5% at 16 years after KT. In Cox's multivariate analysis, risk factors for graft failure included being male, more recent KT, KT from deceased donor, use of ATG, basiliximab, or rituximab, tacrolimus use as an initial calcineurin inhibitor, acute rejection history, and cytomegalovirus infection.

CONCLUSIONS

ATG and rituximab use has gradually increased in Korea and more recent KT is associated with an increased risk of graft failure. Therefore, meticulous preoperative evaluation and postoperative management are necessary in the case of recent KT with high risk of graft failure.

Incidence of malignancy and related mortality after kidney transplantation: a nationwide, population-based cohort study in Korea

Post-transplant malignancy (PTM) is a leading cause of premature mortality among kidney transplantation recipients. However, population-based cohort studies that cover incidence, mortality, and risk factors for PTM are rarely reported, especially in East Asia. We designed a retrospective cohort study using a national population-based database. A total of 9915 kidney recipients between 2003 and 2016 were included. During this period, 598 cases (6.0%) of de novo PTM occurred. The most common PTM was thyroid cancer (14.2%), followed by colorectal (11.2%), kidney (10.7%), and stomach cancers (8.9%). The standardised incidence ratio for all-site cancer was 3.9. The risks of Kaposi sarcoma (192.9) and kidney cancer (21.1) were more than 10 times those of the general population. Cancer-related deaths were 89 (14.9%) with liver cancer being the highest (14.6%), followed by lung cancer (13.5%), non-Hodgkin lymphoma (NHL) (12.4%), stomach cancer (9.0%), and colorectal cancer (7.9%). The standardised mortality ratio (SMR) was slightly elevated (1.4). A notable increase in SMR was observed for lymphoma (9.3 for Hodgkin lymphoma and 5.5 for NHL). Older age and graft failure were significantly related to PTM. These findings reflecting geographical variation have implications for the development of strategies for fatal cancers to prevent premature deaths from PTM.

The risk factors associated with treatment-related mortality in 16,073 kidney transplantation-A nationwide cohort study

Mortality at an early stage after kidney transplantation is a catastrophic event. Treatment-related mortality (TRM) within 1 or 3 months after kidney transplantation has been seldom reported. We designed a retrospective observational cohort study using a national population-based database, which included information about all kidney recipients between 2003 and 2016. A total of 16,073 patients who underwent kidney transplantation were included. The mortality rates 1 month (early TRM) and 3 months (TRM) after transplantation were 0.5% (n = 74) and 1.0% (n = 160), respectively. Based on a multivariate analysis, older age (hazard ratio [HR] = 1.06; P < 0.001), coronary artery disease (HR = 3.02; P = 0.002), and hemodialysis compared with pre-emptive kidney transplantation (HR = 2.53; P = 0.046) were the risk factors for early TRM. Older age (HR = 1.07; P < 0.001), coronary artery disease (HR = 2.88; P < 0.001), and hemodialysis (HR = 2.35; P = 0.004) were the common independent risk factors for TRM. In contrast, cardiac arrhythmia (HR = 1.98; P = 0.027) was associated only with early TRM, and fungal infection (HR = 2.61; P < 0.001), and epoch of transplantation (HR = 0.34; P < 0.001) were the factors associated with only TRM. The identified risk factors should be considered in patient counselling, selection, and management to prevent TRM.

The safety, immunological benefits, and efficacy of ginseng in organ transplantation

Korean ginseng (Panax ginseng) is associated with a variety of therapeutic effects, including antioxidative, anti-inflammatory, vasorelaxative, antiallergic, antidiabetic, and anticancer effects. Accordingly, the use of ginseng has reached an all-time high among members of the general public. However, the safety and efficacy of ginseng in transplant recipients receiving immunosuppressant drugs have still not been elucidated. Transplantation is the most challenging and complex of surgical procedures and may require causation for the use of ginseng. In this regard, we have previously examined the safety, immunological benefits, and protective mechanisms of ginseng with respect to calcineurin inhibitor-based immunosuppression, which is the most widely used regimen in organ transplantation. Using an experimental model of calcineurin inhibitor-induced organ injury, we found that ginseng does not affect drug levels in the peripheral blood and tissue, favorably regulates immune response, and protects against calcineurin inhibitor-induced nephrotoxicity and pancreatic islet injury. On the basis of our experimental studies and a review of the related literature, we propose that ginseng may provide benefits in organ transplant recipients administered calcineurin inhibitors. Through the present review, we aimed to briefly discuss our current understanding of the therapeutic benefits of ginseng related to transplant patient survival.

Utility and safety of early allograft biopsy in adult deceased donor kidney transplant recipients

INTRODUCTION

Delayed graft function (DGF) is considered a risk factor for rejection after kidney transplantation (KTx). Clinical guidelines recommend weekly allograft biopsy until DGF resolves. However, who may benefit the most from such an aggressive policy and when histology should be evaluated remain debated.

METHODS

We analyzed 223 biopsies in 145 deceased donor KTx treated with basiliximab or anti-thymocyte globulin (rATG) and calcineurin inhibitor-based maintenance. The aim of the study was to assess the utility and safety of biopsies performed within 28 days of transplant. Relationships between transplant characteristics, indication, timing, and biopsy-related outcomes were evaluated.

RESULTS

Main indication for biopsy was DGF (87.8%) followed by lack of improvement in graft function (9.2%), and worsening graft function (3.1%). Acute tubular necrosis was the leading diagnosis (89.8%) whereas rejection was detected in 8.2% specimens. Rejection was more frequent in patients biopsied due to worsening graft function or lack of improvement in graft function than DGF (66.7% vs. 3.5%; P = 0.0075 and 33.3% vs. 3.5%; P = 0.0104, respectively) and in biopsies performed between day 15 and 28 than from day 0 to 14 (31.2% vs. 3.7%; P = 0.0002). Complication rate was 4.1%. Management was affected by the information gained with histology in 12.2% cases (7% considering DGF).

CONCLUSIONS

In low-immunological risk recipients treated with induction and calcineurin inhibitors maintenance, protocol biopsies obtained within 2 weeks of surgery to rule out rejection during DGF do not necessarily offer a favourable balance between risks and benefits. In these patients, a tailored approach may minimize complications thus optimizing results.

Long-term Clinical Significance of Tacrolimus Trough Level at the Early Period After Kidney Transplantation

BACKGROUND

The stable immunosuppressant level at the early period after kidney transplantation (KT) is one of the most important factors for the prognosis of KT. However, the extent of immunosuppression varies according to the policies of each KT center. We investigated the relationship between the clinical outcome and tacrolimus trough level (TTL) at the early post-transplant period.

MATERIALS AND METHODS

We retrospectively analyzed medical records of patients who underwent KT between July 2007 and June 2016. We investigated TTLs at 3 months after KT. We evaluated the incidence of biopsy-proven acute rejection (BPAR), cytomegalovirus infection, and graft survival according to the TTLs.

RESULTS

A total of 426 patients who received KT during the study period were enrolled. The mean age of KT recipients was 46.3 ± 11.5 years, and 55.5% of patients were men. The incidence of BPAR within 1 year after KT was significantly higher when TTLs at 3 months were less than 4.0 ng/mL (P = .020). Death-censored graft survival rates were significantly lower in KT recipients with BPAR and TTL less than 4.0 ng/mL (P < .001, P < .001, respectively). In multivariate analysis, BPAR and TTL less than 4.0 ng/mL at 3 months after KT were independent risk factors for graft failure.

CONCLUSION

BPAR and TTL less than 4.0 ng/mL at 3 months after KT are important risk factors for allograft failure. Therefore, TTL should be kept at least 4.0 ng/mL or more at 3 months after KT to reduce the incidence of BPAR within 1 year after KT.

Clinical Significance of Mycophenolate Mofetil Withdrawal in Kidney Transplant Recipients

INTRODUCTION

The most effective immunosuppressant protocol in kidney transplantation (KT) is the combination of a calcineurin inhibitor, steroid, and mycophenolate mofetil (MMF) until now. However, MMF withdrawal (MW) is performed for many reasons, and the clinical course of the KT recipients after MW is not clearly known. The purpose of this study was to investigate the clinical outcomes of KT after MW.

MATERIALS AND METHODS

We retrospectively analyzed the medical records of 626 KT recipients between 2000 and 2016. We evaluated the incidence of biopsy-proven acute rejection (BPAR), graft and patient survival rates, and risk factors related with graft failure.

RESULTS

The proportion of MW was 33.2% (208 of 626 patients). The median time between KT and MW was 6.4 months (range, 3.2-32.1 months). The common causes of MW were infection (70.7%), hematologic abnormalities (9.1%), and gastrointestinal trouble (7.7%). The incidence of BPAR was significantly higher in the MW group compared with the MMF continuation group (27.4% vs 8.9%, respectively, P < .001). Death-censored graft survival and patient survival rates were significantly lower in the MW group compared with the MMF continuation group (P < .001; P < .001, respectively). In the multivariate analysis, BPAR after MW was an independent risk factor for graft failure (hazard ratio 6.058, 95% confidence interval, 3.172-11.569, P < .001).

CONCLUSIONS

The incidence of rejection, graft failure, and patient mortality in KT were high after MW. Therefore, MW should be considered carefully.

Can the Toll-like receptors 4 expression in peripheral blood mononuclear cells help assess the effectiveness of immunosuppression and the chance of a future good renal transplant function?

BACKGROUND

A small percentage of peripheral blood mononuclear cells (PBMCs) circulating during the kidney transplantation (KT) period remain in the blood long after transplantation. A part of the PBMCs penetrates the graft.

AIM

To examine if the choice of immunosuppression may change TLR4ex and how TLR4ex affects the transplant function in the future.

MATERIAL

The study population-143 transplanted patients (pts) (55 females, 88 males), mean age on recruitment day 50.33 ± 12.8 years old, mean BMI 25.04 ± 4.18. 41 pts. experienced delayed graft function (DGF+). 55 pts. were treated with cyclosporine A (CsA) and 88 with tacrolimus (Tac). All were treated with mofetil mycophenolate (MMF). The PBMCs acquisition and starting point of the follow-up (TLR-day) was at least one month after KT.

METHOD

We investigated averaged mRNA expression of Toll-like receptors 4 (TLR4ex) in non-stimulated peripheral blood mononuclear cells with the use of real-time polymerase chain reaction. The KT pts. (All, Tac, CsA, DGF+) were divided by the respective median of their TLR4ex (lower: L-TLR4ex, higher: H-TLR4ex). Main clinical parameters and transplant biopsy files (if available) were assessed on TLR-day and post follow-up.

RESULTS

We found that TLR4ex was reduced for a long time in patients who experienced delayed graft function. L-TLR4ex had a higher proportion of DGF+ patients, and patients treated with CsA but lower of those treated with Tac than in H-TLR4ex. The amplitude of changes in renal function parameters (ΔEGFR%/ΔsCr/ΔsCr%) was clearly less favorable for L-TLR4ex. Tacrolimus expressed a stabilizing effect. Both the positive vasculitis score and chronic graft nephropathy were more frequent in the L-TLR4ex group. On TLR-day an association of renal function and Tac concentration with TLR4ex was clear only in the tacrolimus population. The TLR4ex was lower in patients with a future deterioration of the graft function.

CONCLUSION

In kidney transplant recipients the occurrence of DGF results in a long-term reduction of the averaged TLR4ex in PBMC. Tacrolimus exerts a clear, stabilizing, positive and dose-dependent effect on TLR4ex. An improvement in renal transplant function may be expected in KT patients with high TLR4ex. Evaluation of the averaged TLR4ex can be used to assess the efficacy of immunosuppression in the treatment with tacrolimus and to estimate the likelihood of deterioration in renal function.