The Implications of Acute Rejection and Reduced Allograft Function on Health Care Expenditures in Contemporary US Kidney Transplantation

Economic and humanistic burden in kidney transplant rejection: a literature review

INTRODUCTION

Antibody-mediated rejection (ABMR) is a major cause of late kidney allograft failure, but its economic and humanistic impacts have not been well-characterized in the literature.

AREAS COVERED

We reviewed available literature on economic burden (costs and healthcare resource use) and humanistic burden (health-related quality of life impacts [HRQOL] and utility estimates) in patients diagnosed with kidney transplant rejection; ABMR-specific studies were of particular interest. In total, 21 publications reporting economic and humanistic burden were included in the review; 9 of these reported ABMR-specific outcomes. The reviewed studies consistently showed a greater burden associated with ABMR-related transplant rejection than with non-ABMR transplant rejection.

EXPERT OPINION

Evidence suggests greater economic burden and increased HRQOL impairment with ABMR-related kidney transplant rejection relative to non-ABMR, although small sample sizes and missing definitions for ABMR make meaningful comparisons between studies challenging. Because no International Classification of Diseases (ICD)-10 codes currently describe the etiologies of transplant rejection, it is difficult to characterize the burden of distinct types of transplant rejection. The paucity of high-quality data on the burden of ABMR in kidney transplant rejection demonstrates the need for more etiology-centric ICD-10 codes.

Economic Evaluation in Kidney Transplantation: A Scoping Review and Novel PESTLE Stakeholder Gaps Analysis

AIM

The objective of this study was to systematically review the literature related to the economic evaluation of kidney transplantation to determine the extent of current research and identify gaps for future research.

SUBJECT AND METHODS

We searched 4 medical and 2 economic electronic databases as well as hand-searching reference lists of review articles and other pertinent articles. Exclusion criteria included articles that did not include original work (ie, reviews), were not in English, and were not journal articles or economic working papers (eg, commentaries, theses, abstracts). Full-text data abstraction included qualitative and quantitative parameters with the intent to perform a gap analysis for future research.

RESULTS

A total of 299 articles were included and spanned a 48-year period from 1968 to 2016, with >73% published in 2000 or after. The most common topics included immunosuppression drugs, dialysis vs kidney transplantation, organ allocation, and the potential market for donor organs. Most articles were from the United States and originated from 73 medical journals and 34 economic journals or working paper centers. There were 58 articles dealing with costing, 153 using cost-effectiveness, 69 using economic modeling, 6 performing systematic reviews with meta-analyses, and 13 exploring the qualitative financial environment of individuals and the economy.

CONCLUSIONS

Research gaps were identified in every parameter used to evaluate the studies, and a new system of gap analysis for scoping reviews was also proposed.

Kidney Transplantation, Immunosuppression and the Risk of Fracture: Clinical and Economic Implications

Rationale & Objective

Disorders of bone and mineral metabolism frequently develop with advanced kidney disease, may be exacerbated by immunosuppression after kidney transplantation, and increase the risk of fractures.

Study Design

Retrospective database study.

Setting & Participants

Kidney-only transplant recipients aged ≥18 years from 2005 to 2016 in the United States captured in US Renal Data System records, which integrate Organ Procurement and Transplantation Network/United Network for Organ Sharing records with Medicare billing claims.

Exposures

Various immunosuppression regimens in the first 3 months after kidney transplantation.

Outcomes

The development of fractures, as ascertained using diagnostic codes on Medicare billing claims.

Analytical Approach

We used multivariable Cox regression with inverse propensity weighting to compare the incidence of fractures >3 months-to-3 years after kidney transplantation associated with various immunosuppression regimens compared to a reference regimen of antithymocyte globulin (TMG) or alemtuzumab (ALEM) with tacrolimus + mycophenolic acid + prednisone using inverse probability treatment weighting.

Results

Overall, fractures were identified in 7.5% of kidney transplant recipients (women, 8.8%; men, 6.7%; age < 55 years, 5.9%; age ≥ 55 years, 9.3%). In time-varying regression, experiencing a fracture was associated with a substantially increased risk of subsequent death within 3 months (adjusted hazard ratio [aHR], 3.06; 95% confidence interval [CI], 2.45-3.81). Fractures were also associated with increased Medicare spending (first year: $5,122; second year: $10,890; third year: $11,083; [P < 0.001]). Induction with TMG or ALEM and the avoidance or early withdrawal of steroids significantly reduced the risk of fractures in younger (aHR, 0.63; 95% CI, 0.54-0.73) and older (aHR, 0.83; 95% CI, 0.74-0.94) patients. The avoidance or early withdrawal of steroids with any induction was associated with a reduced risk of fractures in women.

Limitations

This was a retrospective study which lacked data on immunosuppression levels.

Conclusions

Fractures after kidney transplantation are associated with significantly increased mortality risk and costs. The early avoidance or early withdrawal of steroids after induction with TMG or ALEM reduces the risk of fractures after kidney transplantation and should be considered for patients at high-risk of this complication, including older adults and women.

Costs in the Year Following Deceased Donor Kidney Transplantation: Relationships With Renal Function and Graft Failure

Relationships between renal function and medical costs for deceased donor kidney transplant recipients are not fully quantified post-transplant. We describe these relationships with renal function measured by estimated glomerular filtration rate (eGFR) and graft failure. The United States Renal Data System identified adults receiving single-organ deceased donor kidneys 2012–2015. Inpatient, outpatient, other facility costs and eGFRs at discharge, 6 and 12 months were included. A time-history of costs was constructed for graft failures and monthly costs in the first year post-transplant were compared to those without failure. The cohort of 24,021 deceased donor recipients had a 2.4% graft failure rate in the first year. Total medical costs exhibit strong trends with eGFR. Recipients with 6-month eGFRs of 30–59 ml/min/1.73m² have total costs 48% lower than those <30 ml/min/1.73m². For recipients with graft failure monthly costs begin to rise 3–4 months prior to failure, with incremental costs of over $38,000 during the month of failure. Mean annual total incremental costs of graft failure are over $150,000. Total costs post-transplant are strongly correlated with eGFR. Graft failure in the first year is an expensive, months-long process. Further reductions in early graft failures could yield significant human and economic benefits.

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.

Perioperative blood usage and therapeutic plasma exchange in kidney transplantation during a 16-year period in South Korea

BACKGROUND

The frequency of kidney transplantation (KT) is increasing. Blood transfusion plays an important role in the success of KT. Therapeutic plasma exchange (TPE) is also used for desensitisation in ABO-incompatible KT and treatment of antibody-mediated rejection.

MATERIALS AND METHODS

We analysed red blood cell (RBC), platelet, and fresh frozen plasma (FFP) usage and the number of TPE procedures performed during the hospitalisation of KT patients from 2002 to 2017 using the Korean National Health Insurance Service-National Health Information Database.

RESULTS

A total of 18,331 KT patients were included in this study. The number of transfused RBCs continued to increase from 4,806 units in 2002-2005 to 12,390 units in 2014-2017. However, the average number of RBCs transfused per patient decreased from 2.17 to 1.79 units. Estimated platelet usage increased from 4,259 units in 2002-2005 to 11,519 units in 2014-2017, and the proportion of filtered platelets increased from 72.6% to 83.4% during the same period. There was a huge increase in the total number of FFP units used, from 2,255 units in 2002-2005 to 51,531 units in 2014-2017. The number of TPE procedures performed also increased from 296 to 6,479 during the same period. Patients with acute rejection accounted for 8.8% of all KT patients, and more RBC and FFP were used for these patients and a greater number of TPE procedures were performed compared to those who did not experience rejection.

DISCUSSION

Blood usage and TPE have increased steadily with the increasing numbers of KTs. Therefore, continuous efforts are needed to ensure appropriate perioperative blood preparation and usage for KT patients.

Economic impacts of alternative kidney transplant immunosuppression: A national cohort study

Understanding the economic implications of induction and maintenance immunosuppression (ISx) is important in developing personalized kidney transplant (KTx) care. Using data from a novel integrated data set including financial records from the University Health System Consortium, Medicare, and pharmacy claims (2007-2014), we estimated the differences in the impact of induction and maintenance ISx regimens on transplant hospitalization costs and Medicare payments from KTx to 3 years. Use of thymoglobulin (TMG) significantly increased transplant hospitalization costs ($12 006; P = .02), compared with alemtuzumab and basiliximab. TMG resulted in lower Medicare payments in posttransplant years 1 (-$2058; P = .05) and 2 (-$1784; P = .048). Patients on steroid-sparing ISx incurred relatively lower total Medicare spending (-$10 880; P = .01) compared with patients on triple therapy (tacrolimus, antimetabolite, and steroids). MPA/AZA-sparing, mammalian target of rapamycin inhibitors-based, and cyclosporine-based maintenance ISx regimens were associated with significantly higher payments. Alternative ISx regimens were associated with different KTx hospitalization costs and longer-term payments. Future studies of clinical efficacy should also consider cost impacts to define the economic effectiveness of alternative ISx regimens.

Long-Term Outcomes after Acute Rejection in Kidney Transplant Recipients: An ANZDATA Analysis

BACKGROUND

Declining rates of acute rejection (AR) and the high rate of 1-year graft survival among patients with AR have prompted re-examination of AR as an outcome in the clinic and in trials. Yet AR and its treatment may directly or indirectly affect longer-term outcomes for kidney transplant recipients.

METHODS

To understand the long-term effect of AR on outcomes, we analyzed data from the Australia and New Zealand Dialysis and Transplant Registry, including 13,614 recipients of a primary kidney-only transplant between 1997 and 2017 with at least 6 months of graft function. The associations between AR within 6 months post-transplant and subsequent cause-specific graft loss and death were determined using Cox models adjusted for baseline donor, recipient, and transplant characteristics.

RESULTS

AR occurred in 2906 recipients (21.4%) and was associated with graft loss attributed to chronic allograft nephropathy (hazard ratio [HR], 1.39; 95% confidence interval [95% CI], 1.23 to 1.56) and recurrent AR beyond month 6 (HR, 1.85; 95% CI, 1.39 to 2.46). Early AR was also associated with death with a functioning graft (HR, 1.22; 95% CI, 1.08 to 1.36), and with death due to cardiovascular disease (HR, 1.30; 95% CI, 1.11 to 1.53) and cancer (HR, 1.35; 95% CI, 1.12 to 1.64). Sensitivity analyses restricted to subgroups with either biopsy-proven, antibody-mediated, or vascular rejection, or stratified by treatment response produced similar results.

CONCLUSIONS

AR is associated with increased risks of longer-term graft failure and death, particularly death from cardiovascular disease and cancer. The results suggest AR remains an important short-term outcome to monitor in kidney transplantation and clinical trials.

Peritransplant VLA-4 blockade inhibits endogenous memory CD8 T cell infiltration into high-risk cardiac allografts and CTLA-4Ig resistant rejection

Recipient endogenous memory CD8 T cells expressing reactivity to donor class I MHC infiltrate MHC-mismatched cardiac allografts within 24 hours after reperfusion and express effector functions mediating graft injury. The current study tested the efficacy of Very Late Antigen-4 (VLA-4) blockade to inhibit endogenous memory CD8 T cell infiltration into cardiac allografts and attenuate early posttransplant inflammation. Peritransplant anti-VLA-4 mAb given to C57BL6 (H-2b ) recipients of AJ (H-2a ) heart allografts completely inhibited endogenous memory CD4 and CD8 T cell infiltration with significant decrease in macrophage, but not neutrophil, infiltration into allografts subjected to either minimal or prolonged cold ischemic storage (CIS) prior to transplant, reduced intra-allograft IFN-γ-induced gene expression and prolonged survival of allografts subjected to prolonged CIS in CTLA-4Ig treated recipients. Anti-VLA-4 mAb also inhibited priming of donor-specific T cells producing IFN-γ until at least day 7 posttransplant. Peritransplant anti-VLA plus anti-CD154 mAb treatment similarly prolonged survival of allografts subjected to minimal or increased CIS prior to transplant. Overall, these data indicate that peritransplant anti-VLA-4 mAb inhibits early infiltration memory CD8 T cell infiltration into allografts with a marked reduction in early graft inflammation suggesting an effective strategy to attenuate negative effects of heterologous alloimmunity in recipients of higher risk grafts.

Cost-effectiveness of hepatitis C-positive donor kidney transplantation for hepatitis C-negative recipients with concomitant direct-acting antiviral therapy

Pilot studies suggest that transplanting hepatitis C virus (HCV)-positive donor (D+) kidneys into HCV-negative renal transplant (RT) recipients (R-), then treating HCV with direct-acting antivirals (DAA) is clinically feasible. To determine whether this is a cost-effective approach, a decision tree model was developed to analyze costs and effectiveness over a 5-year time frame between 2 choices: RT using a D+/R- strategy compared to continuing dialysis and waiting for a HCV-negative donor (D-/R-). The strategy of accepting a HCV+ organ then treating HCV was slightly more effective and substantially less expensive and resulted in an expected 4.8 years of life (YOL) with a cost of ≈$138 000 compared to an expected 4.7 YOL with a cost of ≈$329 000 for the D-/R- strategy. The D+/R- strategy remained dominant after sensitivity analyses including the difference in RT death probabilities or acute rejection probabilities between using D+ vs D- kidney; time that D-/R- patients waited for RT; dialysis death probabilities while waitlisted for RT in the D-/R- strategy; DAA therapy expected cure rate; costs of transplant, immunosuppressives, DAA therapy, dialysis, or acute rejection. The D+/R- strategy followed by treatment with DAA is less costly and slightly more effective compared to the D-/R- strategy.

Metformin use in the first year after kidney transplant, correlates, and associated outcomes in diabetic transplant recipients: A retrospective analysis of integrated registry and pharmacy claims data

While guidelines support metformin as a therapeutic option for diabetic patients with mild-to-moderate renal insufficiency, the frequency and outcomes of metformin use in kidney transplant recipients are not well described. We integrated national U.S. transplant registry data with records from a large pharmaceutical claims clearinghouse (2008-2015). Associations (adjusted hazard ratio, 95% LCL aHR95% UCL ) of diabetes regimens (with and excluding metformin) in the first year post-transplant with patient and graft survival over the subsequent year were quantified by multivariate Cox regression, adjusted for recipient, donor, and transplant factors and propensity for metformin use. Among 14 144 recipients with pretransplant type 2 diabetes mellitus, 4.7% filled metformin in the first year post-transplant; most also received diabetes comedications. Compared to those who received insulin-based regimens without metformin, patients who received metformin were more likely to be female, have higher estimated glomerular filtration rates, and have undergone transplant more recently. Metformin-based regimens were associated with significantly lower adjusted all-cause (aHR 0.18 0.410.91 ), malignancy-related (aHR 0.45 0.450.99 ), and infection-related (aHR 0.12 0.320.85 ) mortality, and nonsignificant trends toward lower cardiovascular mortality, graft failure, and acute rejection. No evidence of increased adverse graft or patient outcomes was noted. Use of metformin-based diabetes treatment regimens may be safe in carefully selected kidney transplant recipients.

Predicting Health Care Utilization and Charges Using a Risk Score for Poor Adherence in Pediatric Kidney Transplant Recipients

Pediatric kidney transplant recipients must follow a complicated regimen of timely adherence to immunosuppressant medication, routine blood work, and medical follow-up visits. Failure to adhere to the recommended regimen can result in medical complications and costly treatment. We developed a novel risk score to identify patients at risk for poor adherence behaviors and evaluated whether it would predict future health care utilization and charges. Our risk stratification score combined three simple pass/fail metrics of adherence derived directly from the electronic health record including standard deviation of immunosuppression drug levels, timely laboratory monitoring, and timely clinic visits as indicated by our clinical protocol. Risk for poor adherence was assessed over a three-month period. Linear regression was used to predict subsequent health care charges and utilization. Greater than 75% of patients had some degree of nonadherence risk during the study period, but there were no significant differences found on any outcomes for the overall score. However, when the individual components of the overall risk score were evaluated independently, patients with tacrolimus drug level standard deviation ≥2 (e.g., a marker of poor adherence) had greater health care utilization (e.g., hospitalizations) and increased total charges. Additionally, patients who did not follow up in clinic at least every 4 months had more ED visits and ED-related charges, but fewer hospitalizations. Regular clinic visits and minimizing drug level variation may deter future costly ED visits and hospitalizations.

Posttransplant Medical Adherence: What Have We Learned and Can We Do Better?

Purpose of review

Non-adherence to the medical regimen after kidney transplantation can contribute to poor clinical outcomes, and strategies to maximize adherence are sought by care providers and patients alike. We assessed recent evidence on prevalence, risk factors, and clinical outcomes associated with non-adherence to the medical regimen after kidney transplantation. We summarized recent clinical trials testing interventions to improve adherence and generated recommendations for future research and clinical practice.

Recent findings

A large evidence base documents rates of non-adherence to each of the multiple components of the regimen, including medication-taking, lifestyle activities, clinical care requirements, and substance use restrictions. Some risk factors for non-adherence are well known but the full range of risk factors remains unclear. Non-adherence to immunosuppressants and to other components of the regimen increases morbidity and mortality risks. Recent interventions, including education and counseling; electronic health strategies; and medication dose modifications, show promise for reducing immunosuppressant non-adherence. However, most of these interventions would be difficult to deploy in everyday clinical practice. Systematic dissemination of efficacious interventions into clinical practice has not been undertaken.

Summary

Rates and risk factors for non-adherence to the medical regimen have been examined and there is evidence that non-adherence may be ameliorated by a range of interventions. Although gaps in the evidence base remain, it would be timely to devote greater efforts to dissemination of findings. Thus, efforts are needed to assist transplant programs in using existing evidence to better identify patients who are non-adherent and to design and implement strategies to reduce or prevent non-adherence.

Clinical and Economic Consequences of Early Cancer After Kidney Transplantation in Contemporary Practice

BACKGROUND

Current clinical and economic consequences of cancer after kidney transplantation are incompletely defined.

METHODS

We examined United States Renal Data System records of Medicare-insured kidney transplant recipients in 2000 to 2011 to determine clinical and economic impacts of cancer diagnosed within the first 3 years posttransplantation. Cancer diagnoses were identified using Medicare billing codes and categorized as nonmelanoma skin cancer (NMSC), viral-linked and "other" cancers. Associations of cancers with mortality and graft loss were estimated by time-varying Cox regression. Impacts of cancer diagnoses on inpatient and outpatient costs within each year were quantified by multivariate linear regression modeling.

RESULTS

Among 67 157 recipients, by 3 years posttransplant, NMSC was diagnosed in 5.7%, viral-linked cancer in 1.9%, and "other" cancers in 6.3%. Viral-linked cancer was associated with more than 3-fold increased risk in subsequent mortality until the third transplant anniversary, and nearly twice the mortality risk after year 3. "Other" cancers had similar associations with death and graft loss, whereas NMSC was associated with 33% higher mortality beyond the third year posttransplant. Viral-linked cancer had the largest inpatient and outpatient cost impacts per case, followed by "other" cancer, whereas NMSC impacted only outpatient costs. Care of new cancer diagnoses was generally more costly than care of previously established diagnoses. Cancer accounted for 3% to 5.5% of total inpatient Medicare expenditures and 1.5% to 3.3% of outpatient expenditures in the first 3 years posttransplant.

CONCLUSIONS

Early posttransplant malignancy is an expensive and morbid condition that warrants attention in efforts to improve pretransplant screening and management protocols before and after transplant.

Decreasing Estimated Glomerular Filtration Rate Is Associated With Increased Risk of Hospitalization After Kidney Transplantation

INTRODUCTION

Following renal transplantation, decreased renal function is associated with increased risk of cardiovascular disease, graft loss and mortality. We investigated whether declining renal function was associated with hospitalization post-transplant.

METHODS

Adult, first-time, kidney transplant recipients between 2004 and 2006 from the United Network for Organ Sharing database and hospitalizations one year after the 6-month post-transplant follow-up visit were examined. Generalized linear models explored the relationship between estimated glomerular filtration rate (eGFR) measured at 6 months and the number of hospitalizations in the following year.

RESULTS

Of 15,778 kidney transplant recipients, 19.1% were admitted in the year after the 6-month follow-up visit. Among those hospitalized, the mean number of hospitalizations was 1.71 and increased with decreasing eGFR. In multivariable models, a decrease in eGFR was significantly associated with increased hospitalizations: for every 10 ml/min/1.73m² decrease in eGFR, there was an 11% increase in hospitalization rate (p <0.001). Lower eGFR after the first 6 months following transplantation was associated with an increase in late hospitalizations among adult kidney transplant recipients.

DISCUSSION

Identifying patients with declining eGFR and other risk factors may help prevent morbidity and mortality associated with hospitalization post-transplantation.

The Changing Financial Landscape of Renal Transplant Practice: A National Cohort Analysis

Kidney transplantation has become more resource intensive as recipient complexity has increased and average donor quality has diminished over time. A national retrospective cohort study was performed to assess the impact of kidney donor and recipient characteristics on transplant center cost (exclusive of organ acquisition) and Medicare reimbursement. Data from the national transplant registry, University HealthSystem Consortium hospital costs, and Medicare payments for deceased donor (N = 53 862) and living donor (N = 36 715) transplants from 2002 to 2013 were linked and analyzed using multivariate linear regression modeling. Deceased donor kidney transplant costs were correlated with recipient (Expected Post Transplant Survival Score, degree of allosensitization, obesity, cause of renal failure), donor (age, cause of death, donation after cardiac death, terminal creatinine), and transplant (histocompatibility matching) characteristics. Living donor costs rose sharply with higher degrees of allosensitization, and were also associated with obesity, cause of renal failure, recipient work status, and 0-ABDR mismatching. Analysis of Medicare payments for a subsample of 24 809 transplants demonstrated minimal correlation with patient and donor characteristics. In conclusion, the complexity in the landscape of kidney transplantation increases center costs, posing financial disincentives that may reduce organ utilization and limit access for higher-risk populations.

Profiling risk for acute rejection in kidney transplantation: recipient age is a robust risk factor

Careful management of immunosuppression is paramount to prevent acute rejection in kidney transplantation. We studied a cohort of 139,875 kidney transplant recipients from the Organ Procurement and Transplantation Network (OPTN) database between 2002 and 2013. We confirmed the analysis with a cohort of 35,277 who received thymoglobulin induction with tacrolimus maintenance, and a third cohort of 12,161 recipients who received basiliximab induction with tacrolimus maintenance. We performed multivariate logistic regression analyses on data from all three cohorts and identified independent risk factors for treated acute rejection at 1 year. Recipient age was a robust risk factor for rejection in all three cohorts in a dose response pattern. Young age (18-25 years) was among the strongest risk factors for rejection in all three cohorts; thymoglobulin cohort: OR 1.87 (1.59-2.19); basiliximab cohort: OR 2.41 (1.89-3.05); and inclusive cohort: OR 1.97 (1.83-2.12). The opposite was true for old age (65-69 years); thymoglobulin cohort: OR 0.69 (0.59-0.81); basiliximab cohort: OR 0.77 (0.62-0.96); and inclusive cohort: OR 0.75 (0.70-0.80). This study is unique because it is the largest and most comprehensive multivariate analysis that demonstrates recipient age is a robust risk factor for acute rejection in an inverse dose response pattern.

Differential risks for adverse outcomes 3 years after kidney transplantation based on initial immunosuppression regimen: a national study

We examined integrated national transplant registry, pharmacy fill, and medical claims data for Medicare-insured kidney transplant recipients in 2000-2011 (n = 45 164) from the United States Renal Data System to assess the efficacy and safety endpoints associated with seven early (first 90 days) immunosuppression (ISx) regimens. Risks of clinical complications over 3 years according to IS regimens were assessed with multivariate regression analysis, including the adjustment for covariates and propensity for receipt of a nonreference ISx regimen. Compared with the reference ISx (thymoglobulin induction with tacrolimus, mycophenolate, and prednisone maintenance), sirolimus-based ISx was associated with significantly higher three-year risks of pneumonia (adjusted hazard ratio, aHR 1.45; P < 0.0001), sepsis (aHR 1.40; P < 0.0001), diabetes (aHR 1.21; P < 0.0001), acute rejection (AR; adjusted odds ratio, aOR 1.33; P < 0.0001), graft failure (aHR 1.78; P < 0.0001), and patient death (aHR 1.40; P < 0.0001), but reduced skin cancer risk (aHR 0.71; P < 0.001). Cyclosporine-based IS was associated with increased risks of pneumonia (aHR 1.17; P < 0.001), sepsis (aHR 1.16; P < 0.001), AR (aOR 1.43; P < 0.001), and graft failure (aHR 1.39; P < 0.001), but less diabetes (aHR 0.83; P < 0.001). Steroid-free ISx was associated with the reduced risk of pneumonia (aHR 0.89; P = 0.002), sepsis (aHR 0.80; P < 0.001), and diabetes (aHR 0.77; P < 0.001), but higher graft failure (aHR 1.35; P < 0.001). Impacts of ISx over time warrant further study to better guide ISx tailoring to balance the efficacy and morbidity.

Dual antiplatelet and anticoagulant APAC prevents experimental ischemia-reperfusion-induced acute kidney injury

BACKGROUND

Renal ischemia-reperfusion predisposes to acute kidney injury (AKI) and mortality. APAC, mast cell heparin proteoglycan mimetic is a potent dual antiplatelet and anticoagulant inhibiting thrombosis in several vascular models.

METHODS

Clinically relevant (0.06 and 0.13 mg/kg) and high (0.32 and 7.3 mg/kg) heparin doses of APAC and unfractionated heparin (UFH) were administered i.v. in pharmacological studies. Antithrombotic action of APAC and UFH was assessed with platelet aggregation to collagen, activated partial thromboplastin (APTT) and prothrombin (PT) times. Pharmacodynamics of [⁶⁴Cu]-APAC or -UFH were monitored by PET/CT. Next, APAC and UFH doses (0.06 and 0.13 mg/kg) were i.v. administered 10 min prior to renal ischemia-reperfusion injury (IRI) in rats.

RESULTS

APAC in contrast to UFH inhibited platelet aggregation. During 0.06 and 0.13 mg/kg dose regimens APTT and PT remained at baseline, but at the high APTT prolonged fourfold to sixfold. Overall bio-distribution and clearance of APAC and UFH were similar. After bilateral 30-min renal artery clamping, creatinine, urea nitrogen and neutrophil gelatinase-associated lipocalin concentrations and histopathology indicated faster renal recovery by APAC (0.13 mg/kg). APAC, unlike UFH, prevented expression of innate immune ligand hyaluronan and tubulointerstitial injury marker Kim-1. Moreover, in severe bilateral 1-h renal artery clamping, APAC (0.13 mg/kg) prevented AKI, as demonstrated both by biomarkers and survival. Compatible with kidney protection APAC reduced the circulating levels of vascular destabilizing and pro-inflammatory angiopoietin-2 and syndecan-1. No tissue bleeding ensued.

CONCLUSION

APAC and UFH were similarly eliminated via kidneys and liver. In contrast to UFH, APAC (0.13 mg/kg) was reno-protective in moderate and even severe IRI by attenuating vascular injury and innate immune activation.

Economic Impacts of ABO-Incompatible Live Donor Kidney Transplantation: A National Study of Medicare-Insured Recipients

The infrequent use of ABO-incompatible (ABOi) kidney transplantation in the United States may reflect concern about the costs of necessary preconditioning and posttransplant care. Medicare data for 26 500 live donor kidney transplant recipients (2000 to March 2011), including 271 ABOi and 62 A2-incompatible (A2i) recipients, were analyzed to assess the impact of pretransplant, transplant episode and 3-year posttransplant costs. The marginal costs of ABOi and A2i versus ABO-compatible (ABOc) transplants were quantified by multivariate linear regression including adjustment for recipient, donor and transplant factors. Compared with ABOc transplantation, patient survival (93.2% vs. 88.15%, p = 0.0009) and death-censored graft survival (85.4% vs. 76.1%, p < 0.05) at 3 years were lower after ABOi transplant. The average overall cost of the transplant episode was significantly higher for ABOi ($65 080) compared with A2i ($36 752) and ABOc ($32 039) transplantation (p < 0.001), excluding organ acquisition. ABOi transplant was associated with high adjusted posttransplant spending (marginal costs compared to ABOc - year 1: $25 044; year 2: $10 496; year 3: $7307; p < 0.01). ABOi transplantation provides a clinically effective method to expand access to transplantation. Although more expensive, the modest increases in total spending are easily justified by avoiding long-term dialysis and its associated morbidity and cost.

Monitoring the Intracellular Tacrolimus Concentration in Kidney Transplant Recipients with Stable Graft Function

Although monitoring the intracellular concentration of immunosuppressive agents may be a promising approach to individualizing the therapy after organ transplantation, additional studies on this issue are needed prior to its clinical approval. We investigated the relationship between intracellular and whole blood concentrations of tacrolimus (IC-TAC and WB-TAC, respectively), the factors affecting this relationship, and the risk of rejection based upon IC-TAC in stable kidney recipients. Both IC-TAC and WB-TAC were measured simultaneously in 213 kidney recipients with stable graft function using LC-MS/MS. The tacrolimus ratio was defined as IC-TAC per WB-TAC. The genetic polymorphism of ABCB1 gene and flow cytometric analyses were conducted to probe the correlation between tacrolimus concentrations and the immunoreactivity status as a potential risk of rejection, respectively. The correlation between IC-TAC and WB-TAC was relatively linear (r = 0.67; P<0.001). The factors affecting the tacrolimus ratio were sex, hematocrit, and the transplant duration, as follows: a high tacrolimus ratio was noted in female patients, patients with a low hematocrit, and patients with a short transplant period. However, the tacrolimus ratio did not reflect the prior clinical outcomes (e.g., rejection) or the genetic polymorphism of ABCB1. After stimulation with phorbol-12-myristate 13-acetate and ionomycin, the proportion of T cells producing interferon-gamma or interleukin-2 was higher in the low-IC-TAC group than in the high-IC-TAC group. Further studies are required to evaluate the value of the intracellular tacrolimus concentrations in several clinical settings, such as rejection, infection, and drug toxicity.

Clinical and economic consequences of first-year urinary tract infections, sepsis, and pneumonia in contemporary kidney transplantation practice

We examined United States Renal Data System registry records for Medicare-insured kidney transplant recipients in 2000-2011 to study the clinical and cost impacts of urinary tract infections (UTI), pneumonia, and sepsis in the first year post-transplant among a contemporary, national cohort. Infections were identified by billing diagnostic codes. Among 60 702 recipients, 45% experienced at least one study infection in the first year post-transplant, including UTI in 32%, pneumonia in 13%, and sepsis in 12%. Older recipient age, female sex, diabetic kidney failure, nonstandard criteria organs, sirolimus-based immunosuppression, and steroids at discharge were associated with increased risk of first-year infections. By time-varying, multivariate Cox regression, all study infections predicted increased first-year mortality, ranging from 41% (aHR 1.41, 95% CI 1.25-1.56) for UTI alone, 6- to 12-fold risk for pneumonia or sepsis alone, to 34-fold risk (aHR 34.38, 95% CI 30.35-38.95) for those with all three infections. Infections also significantly increased first-year costs, from $17 691 (standard error (SE) $591) marginal cost increase for UTI alone, to approximately $40 000-$50 000 (SE $1054-1238) for pneumonia or sepsis alone, to $134 773 (SE $1876) for those with UTI, pneumonia, and sepsis. Clinical and economic impacts persisted in years 2-3 post-transplant. Early infections reflect important targets for management protocols to improve post-transplant outcomes and reduce costs of care.

Long-term safety and efficacy of antithymocyte globulin induction: use of integrated national registry data to achieve ten-year follow-up of 10-10 Study participants

Background

Rabbit antithymocyte globulin (rATG, Thymoglobulin®) is the most common induction immunosuppression therapy in kidney transplantation. We applied a database integration strategy to capture and compare long-term (10-year) outcome data for US participants in a clinical trial of rATG versus FDA-approved basiliximab.

Methods

Records for US participants in an international, 1-year, randomized clinical trial comparing rATG and basiliximab induction in deceased donor kidney transplantation were integrated with records from the US national Organ Procurement and Transplantation (OPTN) registry using center, transplant dates, recipient sex, and birthdates. The OPTN captures center-reported acute rejection, graft failure, death, and cancer events, and incorporates comprehensive death records from the Social Security Death Master File. Ten-year outcomes according to randomized induction regimen were compared by Kaplan–Meier analysis (two-sided P). Non-inferiority of rATG was assessed using a one-tailed equivalence test (a-priori equivalence margins of 0–10 %).

Results

Of 183 US trial participants, 89 % (n = 163) matched OPTN records exactly; the remainder were matched by extending agreement windows for transplant and birthdates. Matches were validated by donor and recipient blood types. By Kaplan–Meier analysis, 10 years post-transplant, freedom from acute rejection, graft failure, or death was 32.6 % and 24.0 % in the rATG and basiliximab arms, respectively (P = 0.09). The incidence of acute rejection with rATG versus basiliximab induction was 21.0 % versus 32.8 % (P = 0.07). Patient survival (52.5 % versus 52.2 %, P = 0.92) and graft survival (34.3 % versus 30.9 %, P = 0.56) rates were numerically and statistically similar for both arms. Comparison of the composite outcome meets non-inferiority criteria even with a 0 % equivalence margin (one-sided P = 0.04). With a 10 % equivalence margin, the odds that rATG is no worse than basiliximab for 10-year risk of the composite endpoint are >99 %.

Conclusions

Ten years post-transplant, rATG induction has comparable efficacy and safety to FDA-approved basiliximab. Integration of clinical trial records with national registry data can enable long-term monitoring of trial participants in transplantation, circumventing logistical and cost barriers of extended follow-up.

Trial registration

ClinicalTrials.gov NCT00235300

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0891-y) contains supplementary material, which is available to authorized users.

The Cost of Transplant Immunosuppressant Therapy: Is This Sustainable?

A solid organ transplant is life-saving therapy that engenders the use of immunosuppressive medications for the lifetime of the transplanted organ and its recipient. Conventional therapy includes both induction therapy (a biologic that is infused peri-operatively) followed by maintenance therapy. The cost of these medications is a constant concern and the advent of generics has brought this cost down modestly. For those lacking long term insurance coverage, this may be a significant out of pocket expense that is not affordable. Moreover, transplant Centers are managing higher risk transplant recipients that require more complex induction regimens and longer term use of such biologic agents in the context of desensitization or abrogation of de novo antibody mediated injury. While in kidney transplantation, Medicare part B covers three years of medication, there is frequent non-adherence due to cost after that time-point. The impact of the Affordable Care Act remains uncertain at this time. Finally the pipeline of new therapies is limited due to the cost of development of a drug, the inherent cost of clinical studies, and lack of defined endpoints for newer therapies in high risk patients. These new therapies are of high value to the community but will contribute additional burden to current drug costs.

Decision-making analysis for allergen immunotherapy versus nasal steroids in the treatment of nasal steroid-responsive allergic rhinitis

BACKGROUND

The purpose of the study was to determine the age at which initiation of specific subcutaneous immunotherapy (SCIT) becomes more cost-effective than continued lifetime intranasal steroid (NS) therapy in the treatment of allergic rhinitis, with the use of a decision analysis model.

METHODS

A Markov decision analysis model was created for this study. Economic analyses were performed to identify "break-even" points in the treatment of allergic rhinitis with the use of SCIT and NS. Efficacy rates for therapy and cost data were collected from the published literature. Models in which there was only incomplete improvement while receiving SCIT were also evaluated for economic break-even points. The primary perspective of the study was societal.

RESULTS

Multiple break-even point curves were obtained corresponding to various clinical scenarios. For patients with seasonal allergic rhinitis requiring NS (i.e., fluticasone) 6 months per year, the age at which initiation of SCIT provides long-term direct cost advantage is less than 41 years. For patients with perennial rhinitis symptoms requiring year-round NS, the cut-off age for SCIT cost-effectiveness increases to 60 years. Hypothetical subjects who require continued NS treatment (50% reduction of previous dosage) while receiving SCIT also display break-even points, whereby it is economically advantageous to consider allergy referral and SCIT, dependent on the cost of the NS prescribed.

CONCLUSION

The age at which SCIT provides economic advantages over NS in the treatment of allergic rhinitis depends on multiple clinical factors. Decision analysis models can assist the physician in accounting for these factors and customize patient counseling with regard to treatment options.

National assessment of early biliary complications after liver transplantation: economic implications

BACKGROUND

Despite improvement in surgical technique and medical management of liver transplant recipients, biliary complications remain a frequent cause of posttransplant morbidity and graft loss. Biliary complications require potentially expensive interventions including radiologic procedures and surgical revisions.

METHODS

A national data set linking transplant registry and Medicare claims data for 12,803 liver transplant recipients was developed to capture information on complications, treatments, and associated direct medical costs up to 3 years after transplantation.

RESULTS

Biliary complications were more common in recipients of donation after cardiac death compared to donation after brain death allografts (23% vs. 19% P<0.001). Among donation after brain death recipients, biliary complications were associated with $54,699 (95% confidence interval [CI], $49,102 to $60,295) of incremental spending in the first year after transplantation and $7,327 in years 2 and 3 (95% CI, $4,419-$10,236). Biliary complications in donation after cardiac death recipients independently increased spending by $94,093 (95% CI, $64,643-$124,542) in the first year and $12,012 (95% CI, $-1,991 to $26,016) in years 2 and 3.

CONCLUSION

This national study of biliary complications demonstrates the significant economic impact of this common perioperative complication and suggests a potential target for quality of care improvements.

Low-dose RATG with or without basiliximab in renal transplantation: a matched-cohort observational study

BACKGROUND/AIMS

In renal transplantation, peri-operative low-dose rabbit-antithymocyte-globulin (RATG) plus basiliximab induction prevented acute allograft rejection more effectively than post-operative RATG plus basiliximab induction. We investigated the specific antirejection contribution of basiliximab in this context.

METHODS

This single-center, observational, matched-cohort study evaluated allograft rejections (primary outcome), steroid exposure and side effects, GFR (iohexol plasma clearance) and treatment costs in 16 deceased-donor renal transplant recipients induced with RATG (0.5 mg/kg/day) and 32 age-, gender- and treatment-matched reference-patients given RATG plus basiliximab (20 mg on days 0 and 4).

RESULTS

Induction was well tolerated. At 18 months, 8 patients (50%) vs. 3 reference-patients (9.4%) rejected the graft [HR (95% CI): 6.53 (1.73-24.70), p = 0.006]. Difference was significant (p < 0.01) even after adjusting for recipient/donor age and gender, cold ischemia time and HLA mismatches. There were 1 antibody-mediated rejection and 2 moderate cellular rejections in patients vs. none in reference-patients (p = 0.032). The median (interquartile range) prednisone cumulative dose was remarkably higher in patients than reference-patients [4.78 (1.12-6.10) vs. 0.19 (0.18-3.81) grams, p = 0.002]. Three patients vs. 24 reference-patients were off-steroid at study end (p < 0.001). Three patients vs. no reference-patient developed new-onset diabetes (p = 0.003). Both inductions similarly depleted B-cells. Outcomes of AZA- vs. MMF-treated participants were similar. GFR was similar in all groups. Compared to MMF, AZA therapy saved ≈ EUR 2,500/year and by month 14.3 post-transplant compensated basiliximab costs.

CONCLUSION

In renal transplantation, basiliximab plus peri-operative low-dose RATG more efficiently prevented allograft rejection than RATG monotherapy, and minimized steroid exposure and toxicity. AZA- vs MMF-based maintenance immunosuppression largely compensated the extra costs of basiliximab.

Variation in biliary complication rates following liver transplantation: implications for cost and outcome

Although biliary complications (BCs) have a significant impact on the outcome of liver transplantation (LT), variation in BC rates among transplant centers has not been previously analyzed. BC rate, LT outcome and spending were assessed using linked Scientific Registry of Transplant Recipients and Medicare claims (n = 16,286 LTs). Transplant centers were assigned to BC quartiles based upon risk-adjusted observed to expected (O:E) ratio of BC separately for donation after brain death (DBD) and donation after cardiac death (DCD) donors. The median incidence of BC was 300% greater in the highest versus lowest DBD quartiles (19.0% vs. 5.9%) and varied 250% between DCD quartiles (20.3%-8.4%). Donor and recipient characteristics suggest that high BC centers actually used lower donor risk index organs, fewer split livers and fewer imports (p < 0.001 for all). Transplant at a center in the highest O:E quartile was associated with increased posttransplant mortality (adjusted hazard ratio [aHR] 2.53, p = 0.007) in DCD transplant and increased graft loss (aHR 1.21, p = 0.02) in DBD transplant. Medicare spending was $22,895 (p < 0.0001) higher at centers in highest versus lowest BC quartile. In summary, BC rates vary widely among transplant centers and higher rates are a marker for an increased risk of death, graft failure and health-care spending.

The efficacy and cost-effectiveness of valacyclovir in cytomegalovirus prevention in solid organ transplantation

Prevention of cytomegalovirus infection using antiviral prophylaxis or the pre-emptive therapy approach is an integral part of management of patients after solid organ transplantation. Regarding renal transplantation, valacyclovir is currently the only antiviral agent recommended for prophylaxis as an alternative to valganciclovir. This review article discusses studies documenting the efficacy and safety of valacyclovir prophylaxis as well as those comparing valacyclovir with other prophylactic regimens or with pre-emptive therapy. Also addressed are the economic aspects supporting the cost-effectiveness of valacyclovir prophylaxis and demonstrating lower costs compared with other cytomegalovirus preventive strategies.

Early clinical complications after ABO-incompatible live-donor kidney transplantation: a national study of Medicare-insured recipients

BACKGROUND

Descriptions of the sequelae of ABO-incompatible (ABOi) kidney transplantation are limited to single-center reports, which may lack power to detect important effects.

METHODS

We examined U.S. Renal Data System registry data to study associations of ABOi live-donor kidney transplantation with clinical complications in a national cohort. Among 14,041 Medicare-insured transplants in 2000 to 2007, 119 non-donor-A2 ABOi transplants were identified. A2-incompatible (n=35) transplants were categorized separately. Infection and hemorrhage events were identified by diagnosis codes on billing claims. Associations of ABO incompatibility with complications were assessed by multivariate Cox regression.

RESULTS

Recipients of ABOi transplants experienced significantly (P<0.05) higher incidence of wound infections (12.7% vs. 7.3%), pneumonia (7.6% vs. 3.8%), and urinary tract infections (UTIs) or pyelonephritis (24.5% vs. 15.3%) in the first 90 days compared with ABO-compatible recipients. In adjusted models, ABO incompatibility was associated with twice the risk of pneumonia (adjusted hazard ratio [aHR], 2.22; 95% confidence interval [CI], 1.14-4.33) and 56% higher risk of UTIs or pyelonephritis (aHR, 1.56; 95% CI, 1.05-2.30) in the first 90 posttransplantation days, and 3.5 times the relative risk of wound infections in days 91 to 365 (aHR, 3.55; 95% CI, 1.92-6.57). ABOi recipients, 19% of whom underwent pre- or peritransplant splenectomy, experienced twice the adjusted risk of early hemorrhage (aHR, 1.96; 95% CI, 1.19-3.24). A2-incompatible transplantation was associated only with early risk of UTIs or pyelonephritis.

CONCLUSION

ABOi transplantation offers patients with potential live donors an additional transplant option but with higher risks of infectious and hemorrhagic complications. Awareness of these complications may help improve protocols for the management of ABOi transplantation.

Long-term belatacept exposure maintains efficacy and safety at 5 years: results from the long-term extension of the BENEFIT study

The Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial randomized patients receiving a living or standard criteria deceased donor kidney transplant to a more (MI) or less intensive (LI) regimen of belatacept or cyclosporine A (CsA). The 5-year results of the long-term extension (LTE) cohort are reported. A total of 456 (68.5% of intent-to-treat) patients entered the LTE at 36 months; 406 patients (89%) completed 60 months. Between Months 36 and 60, death occurred in 2%, 1% and 5% of belatacept MI, belatacept LI and CsA patients, respectively; graft loss occurred in 0% belatacept and 2% of CsA patients. Acute rejection between Months 36 and 60 was rare: zero belatacept MI, one belatacept LI and one CsA. Rates for infections and malignancies for Months 36-60 were generally similar across belatacept groups and CsA, respectively: fungal infections (14%, 15%, 12%), viral infections (21%, 18%, 16%) and malignancies (6%, 6%, 9%). No new posttransplant lymphoproliferative disorder cases occurred after 36 months. Mean calculated GFR (MDRD, mL/min/1.73 m(2) ) at Month 60 was 74 for belatacept MI, 76 for belatacept LI and 53 for CsA. These results show that the renal function benefit and safety profile observed in belatacept-treated patients in the early posttransplant period was sustained through 5 years.

Long-term exposure to belatacept in recipients of extended criteria donor kidneys

Patients in the BENEFIT-EXT study received extended criteria donor kidneys and a more intensive (MI) or less intensive (LI) belatacept immunosuppression regimen, or cyclosporine A (CsA). Patients who remained on assigned therapy through year 3 were eligible to enter a long-term extension (LTE) study. Three hundred four patients entered the LTE (n = 104 MI; n = 113 LI; n = 87 CsA), and 260 continued treatment through year 5 (n = 91 MI; n = 100 LI; n = 69 CsA). Twenty patients died during the LTE (n = 5 MI; n = 9 LI; n = 6 CsA), and eight experienced graft loss (n = 2 MI; n = 1 LI; n = 5 CsA). Three patients experienced an acute rejection episode (n = 2 MI; n = 1 LI). The incidence rate of serious adverse events, viral infections and fungal infections was similar across groups during the LTE. There were four cases of posttransplant lymphoproliferative disorder (PTLD) from the beginning of the LTE to year 5 (n = 3 LI; n = 1 CsA); two of three PTLD cases in the LI group were in patients who were seronegative for Epstein-Barr virus (EBV(-)) at transplantation. Mean ± SD calculated GFR at year 5 was 55.9 ± 17.5 (MI), 59.0 ± 29.1 (LI) and 44.6 ± 16.4 (CsA) mL/min/1.73 m(2) . Continued treatment with belatacept was associated with a consistent safety profile and sustained improvement in renal function versus CsA over time.

Clinical correlates, outcomes and healthcare costs associated with early mechanical ventilation after kidney transplantation

BACKGROUND

Information is lacking on the frequency, clinical implications, and costs of respiratory failure requiring mechanical ventilation after kidney transplantation.

METHODS

U.S. Renal Data System records for Medicare-insured kidney transplant recipients (1995 to 2007; n = 88,392) were examined to identify post-transplantation mechanical ventilation from billing claims within 30 days after transplantation.

RESULTS

Post-transplantation mechanical ventilation was required among 2.1% of the cohort. Independent correlates of early mechanical ventilation included recipient age, low body mass index, coronary artery disease, and cerebrovascular disease. Post-transplantation mechanical ventilation was twice as likely with delayed graft function (adjusted odds ratio, 2.13; P < .001) and 35% lower among recipients of living versus deceased donor allografts. Patients needing early mechanical ventilation experienced 5-fold higher 1-year mortality, as well as significantly higher Medicare costs during the transplant hospitalization and first post-transplantation year.

CONCLUSIONS

Recognition of patients at risk for post-transplantation respiratory failure may help direct protocols for reducing the incidence and consequences of this complication.