Characterizing the landscape and impact of infections following kidney transplantation.

Infections remain a major threat to successful kidney transplantation (KT). To characterize the landscape and impact of post-KT infections in the modern era, we used United States Renal Data System (USRDS) data linked to the Scientific Registry of Transplant Recipients (SRTR) to study 141 661 Medicare-primary kidney transplant recipients from January 1, 1999 to December 31, 2014. Infection diagnoses were ascertained by International Classification of Diseases, Ninth Revision (ICD-9) codes. The cumulative incidence of a post-KT infection was 36.9% at 3 months, 53.7% at 1 year, and 78.0% at 5 years. The most common infections were urinary tract infection (UTI; 46.8%) and pneumonia (28.2%). Five-year mortality for kidney transplant recipients who developed an infection was 24.9% vs 7.9% for those who did not, and 5-year death-censored graft failure (DCGF) was 20.6% vs 10.1% (P < .001). This translated to a 2.22-fold higher mortality risk (adjusted hazard ratio [aHR]: 2.15 2.222.29 , P < .001) and 1.92-fold higher DCGF risk (aHR: 1.84 1.911.98 , P < .001) for kidney transplant recipients who developed an infection, although the magnitude of this higher risk varied across infection types (for example, 3.11-fold higher mortality risk for sepsis vs 1.62-fold for a UTI). Post-KT infections are common and substantially impact mortality and DCGF, even in the modern era. Kidney transplant recipients at high risk for infections might benefit from enhanced surveillance or follow-up to mitigate these risks.

Center-level Variation in HLA-incompatible Living Donor Kidney Transplantation Outcomes.

BACKGROUND: Desensitization protocols for HLA-incompatible living donor kidney transplantation (ILDKT) vary across centers. The impact of these, as well as other practice variations, on ILDKT outcomes remains unknown. METHODS: We sought to quantify center-level variation in mortality and graft loss following ILDKT using a 25-center cohort of 1358 ILDKT recipients with linkage to Scientific Registry of Transplant Recipients for accurate outcome ascertainment. We used multilevel Cox regression with shared frailty to determine the variation in post-ILDKT outcomes attributable to between-center differences and to identify any center-level characteristics associated with improved post-ILDKT outcomes. RESULTS: After adjusting for patient-level characteristics, only 6 centers (24%) had lower mortality and 1 (4%) had higher mortality than average. Similarly, only 5 centers (20%) had higher graft loss and 2 had lower graft loss than average. Only 4.7% of the differences in mortality (P < 0.01) and 4.4% of the differences in graft loss (P < 0.01) were attributable to between-center variation. These translated to a median hazard ratio of 1.36 for mortality and 1.34 of graft loss for similar candidates at different centers. Post-ILDKT outcomes were not associated with the following center-level characteristics: ILDKT volume and transplanting a higher proportion of highly sensitized, prior transplant, preemptive, or minority candidates. CONCLUSIONS: Unlike most aspects of transplantation in which center-level variation and volume impact outcomes, we did not find substantial evidence for this in ILDKT. Our findings support the continued practice of ILDKT across these diverse centers.

Posttransplant Outcomes for cPRA-100% Recipients Under the New Kidney Allocation System.

BACKGROUND: There is concern in the transplant community that outcomes for the most highly sensitized recipients might be poor under Kidney Allocation System (KAS) high prioritization. METHODS: To study this, we compared posttransplant outcomes of 525 pre-KAS (December 4, 2009, to December 3, 2014) calculated panel-reactive antibodies (cPRA)-100% recipients to 3026 post-KAS (December 4, 2014, to December 3, 2017) cPRA-100% recipients using SRTR data. We compared mortality and death-censored graft survival using Cox regression, acute rejection, and delayed graft function (DGF) using logistic regression, and length of stay (LOS) using negative binomial regression. RESULTS: Compared with pre-KAS recipients, post-KAS recipients were allocated kidneys with lower Kidney Donor Profile Index (median 30% versus 35%, P < 0.001) but longer cold ischemic time (CIT) (median 21.0 h versus 18.6 h, P < 0.001). Compared with pre-KAS cPRA-100% recipients, those post-KAS had higher 3-year patient survival (93.6% versus 91.4%, P = 0.04) and 3-year death-censored graft survival (93.7% versus 90.6%, P = 0.005). The incidence of DGF (29.3% versus 29.2%, P = 0.9), acute rejection (11.2% versus 11.7%, P = 0.8), and median LOS (5 d versus 5d, P = 0.2) were similar between pre-KAS and post-KAS recipients. After accounting for secular trends and adjusting for recipient characteristics, post-KAS recipients had no difference in mortality (adjusted hazard ratio [aHR]: 0.861.623.06, P = 0.1), death-censored graft failure (aHR: 0.521.001.91, P > 0.9), DGF (adjusted odds ratio [aOR]: 0.580.861.27, P = 0.4), acute rejection (aOR: 0.610.941.43, P = 0.8), and LOS (adjusted LOS ratio: 0.981.161.36, P = 0.08). CONCLUSIONS: We did not find any statistically significant worsening of outcomes for cPRA-100% recipients under KAS, although longer-term monitoring of posttransplant mortality is warranted.

Pediatric deceased donor kidney transplant outcomes under the Kidney Allocation System.

The Kidney Allocation System (KAS) has resulted in fewer pediatric kidneys being allocated to pediatric deceased donor kidney transplant (pDDKT) recipients. This had prompted concerns that post-pDDKT outcomes may worsen. To study this, we used SRTR data to compare the outcomes of 953 pre-KAS pDDKT (age <18 years) recipients (December 4, 2012-December 3, 2014) with the outcomes of 934 post-KAS pDDKT recipients (December 4, 2014-December 3, 2016). We analyzed mortality and graft loss by using Cox regression, delayed graft function (DGF) by using logistic regression, and length of stay (LOS) by using negative binomial regression. Post-KAS recipients had longer pretransplant dialysis times (median 1.26 vs 1.07 years, P = .02) and were more often cPRA 100% (2.0% vs 0.1%, P = .001). Post-KAS recipients had less graft loss than pre-KAS recipients (hazard ratio [HR]: 0.35 0.540.83 , P = .005) but no statistically significant differences in mortality (HR: 0.29 0.721.83 , P = .5), DGF (odds ratio: 0.93 1.321.93 , P = .2), and LOS (LOS ratio: 0.96 1.061.19 , P = .4). After adjusting for donor-recipient characteristics, there were no statistically significant post-KAS differences in mortality (adjusted HR: 0.37 1.042.92 , P = .9), DGF (adjusted odds ratio: 0.94 1.412.13 , P = .1), or LOS (adjusted LOS ratio: 0.93 1.041.16 , P = .5). However, post-KAS pDDKT recipients still had less graft loss (adjusted HR: 0.38 0.590.91 , P = .02). KAS has had a mixed effect on short-term posttransplant outcomes for pDDKT recipients, although our results are limited by only 2 years of posttransplant follow-up.

Temporal Changes in the Impact of HLA Mismatching Among Pediatric Kidney Transplant Recipients.

BACKGROUND: Allocation for pediatric deceased-donor kidney transplantation (pDDKT) in the United States now de-emphasizes HLA matching to improve equality in access to transplantation, but other national systems still consider HLA matching due to concerns about graft survival. We hypothesized that the impact of HLA mismatching has decreased over time due to advances including improved immunosuppression. METHODS: Using Scientific Registry of Transplant Recipient data, we analyzed whether the association between the number of HLA mismatches and outcomes of first-time pDDKTs changed between 2 eras: 1995 to 2004 (N = 2854) and 2005 to 2014 (N = 4643). RESULTS: Between eras, the median number of mismatches increased from 4 to 5 (P < 0.001). Overall graft failure risk was higher among HLA-mismatched versus HLA-matched transplants (adjusted hazard ratio 1.211.431.69 for 3-6 versus 0-2 mismatches; P < 0.001), and this association was similar pre-2005 and post-2005 (Pinteraction = 0.5). Median panel-reactive antibody change at relisting increased from 79 to 85 (P = 0.01), but the association between number of HLA mismatches and panel-reactive antibody change was similar between eras (Pinteraction = 0.6). CONCLUSIONS: Our finding that increased HLA mismatching continues to impact graft survival, with 43% higher risk of graft failure, highlights the tradeoff between transplant access equity and outcomes and calls into question the deemphasis on HLA matching in pDDKT allocation in the United States.

Significantly Lower Rates of Kidney Transplantation among Candidates Listed with the Veterans Administration: A National and Local Comparison.

BACKGROUND: The process for evaluating kidney transplant candidates and applicable centers is distinct for patients with Veterans Administration (VA) coverage. We compared transplant rates between candidates on the kidney waiting list with VA coverage and those with other primary insurance. METHODS: Using the Scientific Registry of Transplant Recipients database, we obtained data for all adult patients in the United States listed for a primary solitary kidney transplant between January 2004 and August 2016. Of 302,457 patients analyzed, 3663 had VA primary insurance coverage. RESULTS: VA patients had a much greater median distance to their transplant center than those with other insurance had (282 versus 22 miles). In an adjusted Cox model, compared with private pay and Medicare patients, VA patients had a hazard ratio (95% confidence interval) for time to transplant of 0.72 (0.68 to 0.76) and 0.85 (0.81 to 0.90), respectively, and lower rates for living and deceased donor transplants. In a model comparing VA transplant rates with rates from four local non-VA competing centers in the same donor service areas, lower transplant rates for VA patients than for privately insured patients persisted (hazard ratio, 0.72; 95% confidence interval, 0.65 to 0.79) despite similar adjusted mortality rates. Transplant rates for VA patients were similar to those of Medicare patients locally, although Medicare patients were more likely to die or be delisted after waitlist placement. CONCLUSIONS: After successful listing, VA kidney transplant candidates appear to have persistent barriers to transplant. Further contemporary analyses are needed to account for variables that contribute to such differential transplant rates.

A Dynamic Clamp on Every Rig.

The dynamic clamp should be a standard part of every cellular electrophysiologist's toolbox. That it is not, even 25 years after its introduction, comes down to three issues: money, the disruption that adding dynamic clamp to an existing electrophysiology rig entails, and the technical prowess required of experimenters. These have been valid and limiting issues in the past, but no longer. Technological advances associated with the so-called maker movement render them moot. We demonstrate this by implementing a fast (∼100 kHz) dynamic clamp system using an inexpensive microcontroller (Teensy 3.6). The overall cost of the system is less than USD$100, and assembling it requires no prior electronics experience. Modifying it-for example, to add Hodgkin-Huxley-style conductances-requires no prior programming experience. The system works together with existing electrophysiology data acquisition systems (for Macintosh, Windows, and Linux); it does not attempt to supplant them. Moreover, the process of assembling, modifying, and using the system constitutes a useful pedagogical exercise for students and researchers with no background but an interest in electronics and programming. We demonstrate the system's utility by implementing conductances as fast as a transient sodium conductance and as complex as the Ornstein-Uhlenbeck conductances of the "point conductance" model of synaptic background activity.

Sevelamer Carbonate and Lanthanum Usage Evaluation and Cost Considerations at a Veteran's Affairs Medical Center.

BACKGROUND: Hyperphosphatemia is a common problem in patients with chronic kidney disease (CKD). Calcium-containing phosphate binders are typically used as first-line therapy, primarily due to cost considerations. Non-calcium phosphate binders such as sevelamer and lanthanum may be considered in the appropriate setting. It is hypothesized that lanthanum is less costly and has a lower pill burden compared to sevelamer carbonate. OBJECTIVE: Determine the difference in cost (outcome 1) and tablet burden (outcome 2) between sevelamer carbonate and lanthanum within the Veteran population. METHODS: Patients with an active prescription for lanthanum or sevelamer carbonate on October 22, 2014 were evaluated. Chi-square analysis was used to analyze categorical data, and 2-sided t test was used for continuous data. An α of 0.05 determined significance. RESULTS: One hundred fifty patients were included in the evaluation. Patients were predominately male (96%) and had a diagnosis of end stage renal disease (ESRD; 78%). The combined rate of non-dialysis CKD (ND-CKD) stage 5 and ESRD was similar between lanthanum and sevelamer carbonate groups. Both groups achieved similar phosphorus control (56% vs 65%, with phosphorus level less than or equal to 5.5 mg/dL, respectively; P = .23). Lanthanum prescriptions required significantly fewer tablets per day (4 lanthanum tablets daily vs 7 sevelamer carbonate tablets daily; P < .001). A potential prescription cost savings of approximately $4,500 monthly or $54,000 annually was seen when considering conversion of patients in this study population from sevelamer carbonate to lanthanum therapy, with appreciable savings beginning at sevelamer daily doses of at least 4,800 mg. CONCLUSIONS: Compared to sevelamer carbonate, lanthanum use was associated with reduced pill burden and lower absolute drug cost while maintaining similar phosphorus control.

Cyclosporine minimization and cost reduction in renal transplant recipients receiving a C2-monitored, cyclosporine-based quadruple immunosuppressive regimen.

BACKGROUND: Targeting 2-hr postdose cyclosporine (C2) levels to 1,000 to 1,700 mg/dL during the first 6 months after renal transplantation is recommended for triple immunosuppressive regimens. This trial determines whether lower C2 levels could be targeted safely in de novo kidney transplant recipients under a quadruple regimen compared with a similar cohort monitored with trough (C0) levels. METHODS: This single-center, sequential, cohort-designed trial included patients who received Thymoglobulin, corticosteroids, an antimetabolite, and cyclosporine monitored by C2 (n=50) or C0 (n=50). Cyclosporine was tapered to maintain the C2 between 1,000 and 1,200 ng/mL months 0 to 3 and between 600 and 1,000 ng/mL thereafter and C0 between 250 and 350 ng/mL months 0 to 3 and between 100 and 250 ng/mL thereafter. RESULTS: Baseline patient and donor characteristics were similar. There were no differences in graft survival (100% C2 vs. 100% C0), acute rejection (4% C2 vs. 6% C0), allograft function, or adverse events at 6 months. C2 levels were lower than the suggested guidelines throughout the study (33% lower at 1 month and 48% lower at 6 months). Lower cyclosporine doses were achieved in the C2 arm compared with the C0 arm by 1 month and were sustained throughout the trial, which translated into an average cyclosporine cost savings of USD $773 in the C2 arm during the 6-month period (P<0.001). CONCLUSION: With a quadruple immunosuppressive regimen and lower C2 targets than recommended for triple therapy, safe and effective cyclosporine minimization was achieved. Lower cyclosporine doses were achieved in C2-monitored patients compared with C0-monitored patients, translating into lower immunosuppressive costs.

Cost-effectiveness of extending Medicare coverage of immunosuppressive medications to the life of a kidney transplant.

Unless they maintain Medicare status through disability or age, kidney transplant recipients lose their Medicare coverage of immunosuppression 3 years after transplantation. A significant transplant survival advantage has previously been demonstrated by the extension of Medicare immunosuppressive medication coverage from 1 year to 3 years, which occurred between 1993 and 1995. The United States Renal Data System (USRDS) was analyzed for recipients of kidney transplants from 1995 to 1999. Using a Markov model, we estimated survival and costs of the current system of 3-year coverage compared with lifetime immunosuppression coverage. Results were calculated from the perspectives of society and Medicare. Extension of immunosuppression coverage produced an expected improvement from 38.6% to 47.6% in graft survival and from 55.4% to 61.8% in patient survival. The annualized expected savings to society from lifetime coverage was $136 million assuming current rates of transplantation. Medicare would break-even compared with current coverage if the fraction of patients using extended coverage was <32%. The extension would be cost-effective to Medicare if this fraction was <91%. Extended Medicare immunosuppression coverage to the life of a kidney transplant should result in better transplant and economic outcomes, and should be considered by policy makers.

Survival following liver transplantation from non-heart-beating donors.

OBJECTIVE: To determine whether patient and graft survival following transplantation with non-heart-beating donor (NHBD) hepatic allografts is equivalent to heart-beating-donor (HBD) allografts. SUMMARY BACKGROUND DATA: With the growing disparity between the number of patients awaiting liver transplantation and a limited supply of cadaveric organs, there is renewed interest in the use of hepatic allografts from NHBDs. Limited outcome data addressing this issue exist. METHODS: Retrospective evaluation of graft and patient survival among adult recipients of NHBD hepatic allografts compared with recipients of HBD livers between 1993 and 2001 using the United Network of Organ Sharing database. RESULTS: NHBD (N = 144) graft survival was significantly shorter than HBD grafts (N = 26856). One- and 3-year graft survival was 70.2% and 63.3% for NHBD recipients versus 80.4% and 72.1% (P = 0.003 and P = 0.012) for HBD recipients. Recipients of an NHBD graft had a greater incidence of primary nonfunction (11.8 vs. 6.4%, P = 0.008) and retransplantation (13.9% vs. 8.3%, P = 0.04) compared with HBD recipients. Prolonged cold ischemic time and recipient life support were predictors of early graft failure among recipients of NHBD livers. Although differences in patient survival following NHBD versus HBD transplant did not meet statistical significance, a strong trend was evident that likely has relevant clinical implications. CONCLUSIONS: Graft and patient survival is inferior among recipients of NHBD livers. NHBD donors remain an important source of hepatic grafts; however, judicious use is warranted, including minimization of cold ischemia and use in stable recipients.

Operative parameters that predict the outcomes of hepatic transplantation.

BACKGROUND: A growing discrepancy between the number of patients awaiting liver transplantation and the number of organs available mandates the use of even marginal organ donors in whom there is major risk of suboptimal graft function. A comprehensive analysis of operative parameters on the outcomes of liver transplantation has not been reported. STUDY DESIGN: We analyzed the impact of 24 operative variables on the survival of 942 consecutive primary liver allografts performed at a single center from June 1992 through December 1997. Univariate and Cox proportional hazards analysis was used to identify those variables with independent prognostic significance in graft survival. Resource utilization for variables with multivariate significance was also analyzed. RESULTS: Of 12 intraoperative variables found to have significance in univariate analysis, three were significant by Cox multivariate analysis: 1) lack of immediate bile production by the graft intraoperatively, 2) platelet transfusion > or = 20 U, and 3) recipient urine output < or =2.0 mL/kg/h intraoperatively. Each of the three variables was associated with marked increases in hospital and Intensive Care Unit length of stay and hospital charges accrued during the admission for transplantation. CONCLUSION: We identified three operative parameters that predict a poor outcome after liver transplantation. The presence of these indicators suggests that early retransplantation should be considered. Early identification of grafts likely to have poor function might also provide an opportunity for therapeutic intervention to salvage graft function.