Giselle Guerra

Effect of Kidney Transplantation on Outcomes among Patients with Hepatitis C

The long-term outcome of kidney transplantation in patients infected with hepatitis C virus (HCV) and end stage renal disease (ESRD) is not well described. We retrospectively identified 230 HCV-infected patients using enzyme immunoassay and nucleic acid testing obtained during the transplant evaluation. Of 207 patients who had a liver biopsy before transplant, 44 underwent 51 follow-up liver biopsies at approximately 5-year intervals either while on the waitlist for a kidney or after kidney transplantation. Advanced fibrosis was present in 10% of patients biopsied, identifying a population that may warrant consideration for combined liver-kidney transplantation. Kidney transplantation does not seem to accelerate liver injury; 77% of kidney recipients who underwent follow-up biopsies showed stable or improved liver histology. There was a higher risk for death during the first 6 months after transplant, but undergoing transplantation conferred a long-term survival advantage over remaining on the waitlist, which was evident by 6 months after transplant (HR, 0.32; 95% CI, 0.17 to 0.62). Furthermore, the risk for death resulting from infection was significantly higher during the first 6 months after transplant (HR, 26.6; 95% CI, 5.01 to 141.3), whereas there was an early (≤6 months) and sustained decrease in the risk for cardiovascular death (HR, 0.20; 95% CI, 0.08 to 0.47). In summary, these data suggest the importance of liver biopsy before transplant and show that kidney transplantation confers a long-term survival benefit among HCV-infected patients with ESRD compared with remaining on the waitlist. Nevertheless, the higher incidence of early infection-related deaths after transplant calls for further study to determine the optimal immunosuppressive protocol.

Disparities among Blacks, Hispanics, and Whites in time from starting dialysis to kidney transplant waitlisting.

Background Although a longer time on dialysis before kidney transplant waitlisting has been shown for Blacks versus non-Blacks, relatively few studies have compared this outcome between Hispanics and Whites. Methods A multivariable analysis of 1910 (684 Black, 452 Hispanic, and 774 White) consecutive patients waitlisted at our center for a primary kidney transplant between 2005 and mid-2010 was performed for time from starting dialysis to waitlisting (months), the percentage who were preemptively waitlisted (waitlisted before starting dialysis), and time from starting dialysis to waitlisting after excluding the preemptively waitlisted patients. Results The variables associated with significantly longer median times from starting dialysis to waitlisting and less preemptive waitlisting included Medicare insurance for patients ages <65 years (by far, the most significant variable in each analysis), Black race, higher percentage of households in the patient’s zip code living in poverty, being a non-U.S. citizen (for preemptive waitlisting), Medicaid insurance, waitlisted for kidney-alone (vs. kidney-pancreas) transplant, and higher body mass index (longer median times for the latter three variables). Although the effect of Black race was mostly explained by significant associations with lower socioeconomic status (Medicare insurance for patients ages <65 years and greater poverty in the patient’s zip code), an unexplained component still remained. The univariable differences showing poorer outcomes for Hispanics versus Whites were smaller and completely explained in multivariable analysis by significant associations with lower socioeconomic status and non-U.S. citizenship. Conclusion Black and Hispanic patients had significantly longer times from starting dialysis to waitlisting, in large part related to their lower socioeconomic status and less preemptive waitlisting. A greater focus on earlier nephrology care may help to erase much of these disparities.

Randomized Trial of Immunosuppressive Regimens in Renal Transplantation

The optimal long-term regimen for immunosuppression for kidney transplant recipients is unknown. We conducted a randomized trial involving 150 kidney transplant recipients to compare tacrolimus/sirolimus, tacrolimus/mycophenolate mofetil (MMF), and cyclosporine/sirolimus. All patients received daclizumab induction and maintenance corticosteroids. Median follow-up was 8 yr post-transplant. Acute rejection (AR) occurred significantly less often among those treated with tacrolimus/MMF (12%) than among those treated with tacrolimus/sirolimus (30%) or cyclosporine/sirolimus (28%). Mean estimated GFR was consistently higher in the tacrolimus/MMF arm, especially after controlling for donor age in a multivariable model during the first 36 mo (P ≤ 0.008). The rate of dying with a functioning graft was significantly higher among those treated with tacrolimus/sirolimus (26%) than among those treated with tacrolimus/MMF (12%) or cyclosporine/sirolimus (4%). We did not observe significant differences in actuarial graft survival at 8 yr post-transplant between the groups. Patient noncompliance seemed responsible for 45% (13/29) of observed graft failures, with 11 of these occurring after 36 mo. Significantly more viral infections, protocol violations, and need for antilipid therapy occurred among patients receiving sirolimus, but we did not observe differences between the groups with regard to infections requiring hospitalization or new-onset diabetes. Taken together, these results suggest that maintenance therapy with tacrolimus/MMF is more favorable than either tacrolimus/sirolimus or cyclosporine/sirolimus.

Graft failure due to noncompliance among 628 kidney transplant recipients with long-term follow-up: a single-center observational study.

Background In adult kidney transplantation, there is no clear consensus on the incidence of graft failure-due-to noncompliance (GFNC), with some reporting it as relatively uncommon and others as a major cause of late graft failure. We suspected that GFNC was a major cause of late graft loss at our center but did not know the extent of this problem. Methods In our prospectively followed cohort of 628 adult, primary kidney-alone transplant recipients with long-term follow-up, GFNC and other graft loss causes were determined from our ongoing clinical evaluations. Using competing risks methodology, we determined the overall percentage of patients developing GFNC and the significant prognostic factors for its hazard rate and cumulative incidence (via Cox regression). Results Cumulative incidence estimates (±standard error) of GFNC (n=29), GF-with-compliance (n=46), receiving a never-functioning graft (n=7), and death-with-a-functioning-graft (n=53) at 101 months after transplant (last-observed-graft loss) were as follows: 9.8%±2.4%, 10.9%±1.7%, 1.1%±0.4%, and 13.0%±1.9%, respectively. Only three patients experienced GFNC during the first 24 months; GFNC represented 48.1% (26/54) of death-censored GFs beyond 24 months. Two baseline variables were jointly associated with a significantly higher GFNC hazard and cumulative incidence: younger recipient age (P<0.000001 each) and non-white recipient (P=0.004 and P=0.02). Estimated percentages of ever developing GFNC were 28.4%±6.5% among 79 non-whites younger than 35 years versus 0.0% (0/144) among whites 50 years or older. Among 302 recipients younger than 50 years, 18.1%±4.1% developed GFNC, representing 67.6% (25/37) of its death-censored graft failures observed beyond 24 months after transplant. Conclusions GFNC is a major cause of late GF at our center, with younger and non-white recipients at a significantly greater GFNC risk. Interventional approaches to eliminate GFNC could dramatically improve long-term kidney graft survival.

Favorable outcomes with machine perfusion and longer pump times in kidney transplantation: a single-center, observational study.

Background. Hypothermic machine perfusion (MP) preservation is used for all deceased donor kidney transplants at our center. Kidneys are placed in cold storage at retrieval, then transferred to MP on arrival. Because a lack of consensus regarding optimal use of MP still exists, we evaluated the overall impact of using MP at our center and the prognostic value of MP (Pump) time. Methods. We retrospectively analyzed 339 adult, primary deceased donor kidney transplant recipients who were pooled across three prospective, randomized immunosuppression trials (since 2000) at our center. In addition to providing overall results for delayed graft function (DGF) (requirement for dialysis in the first week), slow graft function (SGF), first biopsy-proven acute rejection (BPAR), and graft failure, stepwise logistic and Cox regression analyses were used to determine the prognostic value of pump time, particularly after controlling for other significant prognosticators. Results. Mean cold storage and pump times were 6.6 and 26.7 hr, consistent across immunosuppression protocols. Overall DGF and SGF rates were 4.4% (15/339) and 12.1% (41/339). DGF was equally low for pump time less than 24 vs. more than or equal to 24 hr, 5.2% (6/116) vs. 4.0% (9/223) (P=0.63), with similar results after adjusting for known DGF predictors. A significantly lower first BPAR rate was observed for longer pump time (as a continuous variable) among more immunologically active recipients (those having more risk factors: DGF, age <50 yr, and non-white) (univariable P=0.005; multivariable P=0.009), with an estimated hazard ratio of 0.43 (P=0.006) favoring pump time more than or equal to 24 hr among those with more than or equal to two risk factors. Conclusions. In this single-center, observational study, MP with prolonged pump times was associated with low DGF/SGF and first BPAR rates, supporting continued use of MP.

Randomized trial of three induction antibodies in kidney transplantation: long-term results.

Background In searching for an optimal induction regimen, we conducted two separate randomized trials of 38 living donor and 90 deceased donor adult, primary kidney transplant recipients comparing antithymocyte globulin (Thymoglobulin) (group A, N=43) versus alemtuzumab (group B, N=43) versus daclizumab (group C, N=42), using exactly the same three treatment arms in each trial. Methods For the purpose of maximizing statistical power, results from the two randomized trials were combined. Groups A and C received standard maintenance dosing with tacrolimus (TAC), mycophenolate mofetil (MMF), and corticosteroids. Because of intense lymphodepletion expected with alemtuzumab use (and hoped-for achievement of a truer immunoregulatory state), group B received lower TAC and MMF dosing and corticosteroid avoidance. Long-term target TAC trough level and MMF dosing were 5 to 7 ng/mL and 1,000 mg b.i.d. in groups A and C; 4 to 6 ng/mL and 500 mg b.i.d. in group B. Results With median follow-up of 95 months, biopsy-proven cute rejection incidence was similar in the three groups (8/43, 14/43, and 12/42, P=0.34), but biopsy-proven chronic allograft injury incidence was significantly higher in group B (19/43) in comparison with groups A (9/43) and C (7/42) combined (P=0.0008). Mean calculated creatinine clearance was significantly lower in group B versus the average of groups A and C means throughout 60 months posttransplant (62.9±4.2 vs. 83.6±6.9 and 79.8±5.9 at 60 months, P=0.01), and death-censored graft failure was significantly higher in group B (13/43) versus groups A (5/43) and C (5/42) combined (P=0.009). Total infection and new-onset diabetes after transplant rates were not significantly different. Ad hoc analysis suggested that the inferior results in group B were specifically a result of reduced dosing and greater withholding of TAC and MMF occurring in that group. Conclusions Long-term results clearly indicate inferior clinical outcomes in group B.

Inhibitors of mTOR and risks of allograft failure and mortality in kidney transplantation

Data on long‐term outcomes of users of inhibitors of the mammalian target of rapamycin (mTORI) are lacking in kidney transplantation. In an analysis of 139 370 US kidney transplant recipients between 1999 through 2010, we compared clinical outcomes among users of mTORIs versus calcineurin inhibitors (CNI) in their primary immunosuppresive regimen. During the first 2 years posttransplantation, primary use of mTORIs without CNIs (N = 3237) was associated with greater risks of allograft failure and death compared with a CNI‐based regimen (N = 125 623); the hazard ratio (HR) of the composite outcome ranged from 3.67 (95% confidence interval [CI], 3.12–4.32) after discharge to 1.40 (95% CI 1.26–1.57) by year 2. During years 2–8, primary use of mTORIs without CNIs was independently associated with greater risks of death (HR 1.25; 95% CI, 1.11–1.41) and the composite (HR 1.17; 95%CI, 1.08–1.27) in fully adjusted analyses. The results were qualitatively unchanged in subgroups defined by medical history, immunological risk and clinical course during the index transplant hospitalization. In a propensity‐score matched cohort, use of mTORIs was associated with significantly worse outcomes during the first 2 years and greater risks of death (HR 1.21; 95% CI, 1.05–1.39) and the composite (HR 1.18; 95% CI, 1.08–1.30) in years 2–8. Compared with CNI‐based regimens, use of an mTORI‐based regimen for primary immunosuppression in kidney transplantation was associated with inferior recipient survival.

Transplantation of kidneys from hepatitis C-positive donors into hepatitis C virus-infected recipients followed by early initiation of direct acting antiviral therapy: A single-center retrospective study

The availability of direct acting antiviral agents (DAA) has transformed the treatment of hepatitis C virus (HCV) infection. The current study is a case series that reports the outcomes from a cohort of twenty‐five HCV‐infected ESRD patients who received a kidney from an anti‐HCV‐positive deceased organ donor followed by treatment with DAAs in the early post‐transplant period. Time to transplantation and the efficacy of DAA therapy as measured by sustained viral response at 12 weeks were assessed. The median waiting time from original date of activation on the United Network Organ Sharing (UNOS) waiting list until transplantation was 427 days; however, the median time from entering the patient into UNetsm for a HCV‐positive offer until transplantation was only 58 days. The 25 patients were started on antiviral treatment early post‐transplant (median 125 days) and 24 of 25 (96%) achieved a sustained virologic response at 12 weeks. Tacrolimus dose adjustments were required during antiviral treatment in 13 patients to maintain therapeutic levels. Accepting a kidney from an anti‐HCV‐positive deceased donor shortened the waiting time for HCV‐infected kidney transplant candidates. We recommend that kidneys from anti‐HCV‐positive donors should be considered for transplant into HCV‐infected recipients followed by early post‐transplant treatment with DAA agents.

Advantage of Rapamycin Over Mycophenolate Mofetil When Used With Tacrolimus for Simultaneous Pancreas Kidney Transplants: Randomized, Single‐Center Trial at 10 Years

Simultaneous pancreas kidney transplantation (SPKT) is the treatment of choice for patients with type 1 diabetes and end‐stage renal disease. Rapamycin and mycophenolate mofetil (MMF) have been used for maintenance immunosuppression with tacrolimus in SPKT; however, long‐term outcomes are lacking. From September 2000 through December 2009, 170 SPKT recipients were enrolled in a randomized, prospective trial receiving Rapamycin (n = 84) or MMF (n = 86). All patients received dual induction therapy with thymoglobulin and daclizumab, and low‐dose maintenance tacrolimus and corticosteroids. Compared to MMF, rates of freedom from first biopsy‐proven acute kidney or pancreas rejection were superior for Rapamycin at year 1 (kidney: 100% vs. 88%; P = 0.001; pancreas: 99% vs. 92%; P = 0.04) and at year 10 (kidney: 88% vs. 71%, P = 0.01; pancreas: 99% vs. 89%, P = 0.01). The higher rates of rejection were associated with withholding MMF (vs. Rapamycin, p = 0.009), generally for gastrointestinal or bone marrow toxicity. There was no significant difference in creatinine, proteinuria, c‐peptide, viral infections, lymphoproliferative disorders or posttransplant diabetes. HbA1C and lipid levels were normal in both groups, although higher in the Rapamycin arm. There were no significant differences in patient or allograft survival. In this 10‐year SPKT study, Rapamycin in combination with tacrolimus was better tolerated and more effective than MMF. Overall, the patient and allograft survival were equivalent.

Randomized trial of dual antibody induction therapy with steroid avoidance in renal transplantation.

Background. Given our previous experience using dual-induction therapy with antithymocyte globulin (ATG)/daclizumab (Dac) (each with fewer doses than if used alone), we chose to compare two distinct dual-induction strategies. Methods. Single-center, open-label randomized trial of 200 primary kidney transplant recipients was performed: (group I, n=100) ATG/Dac (3 ATG, 2 Dac doses) versus (group II, n=100) ATG/alemtuzumab (1 dose each), with maintenance consisting of reduced tacrolimus dosing (rTd), enteric-coated mycophenolate sodium (EC-MPS), and early corticosteroid withdrawal. One half of standard EC-MPS dosing was targeted in group II to avoid severe leukopenia previously seen with alemtuzumab. The goal in both arms was to achieve rapid and effective lymphocyte depletion while simultaneously allowing reduced maintenance immunosuppression. Primary endpoint was the incidence of biopsy-proven acute rejection (BPAR). Results. With median follow-up of 38 months, there were no differences in BPAR rates: 14 of 100 vs. 13 of 100 (including borderline) and 10 of 100 vs. 9 of 100 (excluding borderline) in groups I and II, respectively (nonsignificant). Actuarial patient/graft survival at 48 months was 96%/91% in group I vs. 92%/83% in group II (N.S.). Mean estimated glomerular filtration rate (±standard error) at 36 months was 72.1±3.3 vs. 67.5±3.3 in groups I and II (N.S.). Greater incidence of leukopenia occurred in group II at month 1 only (P=0.002). Percentages having EC-MPS withheld/discontinued due to leukopenia, gastrointestinal symptoms, and infection were 12 of 100, 7 of 100, and 0 of 100 in group I vs. 19 of 100, 0 of 100, and 2 of 100 in group II, respectively (P=0.01). Rates of new onset diabetes mellitus after transplantation and infections were equally low in both groups (no lymphoproliferative disorders were observed). Conclusions. These two distinct dual-induction therapies with rTd, EC-MPS, and planned early corticosteroid withdrawal resulted in favorable rates of BPAR and all secondary outcomes.