Recent Trends in Kidney Transplant in the United States

The number of new wait list registrants has increased in the last decade but not to the same magnitude as the increase in the number of end stage renal disease patients in the United States. The number of wait list patients has increased at a much higher pace due to the lack of kidney supply. The overall number of kidney transplants only increased slightly. Paired exchange kidney transplant is a viable source of increasing the availability of kidney transplant and also offers access to transplant to patients with immunologic barriers to their intended donors. Paired donor exchange results in similar outcomes despite recipients' having a higher immunologic risk profile. The kidney allocation system (KAS) was recently implemented and so far has resulted in more access for patients with very high immunologic risk and allocation of lower kidney donor profile index organs to younger recipients. Longer follow up is needed to determine the net benefit of the KAS.

Impact of Diabetes Mellitus on Survival Outcome of Lung Transplant Recipients: An Analysis of OPTN/UNOS Data

BACKGROUND

There are limited data on the outcome of diabetic lung recipients, especially in those with new-onset diabetes after transplantation (NODAT).

METHODS

We studied prevalence of pre-transplant diabetes mellitus (PDM) and cumulative incidence of NODAT in lung recipients using the Organ Procurement and Transplantation Network /United Network for Organ Sharing database. Between 2004 and 2011, adult (≥18 years old) recipients transplanted with either first single- or double-lung were included. Those who lacked a diabetes record or received multi-organ transplants were excluded. Patient survival were studied in recipients who had functioning grafts for at least one year.

RESULTS

There were 10,226 recipients who had at least one diabetes record, the prevalence of PDM was 18.25% and the cumulative incidence of NODAT during the five years post-transplant was 39.43%. Of 9,117 recipients who had functioning grafts for at least one year, adjusted hazard ratios (HR) of PDM and NODAT, compared to the diabetes-free group, were 1.12 (p=0.048) and 1.12 (p=0.025), respectively. Independent risk factors for mortality included the presence of rejection in the one year, cytomegalovirus serology donor positive/recipient negative, and recipient age >60 years. Among recipients with cystic fibrosis, there was no statistical difference in mortality between diabetic recipients and the diabetes-free group. Compared to the diabetes-free group, the adjusted HRs for mortality of PDM and NODAT in recipients without cystic fibrosis were 1.15 (p=0.031) and 1.14 (p=0.011), respectively.

CONCLUSIONS

Diabetes was associated with mortality in lung transplant recipients overall and in lung recipients without cystic fibrosis. However, there was no association between diabetes and mortality in lung recipients with cystic fibrosis.

Novel once-daily extended-release tacrolimus (LCPT) versus twice-daily tacrolimus in de novo kidney transplants: one-year results of Phase III, double-blind, randomized trial

This Phase III randomized trial examined efficacy and safety of a novel once-daily extended-release tacrolimus formulation (LCP-Tacro [LCPT]) versus twice-daily tacrolimus in de novo kidney transplantation. Primary efficacy end point was proportion of patients with treatment failure (death, graft failure, biopsy-proven acute rejection or lost to follow-up) within 12 months. Starting doses were, LCPT: 0.17 mg/kg/day and tacrolimus twice-daily: 0.1 mg/kg/day; 543 patients were randomized, LCPT: n = 268; tacrolimus twice-daily: n = 275. At 12 months treatment failure was LCPT: 18.3% and tacrolimus twice-daily: 19.6%; the upper 95% CI of the treatment difference was +5.27%, below the predefined +10% noninferiority criteria. There were no significant differences in the incidence of individual efficacy events or adverse events. Target tacrolimus trough levels were more rapidly achieved in the LCPT group. Following initial dose, 36.6% of patients in the LCPT group had rapidly attained trough levels within 6-11 ng/mL versus 18.5% of tacrolimus twice-daily patients; majority of tacrolimus twice-daily patients (74.7%) had troughs <6 ng/mL compared with 33.5% in the LCPT group. Overall, cumulative study dose was 14% lower for LCPT. Results suggest that use of once-daily LCPT in de novo kidney transplantation is efficacious and safe. Lower LCPT dose reflects the improved absorption provided by the novel formulation.

Changes in the small bowel of symptomatic kidney transplant recipients converted from mycophenolate mofetil to enteric-coated mycophenolate sodium

BACKGROUND/AIMS

Gastrointestinal (GI) symptoms in renal transplant recipients may be caused due to mycophenolic acid (MPA) toxicity. Using small bowel capsule endoscopy (SBCE) we examined the impact of conversion from Mycophenolate Mofetil (MMF) to enteric-coated formulation of Mycophenolate Sodium (EC-MPS) given to treat GI mucosal lesions.

METHODS

Adult kidney-only recipients at least 30 days after transplant, presenting with GI symptoms while receiving MMF completed a Gastrointestinal Symptom Rating Scale (GSRS) questionnaire, underwent SBCE, and had MMF substituted by EC-MPS. After 30 days, GSRS and SBCE were repeated and findings were compared to baseline values. Patients who were still on EC-MPS 6-24 months post-conversion were contacted for completing a follow-up GSRS questionnaire and SBCE.

RESULTS

Eighteen out of 23 subjects completed the first part of the study. Subjects' median ages and post-transplant time were 47.5 years old and 4.5 months, respectively. Tacrolimus, MMF and prednisone was the main regimen (94%), with a median MMF dose of 750 mg BID. The average baseline GSRS was 2.99 ± 0.81; it significantly decreased to 2.19 ± 0.8 at 30 days post-conversion. At baseline, 50 had gastric and 89% had small bowel lesions. At 30 days, 29 and 62% of the SBCE were still showing gastric and small bowel lesions, respectively. Of 5 patients in the study extension, 4 had abnormal SBCE findings but have been reporting improvement in their symptoms.

CONCLUSION

Stomach and small bowel mucosal lesions are common in kidney recipients with GI symptoms when treated with MMF. Conversion to EC-MPS for 30 days significantly alleviated the GI symptoms; however, no evident correlation with SBCE findings was found.

Renal dysfunction in end-stage liver disease and post-liver transplant

Renal dysfunction is a frequent complication in patients with end-stage liver disease awaiting orthotopic liver transplantation and in the post-liver transplant period. Although the stereotypical form of renal dysfunction is the hepatorenal syndrome, other causes of acute kidney injury in this population include prerenal azotemia and acute tubular necrosis. Renal injury in a patient with cirrhosis is associated with a poor prognosis.

Renal Transplant Outcomes in Waitlist Candidates with a Previous Inactive Status Due to Being Temporarily Too Sick

BACKGROUND

In 2003, the United Network for Organ Sharing (UNOS) changed its policy to allow candidates with 'inactive' status to accrue time on the waitlist. In this study, we assessed the transplant outcomes among deceased donor kidney transplant (DDKT) recipients who were temporarily inactive specifically due to medical reason, i.e., being temporarily too sick (reason 7).

METHODS

Using the UNOS database, adult DDKT recipients were divided into two groups: those who had never been inactivated (active group) and those with a history of being inactive due to reason 7 (reason 7 group). Patient and graft survival, 3-year risk of death, and graft failure were examined and compared.

RESULTS

After 3 years of follow-up, patient survival in the reason 7 group was significantly lower than that of the active group (88.14% versus 91.93%, p < 0.01). The reason 7 group had a 20% increased risk of death (hazard ratio, HR 1.20, confidence interval, CI 1.04 - 1.38), a 16% increase in graft failure (HR 1.16, CI 1.06-1.28), and a 15% decrease in death-censored graft failure (HR 1.15, CI 1.01-1.31).

CONCLUSION

Recipients with a history of reason 7 have lower patient and graft survival when compared to the active group. Nonetheless, the margins of difference are minimal. Candidates with a history of reason 7 should not be discouraged from transplantation once they return to active status. Standardized criteria for placing candidates on inactive status should be developed to reduce disparities among transplant centers.

The UNOS Renal Transplant Registry: Review of the Last Decade

Kidney transplantation has become a preferred treatment for end-stage renal disease (ESRD) as transplant recipients enjoy freedom from dialysis and improvement in both quality and quantity of life. More patients are being placed on the transplant waiting list, although the waiting list patients still only represent a very small fraction of ESRD patients. The characteristics of both waitlisted and transplanted patients have changed considerably in the last decade, as the ESRD population has aged and waiting list times have increased. Over the last 10 years, we have witnessed an increasingly severe shortage of kidney donors. Even with increasing efforts of the transplant community to expand the donor pool by including larger numbers of high risk deceased donor transplants, the overall number of kidney transplants has remained relatively stable. Those who do receive transplants, however, benefit from excellent transplant outcomes. The use of paired exchange/chain transplant donors has increased the living donor pool significantly and with outstanding results. Belatacept, a costimulation blockage drug, represents a new class of transplant immunosuppression. It has been used sparingly in the first few years of its approval. Most kidney transplant patients are still maintained on immunosuppressive agents that were approved almost two decades ago. In the next decade, we will certainly continue to deal with an organ shortage as the number of eligible and waitlisted patients is likely to increase. Effective and efficient organ allocation policies will be increasingly necessary to address this scarcity. Optimizing the transplant candidate work-up, improving maintenance of waitlisted patients, and providing optimal post-transplant medical care will be vital to the continued success of kidney transplantation.

Can aminotransferase-to-platelet ratio index and other non-invasive markers effectively reduce liver biopsies for renal transplant evaluation of hepatitis C virus-positive patients?

BACKGROUND

Advanced fibrosis or cirrhosis is still regarded as a contraindication for kidney transplantation alone by most centers. The value of aminotransferase to platelet ratio index (APRI) and other non-invasive markers has been less studied in hepatitis C virus (HCV)-positive patients with concurrent end-stage renal disease to predict hepatic fibrosis. Can these be used to effectively decrease the number of biopsies done in these patients being evaluated for transplantation?

METHODS

Our study population included 255 patients with liver biopsy data. All patient information was collected and reviewed from medical records. The diagnostic accuracy of the predictive models was analyzed by calculating sensitivity, specificity, positive predictive value and negative predictive value.

RESULTS

The variables associated with F3-F4 were aspartate aminotransferase (P = 0.007), bilirubin (P ≤ 0.001), platelet count (P = 0.01) and APRI (P ≤ 0.001). The use of any one laboratory abnormality to predict liver biopsy scores did not show high positive predictive values (22.6-72.7%). Having abnormal liver findings or cirrhosis on imaging was associated with high specificities (92.0-97.8%) but low sensitivities (31.4-42.9%). Using APRI levels of ≥0.40 and ≤0.95 as an indication for liver biopsy, 50% of patients with F3-F4 would have correctly avoided having a biopsy. However, 33% of patients with F3-F4 would have been mislabeled and not be indicated for biopsy.

CONCLUSIONS

Our data suggest that there may not currently be a simple and sufficiently accurate non-invasive test to replace liver biopsy in renal transplant workup for HCV-positive patients. The risks outweigh the benefits when it comes to using non-invasive markers like the APRI.

Conversion from twice-daily tacrolimus capsules to once-daily extended-release tacrolimus (LCPT): a phase 2 trial of stable renal transplant recipients

BACKGROUND

LCP-Tacro is an extended-release formulation of tacrolimus designed for once-daily dosing. Phase 1 studies demonstrated greater bioavailability to twice-daily tacrolimus capsules and no new safety concerns.

METHODS

In this phase 2 study, adult stable kidney transplant patients on tacrolimus capsules (Prograf) twice-daily were converted to tacrolimus tablets (LCP-Tacro) once-daily; patients continued on LCP-Tacro once-daily for days 8 to 21; trough levels were to be maintained between 5 and 15 ng/mL; 24-hr pharmacokinetic assessments were done on days 7 (baseline pre-switch), 14, and 21.

RESULTS

Forty-seven patients completed LCP-Tacro dosing per protocol. The mean conversion ratio was 0.71. Pharmacokinetic data demonstrated consistent exposure (AUC) at the lower conversion dose. C(max) (P = 0.0001), C(max)/C(min) ratio (P < 0.001), percent fluctuation (P < 0.0001), and swing (P = 0.0004) were significantly lower and T(max) significantly (P < 0.001) longer for LCP-Tacro versus Prograf. AUC24 and C(min) correlation coefficients after 7 and 14 days of therapy were 0.86 or more, demonstrating a robust correlation between LCP-Tacro tacrolimus exposure and trough levels. There were three serious adverse events; none were related to study drug and all were resolved.

CONCLUSIONS

Stable kidney transplant patients can be safely converted from Prograf twice-daily to LCP-Tacro. The greater bioavailability of LCP-Tacro allows for once-daily dosing and similar (AUC) exposure at a dose approximately 30% less than the total daily dose of Prograf. LCP-Tacro displays flatter kinetics characterized by significantly lower peak-trough fluctuations.

Conversion from twice-daily tacrolimus to once-daily extended release tacrolimus (LCPT): the phase III randomized MELT trial

Phase III noninferiority trial examining efficacy and safety of converting stable renal transplant recipients from twice-daily tacrolimus to a novel extended-release once-daily tacrolimus formulation (LCPT) with a controlled agglomeration technology. Controls maintained tacrolimus twice daily. The primary efficacy endpoint was proportion of patients with efficacy failures (death, graft failure, locally read biopsy-proven acute rejection [BPAR], or loss to follow-up) within 12 months. Starting LCPT dose was 30% lower (15% for blacks) than preconversion tacrolimus dose; target trough levels were 4-15 ng/mL. A total of 326 patients were randomized; the mITT population (n = 162 each group) was similar demographically in the two groups. Mean daily dose of LCPT was significantly (p < 0.0001) lower than preconversion tacrolimus dose at each visit; mean trough levels between groups were similar. There were four efficacy failures in each group; safety outcomes were similar between groups. Frequency of premature study drug discontinuation was LCPT: 12% versus tacrolimus twice daily: 5% (p = 0.028). LCPT demonstrated noninferiority to tacrolimus twice daily in efficacy failure rates. LCPT may offer a safe and effective alternative for converting patients to a once-daily formulation. Compared to currently available tacrolimus formulation, LCPT requires lower doses to achieve target trough levels.

Improved survival among sickle cell kidney transplant recipients in the recent era

BACKGROUND

Studies from older cohorts of kidney recipients have observed that recipients with sickle cell disease (SCD) have lower patient survival compared with age- and race-matched controls. We examined whether survival has improved among SCD recipients in the current era.

METHODS

Using Organ Procurement and Transplantation Network/United Network for Organ Sharing data, all black/African-American kidney recipients were stratified according to transplant year into an early (1988-99) and recent era (2000-11). Patient and allograft survival among SCD recipients and those with other diagnoses were compared (early era: SCD n = 67, others n = 20 694; recent era: SCD n = 106, others n = 34 428). A secondary-matched cohort analysis compared patient and allograft survival between SCD recipients matched to recipients with other diagnoses based on recipient and donor age, gender and donor type (deceased versus living).

RESULTS

Patient survival at 6 years was lower among SCD recipients in the early era compared with other diagnoses (55.7 versus 78.0%; P < 0.001). Six-year patient survival among sickle cell recipients improved in the recent era (69.8%; P versus early era = 0.04), although still trended toward lower survival compared with other diagnoses (80.0%; P = 0.07). Multivariate Cox proportional hazard models revealed an increased mortality risk with SCD in both eras [early: hazard ratio (HR) = 3.12; 95% confidence interval (CI): 2.15-4.54; recent: HR: 2.03; 95% CI: 1.31-3.16]. Patient survival among matched SCD recipients in the recent era was comparable to diabetic recipients (SCD: 73.1%, diabetes: 74.1%; P = 0.44).

CONCLUSIONS

Patient survival has improved among contemporary sickle cell recipients compared with an earlier cohort and is comparable to a matched cohort of diabetic kidney recipients. Appropriately selected SCD patients may receive kidney transplants with reasonable survival outcome.

Kidney failure requiring kidney transplantation after pancreas transplant alone

Pancreas transplant alone (PTA) is usually performed in type 1 diabetic patients with preserved renal function to correct severe metabolic complications. One of the major concerns is renal failure after PTA. Here, we reported the cumulative incidence of kidney failure requiring kidney transplantation (KF/KT) among PTA recipients in the United States. Using the Organ Procurement Transplant Network/ United Network for Organ Sharing database, all primary adult PTA recipients with estimated baseline glomerular filtration rate (by the Modification of Diet in Renal Disease equation) >or=60 mL/min/1.73m2 were selected (n=1085). KF/ KT after PTA was defined as: wait-listing for or receiving a kidney alone (KA) or simultaneous pancreas kidney (SPK) transplant. The median follow-up time was 1185 days (25-75%: 524-2183). Ten years post PTA, 120 (11.1%) patients developed KF/KT; of those, 70 (6.5%) subsequently received a KA/SPK transplant (56 received KA and 14 received SPK) and 50 (4.6%) recipients were listed without receiving a transplant. The cumulative incidence of KF/KT after PTA at 1, 3, and 5 years after PTA was 0.3, 2.5, and 9.7%, respectively. In conclusion, KF/KT after PTA was not uncommon (9.7% at 5 years), and prospective PTA recipients should be aware of the risks of kidney failure after transplantation.

Donor race and outcomes in kidney transplant recipients

BACKGROUND

African Americans are at greater risk to reach end-stage renal disease and this risk may carry over in a kidney transplant recipient after kidney transplantation.

METHODS

Linking the five-yr patient data of a large dialysis organization to the Scientific Registry of Transplant Recipients, we identified 13 692 hemodialysis patients who underwent first kidney transplantation. Mortality or graft failure and delayed graft function risks were estimated by Cox's regression (hazard ratio [HR] and 95% confidence interval) and logistic regression, respectively.

RESULTS

Patients were 48 ± 14 yr old and included 39% women and 26% patients with diabetes. After adjusting for several relevant clinical and transplant-related variables, African American donor race was associated with higher all-cause mortality, with HR of 1.39 (1.09-1.78) for all-cause mortality, 1.80 (1.17-2.76) for cardiovascular mortality, 1.30 (1.03-1.64) for death-censored graft loss and 1.31 (1.10-1.57) for combined outcome over the six-yr observation period. In the non-African American recipient subcohort, but not in the African American recipient subcohort, African American donor race was associated with higher risk of death-censored graft loss (2.24 [1.44-3.49]) in our fully adjusted model.

CONCLUSIONS

African American donor race was associated with increased all-cause and cardiovascular mortality and graft loss.

Association of pre-transplant erythropoiesis-stimulating agent responsiveness with post-transplant outcomes

BACKGROUND

The role of pre-transplant erythropoiesis-stimulating agent (ESA) responsiveness in affecting post-transplant outcomes is not clear.

METHODS

Linking the 5-year patient data of a large dialysis organization to the 'Scientific Registry of Transplant Recipients', we identified 8795 hemodialyzed patients who underwent first kidney transplantation. Mortality or graft failure, delayed graft function (DGF) and acute rejection risks were estimated by Cox regression [hazard ratio (HR)] and logistic regression, respectively.

RESULTS

Patients were 48 ± 14 years old and included 38% women and 36% diabetics. Compared to renal allograft recipients who were in the first quartile of pre-transplant ESA responsiveness index (ERI), i.e. ESA dose divided by hemoglobin and weight, recipients in second, third and fourth quartiles had higher adjusted graft-censored death HR (and 95% confidence intervals) of 1.7 (1.0-2.7), 1.8 (1.1-2.9) and 2.3 (1.4-3.9) and higher death-censored graft failure HR of 1.6 (1.0-2.5), 2.0 (1.2-3.1) and 1.6 (0.9-2.6), respectively. No significant association between pre-transplant ERI and post-transplant DGF or acute rejection was detected.

CONCLUSIONS

Higher pre-transplant ERI during the hemodialysis treatment period was associated with worse post-transplant long-term outcomes including increased all-cause death and higher risk of graft failure.

Associations of pre-transplant anemia management with post-transplant delayed graft function in kidney transplant recipients

BACKGROUND

Delayed graft function (DGF) complicates kidney allograft outcomes in the immediate post-transplantation period. We hypothesized that in hemodialysis patients more severe anemia, iron deficiency, the requirement for higher doses of erythropoietin-stimulating agents (ESA), or blood transfusions prior to transplantation are associated with higher risk of DGF.

METHODS

Linking five-yr hemodialysis patient data of a large dialysis organization to the Scientific Registry of Transplant Recipients, we identified 11 836 hemodialysis patients. Using logistic regression analyses we examined the association between pre-transplant parameters and post-transplant DGF.

RESULTS

Patients were 49 ± 14 (mean ± SD) yr old and included 38% women, 27% blacks, and 26% diabetics. After adjusting for relevant covariates, pre-transplant blood transfusion was associated with 33% higher DGF risk (odds ratio [OR] = 1.33; 95% confidence interval [CI]: 1.19-1.48); and each 5000 U/wk increase of pre-transplant ESA dose with 5% higher DGF (OR = 1.05; 95% CI: 1.02-1.09). Compared to pre-transplant blood hemoglobin of 12-12.99 g/dL, there was 25% higher risk of DGF with blood hemoglobin 10-10.99 g/dL (OR = 1.25; 95% CI: 1.01-1.55), whereas blood hemoglobin ≥13 g/dL exhibited 15% higher risk of DGF (OR = 1.15; 95% CI: 0.98-1.34).

CONCLUSIONS

Pre-transplant blood transfusion, higher ESA dose, and either high or low blood hemoglobin but not iron markers are associated with higher risk of DGF.

Timing of dialysis initiation in transplant-naive and failed transplant patients

Over the past two decades, most guidelines have advocated early initiation of dialysis on the basis of studies showing improved survival in patients starting dialysis early. These recommendations led to an increase in the proportion of patients initiating dialysis with an estimated glomerular filtration rate (eGFR) >10 ml/min/1.73 m(2), from 20% in 1996 to 52% in 2008. During this period, the percentage of patients starting dialysis with an eGFR ≥15 ml/min/1.73 m(2) increased from 4% to 17%. However, recent studies have failed to substantiate a benefit of early dialysis initiation and some data have suggested worse outcomes for patients starting dialysis with a higher eGFR. Several reasons for this seemingly paradoxical observation have been suggested, including the fact that patients requiring early dialysis are likely to have more severe symptoms and comorbidities, leading to confounding by indication, as well as biological mechanisms that causally relate early dialysis therapy to adverse outcomes. Patients with a failing renal allograft who reinitiate dialysis encounter similar problems. However, unique factors associated with a failed allograft means that the optimal timing of dialysis initiation in failed transplant patients might differ from that in transplant-naive patients with chronic kidney disease. In this Review, we discuss studies of dialysis initiation and compare risks and benefits of early versus late initiation and reinitiation of dialysis therapy.

Age and the associations of living donor and expanded criteria donor kidneys with kidney transplant outcomes

BACKGROUND

Recent studies show a survival advantage with kidney transplant in elderly patients compared with those on dialysis therapy.

STUDY DESIGN

In our present study, we examined and compared the association of expanded criteria donor (ECD) kidney and living kidney donation with the outcome of kidney transplant across different ages, including elderly recipients.

SETTING & PARTICIPANTS

Using the Scientific Registry of Transplant Recipients, we identified 145,470 adult kidney transplant patients. Mortality and death-censored transplant failure risks were estimated by Cox proportional regression analyses during follow-up with a median of 3.9 years.

PREDICTORS

ECD kidney and living kidney donation and age compared with others.

OUTCOMES

Mortality and death-censored transplant failure risk.

RESULTS

Patients were aged 45 ± 16 years and included 40% women and 19% patients with diabetes. Compared with transplant recipients 55 to younger than 65 years, the fully adjusted death-censored transplant failure risk was higher in patients 75 years and older (HR, 1.30; 95% CI, 1.09-1.56), 35 to younger than 55 years (HR, 1.13; 95% CI, 1.08-1.17), and 18 to younger than 35 years (HR, 1.64; 95% CI, 1.57-1.71). Compared with non-ECD kidneys, ECD kidneys were significant predictors of mortality in nonelderly patients (18-<35 years: HR, 1.46 [95% CI, 1.19-1.77]; 35-<55 years: HR, 1.23 [95% CI, 1.14-1.32]; and 55-<65 years: HR, 1.26 [95% CI, 1.15-1.38]) and patients 65 to younger than 70 years (HR, 1.20; 95% CI, 1.05-1.36), but not in other groups of elderly patients (HRs of 1.12 [95% CI, 0.93-1.36] for 70-<75 years and 1.04 [95% CI, 0.74-1.47] for ≥75 years). Similar results were found for risk of transplant loss. Compared with deceased donor kidneys, a living donor kidney was associated with better survival in all age groups and lower transplant loss risk in patients younger than 70 years.

LIMITATIONS

Unmeasured confounders cannot be adjusted for.

CONCLUSIONS

For deceased donors, ECD kidneys are not associated with increased mortality or transplant failure in recipients older than 70 years. For all types of donors, the persistent association between living donor kidneys and lower all-cause mortality across all ages suggests that, if possible, elderly patients gain longevity from living donor kidney transplant.

Cardiorenal syndrome and vitamin D receptor activation in chronic kidney disease

Cardiorenal syndrome (CRS) refers to a constellation of conditions whereby heart and kidney diseases are pathophysiologically connected. For clinical purposes, it would be more appropriate to emphasize the pathophysiological pathways to classify CRS into: (1) hemodynamic, (2) atherosclerotic, (3) uremic, (4) neurohumoral, (5) anemic–hematologic, (6) inflammatory–oxidative, (7) vitamin D receptor (VDR) and/or FGF23-, and (8) multifactorial CRS. In recent years, there have been a preponderance data indicating that vitamin D and VDR play an important role in the combination of renal and cardiac diseases. This review focuses on some important findings about VDR activation and its role in CRS, which exists frequently in chronic kidney disease patients and is a main cause of morbidity and mortality. Pathophysiological pathways related to suboptimal or defective VDR activation may play a role in causing or aggravating CRS. VDR activation using newer agents including vitamin D mimetics (such as paricalcitol and maxacalcitol) are promising agents, which may be related to their selectivity in activating VDR by means of attracting different post-D-complex cofactors. Some, but not all, studies have confirmed the survival advantages of D-mimetics as compared to non-selective VDR activators. Higher doses of D-mimetic per unit of parathyroid hormone (paricalcitol to parathyroid hormone ratio) is associated with greater survival, and the survival advantages of African American dialysis patients could be explained by higher doses of paricalcitol (>10 μg/week). More studies are needed to verify these data and to explore additional avenues for CRS management via modulating VDR pathway.

Dialysis modality and outcomes in kidney transplant recipients

BACKGROUND AND OBJECTIVES

The influence of pretransplant dialysis modality on post-transplant outcomes is not clear. This study examined associations of pretransplant dialysis modality with post-transplant outcomes in a large national cohort of kidney transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Linking the 5-year patient data of a large dialysis organization to the Scientific Registry of Transplant Recipients, 12,416 hemodialysis and 2092 peritoneal dialysis patients who underwent first kidney transplantation were identified. Mortality or graft failure and delayed graft function risks were estimated by Cox regression (hazard ratio) and logistic regression (odds ratio), respectively.

RESULTS

Recipients treated with peritoneal dialysis pretransplantation had lower (21.9/1000 patient-years [95% confidence interval: 18.1-26.5]) crude all-cause mortality rate than those recipients treated with hemodialysis (32.8/1000 patient-years [30.8-35.0]). Pretransplant peritoneal dialysis use was associated with 43% lower adjusted all-cause and 66% lower cardiovascular death. Furthermore, pretransplant peritoneal dialysis use was associated with 17% and 36% lower unadjusted death-censored graft failure and delayed graft function risk, respectively. However, after additional adjustment for relevant covariates, pretransplant peritoneal dialysis modality was not a significant predictor of death-censored graft failure delayed graft function, respectively. Similar trends were noted on analyses using a propensity score matched cohort of 2092 pairs of patients.

CONCLUSIONS

Compared with hemodialysis, patients treated with peritoneal dialysis before transplantation had lower mortality but similar graft loss or delayed graft function. Confounding by residual selection bias cannot be ruled out.

Management of renal dysfunction in patients receiving a liver transplant

Renal dysfunction is a frequent complication in patients with endstage liver disease awaiting orthotopic liver transplantation. Although the stereotypical form of renal dysfunction is the hepatorenal syndrome, common causes of acute kidney injury include prerenal azotemia and acute tubular necrosis in this population. Management involves hemodynamic support, renal replacement therapy, and mitigation of risk factors. Renal dysfunction in a cirrhotic patient usually implies a poor prognosis in the absence of liver transplantation. An important issue is the frequent need for kidney, in addition to liver, transplantation if renal insufficiency has been persistent in a decompensated cirrhotic.