Simultaneous Pancreas-Kidney Versus Deceased Donor Kidney Transplant: Can a Fair Comparison be Made?

Race does not predict pancreas graft failure after pancreas transplantation in the Modern Era

BACKGROUND

African-American (AA) has historically been associated with inferior graft survival after pancreas transplantation. However, with the improvement of immunosuppression and surgical technique, we hypothesized that the racial disparity has been neutralized.

METHODS

We analyzed data from the Scientific Registry of Transplant Recipients (1989-2018). Using Kaplan-Meier estimation and Cox proportional hazards regression, we examined the influence of race on pancreatic graft survival.

RESULTS

Before 2009, AA recipients had a higher risk of pancreatic graft failure after adjusting for confounding factors (hazard ratio [HR]: 1.16, 95% confidence interval [CI]: 1.08-1.24), but the risks for Hispanic and Asian recipients were both comparable to their Caucasian counterparts. However, the risk of pancreatic graft failure in AA recipients dropped to 1% and was no longer significant since 2009 (HR: 1.01, 95%CI: 0.88-1.16). Interestingly, donor race showed similar results. Furthermore, the concordance statistic of the complete pancreas donor risk index (including donor race) was 0.582, whereas the concordance did not change when donor race was eliminated from the model.

CONCLUSIONS

AA and other races have shown similar pancreatic graft survival in the modern era. Furthermore, donor racial disparity also seems neutralized; thus, donor race should not be considered as an indicator of pancreatic donor quality. This article is protected by copyright. All rights reserved.

Metabolic outcomes and renal function after simultaneous kidney/pancreas transplantation compared with kidney transplantation alone for type 2 diabetes mellitus patients

In this study, we aimed to compare the metabolic outcomes, renal function, and survival outcomes of simultaneous pancreas and kidney transplantation (SPK) and kidney transplantation alone (KTA) among end‐stage kidney disease (ESKD) patients with type II diabetes mellitus (T2DM). Patients with ESKD and T2DM who underwent KTA (n = 85) or SPK (n = 71) in a transplant center were retrospectively reviewed. Metabolic profiles, renal function, and survival outcomes were assessed repeatedly at different follow‐up time points. Propensity score procedures were applied to enhance between‐group comparability. The levels of renal and metabolic outcomes between SPK and KTA over time were examined and analyzed using mixed‐model repeated‐measures approaches. The median follow‐up period was 1.8 years. Compared with KTA, SPK resulted in superior metabolic outcomes and renal function, with lower levels of glycated hemoglobin (HbA1c; P = 0.0055), fasting blood glucose (P < 0.001), triglyceride (P = 0.015), cholesterol (P = 0.0134), low‐density lipoprotein (P = 0.0161), and higher estimated glomerular filtration rate (eGFR; P < 0.001). SPK provided better metabolic outcomes and renal function. The survival outcomes of the recipients and grafts were comparable between the two groups.

Defining kidney allograft benefit from successful pancreas transplant: separating fact from fiction

PURPOSE OF REVIEW

To define the natural history of kidney allograft loss related to recurrent diabetes following transplant, and to understand the potential benefit of pancreas transplantation upon kidney allograft survival.

RECENT FINDINGS

A postulated benefit of simultaneous pancreas kidney transplant is that, unlike kidney transplant alone, euglycemia from the added pancreas allograft may confer a nephroprotective benefit and prevent recurrent diabetic nephropathy in the renal allograft. Recent large database analyses and long-term histological assessments have been published that assist in quantifying the problem of recurrent diabetic nephropathy and answering the question of the potential benefits of euglycemia. Further data may be extrapolated from larger single-center series that follow the prognosis of early posttransplant diabetes mellitus as another barometer of risk from diabetic nephropathy and graft loss.

SUMMARY

Recurrent diabetic nephropathy following kidney transplant is a relatively rare, late occurrence and its clinical significance is significantly diminished by the competing risks of death and chronic alloimmune injury. Although there are hints of a protective effect upon kidney graft survival with pancreas transplant, these improvements are small and may take decades to appreciate. Clinical decision-making regarding pancreas transplant solely based upon nephroprotective effects of the kidney allograft should be avoided.

Long-Term Outcomes of Kidney and Simultaneous Pancreas-Kidney Transplantation in Recipients With Type 1 Diabetes Mellitus: Silesian Experience

BACKGROUND

Kidney transplantation (KTx) markedly reduces mortality in patients with end-stage kidney disease (ESKD) caused by type 1 diabetes mellitus (T1DM). The outstanding issue is whether transplantation should be limited only to KTx, with further insulinotherapy, or combined with pancreas transplantation in patients with ESKD/T1DM. The goal of this study was to compare the results of simultaneous pancreas-kidney transplantation (SPKTx) and deceased donor KTx and to identify factors affecting patient and kidney graft survival in patients with ESKD/T1DM.

METHODS

Eighty-seven deceased donor KTx and 66 SPKTx operated on in the Silesia region of Poland between 1998 and 2013 were included in the retrospective analysis.

RESULTS

During the mean 6.7 ± 3.6 years of follow-up, fewer cardiovascular episodes were observed in SPKTx recipients than in KTx recipients (1.5% vs 12.6%; P < .05). Five-year patient survival (80.7% in SPKTx vs 77.5% in KTx) and kidney graft survival (66.1% in SPKTx vs 70.4% in KTx) did not differ between study groups. There were no differences in patient survival (log-rank test, P = .99) or kidney graft survival (P = .99) based on Kaplan-Meier curves. Multivariable Cox proportional hazard analysis failed to identify factors explaining patient and kidney graft survival. Five-year pancreas graft survival was 58.9%. SPKTx recipients had significantly higher estimated glomerular filtration rates during the 7-year posttransplant period and less frequently developed proteinuria (6.1% vs 23%; P < .01).

CONCLUSIONS

Pancreas transplantation reduced cardiovascular risk and prevented the development of proteinuria but did not improve patient and kidney graft survival in recipients with T1DM in the 7-year follow-up period.

Challenges in pancreas transplantation

Whole-organ pancreas transplantation, either alone or combined with a kidney transplant, is the only definitive treatment for many patients with type 1 diabetes that restores normal glucose homoeostasis and insulin independence. Pancreas transplantation delays, or potentially prevents, secondary diabetes complications and is associated with improvement in patient survival when compared with either patients remaining on the waiting list or those receiving kidney transplant alone. Pancreas transplantation is safe and effective, with 1-year patient survival >97 % and graft survival rates of 85 % at 1 year and 76 % at 5 years in recent UK data. This review focuses on some current areas of interest in pancreas transplantation.

Kidney transplant options for the diabetic patient

For patients with diabetes and progressive chronic kidney disease, kidney transplantation is the optimal mode of renal replacement therapy, with or without a pancreas transplant. Additional benefits of pancreas transplant have become increasingly apparent due to advances in surgical outcomes and immunosuppression, and may be reasonably considered even in selected patients with type 2 diabetes. In general, pancreas transplantation is associated with long-term survival advantages despite an increased short-term morbidity and mortality risk. This is true with simultaneous pancreas kidney transplantation or pancreas after kidney transplantation compared to kidney transplantation alone, regardless of kidney donor status (living or deceased). Individual patient preferences, comorbidities, and expected waiting time influence selection of transplant modality, rather than a clear survival benefit of one strategy versus the other. In selected patients with type 2 diabetes, recent outcomes data support cautious utilization of simultaneous pancreas kidney transplantation when a living kidney donor transplant is not an option. The purpose of this review is to summarize current data regarding kidney and pancreas transplant treatment options in patients with both type 1 and 2 diabetes and the influence of current organ allocation policies to better understand the advantages and disadvantages of each of these strategies.

Simultaneous pancreas kidney transplant versus other kidney transplant options in patients with type 2 diabetes

BACKGROUND AND OBJECTIVES

Current organ allocation policy prioritizes placement of kidneys (with pancreas) to patients listed for simultaneous pancreas-kidney transplantation (SPK). Patients with type 2 diabetes mellitus (T2DM) may undergo SPK, but it is unknown whether these patients enjoy a survival advantage with SPK versus deceased-donor kidney transplantation alone (DDKA) or living-donor kidney transplantation alone (LDKA).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the Scientific Registry of Transplant Recipients database, patients with T2DM, age 18-59 years, body mass index 18-30 kg/m(2), who underwent SPK, DDKA, or LDKA from 2000 through 2008 were identified. Five-year patient and kidney graft survival rates were compared, and multivariable analysis was performed to determine donor, recipient, and transplant factors influencing these outcomes.

RESULTS

Of 6416 patients identified, 4005, 1987, and 424 underwent DDKA, LDKA, and SPK, respectively. On unadjusted analysis, patient and kidney graft survival rates were superior for LDKA versus SPK, whereas patient but not graft survival was higher for SPK versus DDKA. On multivariable analysis, survival advantage for SPK versus DDKA was related not to pancreas transplantation but younger donor and recipient ages in the SPK cohort.

CONCLUSIONS

Good outcomes can occur with SPK in selected patients with T2DM, but no patient or graft survival advantage is provided by added pancreas transplantation compared with DDKA; outcomes were superior with LDKA. These results support cautious use of SPK in T2DM when LDKA is not an option, with close oversight of the effect of kidney (with pancreas) allocation priority over other transplant candidates.

Does simultaneously transplanted pancreas improve long-term outcome of kidney transplantation in type 1 diabetic recipients?

INTRODUCTION

Simultaneous pancreas-kidney transplantation (SPK) is an alternative to kidney transplantation (KTx) for type 1 diabetic patients with end-stage kidney disease. However, a fair comparison of SPK and KTx is difficult because of significant differences in donor, recipient, and transplantation procedure parameters. The aim of this study was to compare the early and long-term outcomes of SPK versus KTx in southwest Poland.

MATERIAL AND METHODS

Thirty-five diabetic dialysis patients who had SPK and 64 patients who had KTx were included in the analysis.

RESULTS

SPK recipients were younger (38±6 years versus 42±9 years) and received organs from younger donors (25±7 versus 43±12 years) compared to the KTx group. They had shorter kidney cold ischemia time (9±2 hours versus 22±7 hours) but worse HLA class II mismatches (1.4±0.6 versus 1.0±0.5). In the early postoperative period, three patients died from the SPK group and one patient died from the KTx group. Additionally, two SPK patients lost their pancreatic grafts, and five KTx patients lost their kidney grafts. One-year patient survival rates for the SPK and KTx groups were 88% and 98%, respectively, and 5-year, 81% and 93%, respectively. One-year kidney graft survivals rates for the SPK and KTx groups were 100% and 89%, respectively, and 5-years, 89% and 81%, respectively. One-year insulin-free survival among SPK patients was 90% and the 5-year survival rate was 76%. Excretory function of the transplanted kidneys was better among SPK group; however, the difference reached statistical significance only in posttransplant years 2 and 3: 63.5±20.1 versus 50.3±19.7 and 64.9±12.9 versus 51.6±21.8 mL/min/1.73 m2 for SPK and KTx, respectively.

CONCLUSIONS

Normoglycemia in SPK recipients did not improve patient survival at 5 years. The worse HLA compatibility in the SPK group did not lead to impaired kidney graft survival compared to KTx. Better kidney graft function among SPK recipients probably resulted from a more restrictive donor selection.

The time interval between kidney and pancreas transplantation and the clinical outcomes of pancreas after kidney transplantation

Pancreas after kidney (PAK) transplantation is one of the accepted pancreas transplant modalities. We studied the impact of time interval between kidney and pancreas transplantation on the outcomes of PAK transplantation. Using OPTN/SRTR data, we included 1853 PAK transplants performed between 1996 and 2005 with follow-up until November 1, 2008. Kaplan-Meier survival and multivariate Cox regression analyses were performed using the time interval between kidney and pancreas transplantation either as a categorical (less than one yr, between one and less than three yr, and greater than or equal to three yr) or as a continuous variable (months) to assess kidney graft and patient survival. Patients who received a pancreas transplant three yr or later after kidney transplantation had higher risk of death-censored kidney graft loss (HR 1.56, 95% CI 1.04, 2.32, p = 0.03). Each month beyond three yr between kidney and pancreas transplantation incurred 1% higher risk of subsequent death-censored kidney graft loss (HR 1.01, 95% CI 1.001, 1.02, p = 0.03). In conclusion, time interval between pancreas and kidney transplantation is an independent risk factor of kidney graft loss following pancreas transplantation. Shortening the time interval between pancreas and kidney transplantation to less than three yr may reduce the risk of kidney graft loss in qualified PAK transplant candidates.

Evolution of β-Cell Replacement Therapy in Diabetes Mellitus: Pancreas Transplantation

Diabetes mellitus remains one of the leading causes of morbidity and mortality worldwide. According to the Centers for Disease Control and Prevention, approximately 23.6 million people in the United States are affected. Of these individuals, 5-10% have been diagnosed with type 1 diabetes mellitus (TIDM), an autoimmune disease. Although it often appears in childhood, T1DM may manifest at any age. The effects of T1DM can be devastating, as the disease often leads to significant secondary complications, morbidity, and decreased quality of life. Since the late 1960s, surgical treatment for diabetes mellitus has continued to evolve and has become a viable alternative to chronic insulin administration. In this review, the historical evolution, current status, graft efficacy, benefits, and complications of pancreas transplantation are explored.

The role of kidney-pancreas transplantation in diabetic kidney disease

For patients with type 1 diabetes, innovations in insulin formulations and delivery have improved the ability to achieve excellent blood glucose control. However, it is uncommon to achieve euglycemia, particularly while avoiding complications arising from hypoglycemia. Pancreas transplantation remains the only broadly applied treatment strategy that can result in normalization of blood glucose, but this must be weighed against the risks of a surgical procedure and subsequent immunosuppression. To improve this risk/benefit ratio, pancreas transplantation is typically performed in patients with kidney failure who are to undergo kidney transplantation and immunosuppression (simultaneous pancreas-kidney transplant) or who have undergone kidney transplant and are obligated to the use of immunosuppressive medications (pancreas after kidney transplant). The purpose of this review is to clarify the benefit of an added pancreas transplant in these clinical settings and formulate an approach to the patient with type 1 diabetes as they approach kidney failure.

Influence of recipient race on the outcome of simultaneous pancreas and kidney transplantation

Racial differences on the outcome of simultaneous pancreas and kidney (SPK) transplantation have not been well studied. We compared mortality and graft survival of African Americans (AA) recipients to other racial/ethnic groups (non-AA) using the national data. We studied a total of 6585 adult SPK transplants performed in the United States between January 1, 2000 and December 31, 2007. We performed multivariate logistic regression analyses to determine risk factors associated with early graft failure and immune-mediated late graft loss. We used conditional Kaplan-Meier survival and multivariate Cox regression analyses to estimate late death-censored kidney and pancreas graft failure and death between the groups. Although there was no racial disparity in the first 90 days, AA patients had 38% and 47% higher risk for late death-censored kidney and pancreas graft failure, respectively (p = 0.006 and 0.001). AA patients were twice more likely to lose the kidney and pancreas graft due to rejection (OR 2.31 and 1.86, p = 0.002 and 0.008, respectively). Bladder pancreas drainage was associated with inferior patient survival (HR 1.42, 95% CI 1.15, 1.75, p = 0.001). In the era of modern immunosuppression, AA SPK transplant patients continue to have inferior graft outcome. Additional studies to explore the mechanisms of such racial disparity are warranted.

Pancreas transplantation in the United States: a review

PURPOSE OF REVIEW

The goal of pancreas transplantation is to restore normoglycemia in patients with labile diabetes. The results of this procedure improved over the years, but, although pancreas transplantation is not considered experimental anymore, there is often reluctance to recommend this procedure because of the complexity, especially for solitary pancreas transplants. This article reviews the current status of pancreas transplantation.

RECENT FINDINGS

Many improvements have been made in the surgical techniques and immunosuppressive regimens. The overall rate of technical problems decreased, yet immunologic graft loss is still a problem in solitary pancreas transplants. Careful donor selection significantly decreased the risk of graft failure and therefore improved patient survival.

SUMMARY

With modern immunosuppressive protocols and careful donor selection, patient survival rates and pancreas transplant graft function can be further improved in all three pancreas transplant categories.

Kidney transplant in diabetic patients: modalities, indications and results

BACKGROUND

Diabetes is a disease of increasing worldwide prevalence and is the main cause of chronic renal failure. Type 1 diabetic patients with chronic renal failure have the following therapy options: kidney transplant from a living donor, pancreas after kidney transplant, simultaneous pancreas-kidney transplant, or awaiting a deceased donor kidney transplant. For type 2 diabetic patients, only kidney transplant from deceased or living donors are recommended. Patient survival after kidney transplant has been improving for all age ranges in comparison to the dialysis therapy. The main causes of mortality after transplant are cardiovascular and cerebrovascular events, infections and neoplasias. Five-year patient survival for type 2 diabetic patients is lower than the non-diabetics' because they are older and have higher body mass index on the occasion of the transplant and both pre- and posttransplant cardiovascular diseases prevalences. The increased postransplant cardiovascular mortality in these patients is attributed to the presence of well-known risk factors, such as insulin resistance, higher triglycerides values, lower HDL-cholesterol values, abnormalities in fibrinolysis and coagulation and endothelial dysfunction. In type 1 diabetic patients, simultaneous pancreas-kidney transplant is associated with lower prevalence of vascular diseases, including acute myocardial infarction, stroke and amputation in comparison to isolated kidney transplant and dialysis therapy.

CONCLUSION

Type 1 and 2 diabetic patients present higher survival rates after transplant in comparison to the dialysis therapy, although the prevalence of cardiovascular events and infectious complications remain higher than in the general population.