Do pretransplant C-peptide levels predict outcomes following simultaneous pancreas-kidney transplantation? A matched case-control study

Bariatric surgery prior to pancreas transplantation: a retrospective matched case-control study

BACKGROUND

The clinical impact of bariatric surgery (BS) prior to pancreas transplantation (PTx) is unclear.

SETTING

University of Minnesota Hospital, Minneapolis, MN.

METHODS

This was a single center retrospective case-controlled study of all patients January 1, 1998 and May 1, 2024 with a history of BS prior to PTx. Patients were matched (1:3) with control patients by recipient age, body mass index (BMI) at PTx, type of transplant, primary versus retransplant, and year of PTx.

RESULTS

Among 1542 transplants, 17 patients had a history of BS prior to PTx, with an overall incidence of 1.1%. Eleven patients underwent roux-en-y gastric bypass, 5 underwent sleeve gastrectomy (SG), and one underwent vertical-banded gastroplasty. Eleven underwent simultaneous pancreas kidney transplant, 5 underwent pancreas transplant alone, and one underwent pancreas after kidney transplant. The median time (interquartile range [IQR]) between BS and PTx was 2.9 yrs (4.6) and ranged from .7 to 20.6 yrs. Compared to the non-BS group, patients in the BS group had similar rates of graft thrombosis (5.9% versus 3.9%, P = .76) and rejection (29.4% versus 29.4%, P > .99). Length of stay following PTx (P = .22), number of 30-day readmissions (P = .24), and number of 1-year readmissions (P = .70) were not different between the two groups. Median death-censored graft survival (9.4 yrs versus median not reached, P = .23) and patient survival (9.4 yrs versus median not reached, P = .18) were similar between the BS and non-BS groups. Finally, six patients underwent BS with the specific intention of reaching the acceptable BMI threshold for PTx. Median BMI was reduced from 37.4 prior to BS to 26.4 at time of PTx. Median time from BS to PTx was 2.4 yrs. At 4 yr follow-up, graft and patient survival was 100%.

CONCLUSIONS

This represents the largest series of patients with BS prior to PTx. Perioperative complications are not increased in patients undergoing PTx with a history of prior BS and long-term outcomes are equivalent. Patients with a prohibitive BMI for PTx eligibility should be considered for BS without concern for detrimental effect on post-transplant outcomes.

C-peptide Trajectory Following Pancreas Transplantation

BACKGROUND

Pancreas transplantation is the most reliable management of insulin-dependent diabetes mellitus, offering sustained glycemic control with a reduction in diabetes-related complications. Despite recent advancements, recipient selection criteria are not standardized. Historically, pre-transplant C-peptide level was an important indicator of post-transplant success, yet conflicting data exist regarding their correlation. This study explores post-transplant C-peptide trends in recipients with varying pre-transplant C-peptide levels, aiming to elucidate its impact on patient and graft survival.

METHODS

A retrospective review of 78 pancreas transplant recipients (simultaneous pancreas and kidney, pancreas after kidney, and pancreas transplant alone) from September 2012 to August 2022 was conducted. Patients were categorized based on pre-transplant C-peptide levels (>4.0 ng/mL elevated vs. ≤4.0 ng/mL low/normal). C-peptide levels, HbA1c, and estimated glomerular filtration rate (eGFR) were monitored at specified intervals post-transplant.

RESULTS

The two cohorts exhibited disparate post-transplant C-peptide trends; elevated (pre-transplant: mean = 8.43 ng/mL, range = 4-28.26 ng/mL; post-transplant: mean = 3.57 ng/mL, range = 0.84-8.53 ng/mL) and low/normal (pre-transplant: mean = 1.07 ng/mL, range = 0-3.92 ng/mL; post-transplant: mean = 2.81 ng/mL, range = 0.9-6.73 ng/mL). Despite achieving normoglycemic control (HbA1c 5.26% and 5.19%, respectively), the decline in C-peptide levels in the elevated pre-transplant group contradicted the anticipated outcomes.

CONCLUSION

This study highlights the intricate dynamics of post-transplant C-peptide, revealing unexpected patterns in recipients with elevated pre-transplant C-peptide levels. The study's findings question the predictive value of pre-transplant C-peptide levels and underscore the importance of further research to unravel its metabolism post-transplant.

Risk Factors for Early Post-transplant Weight Changes Among Simultaneous Pancreas-kidney Recipients and Impact on Outcomes

Background

There are limited data about the risk factors for weight changes and the association of significant weight changes with graft and metabolic outcomes after simultaneous pancreas and kidney (SPK) transplantation.

Methods

We included all SPK recipients with both allografts functioning for at least 6 mo post-transplant and categorized them based on the weight changes from baseline to 6 mo post-transplant. We analyzed risk factors for significant weight gain (SWG) and significant weight loss (SWL) over 6 mo post-transplant, as well as outcomes including pancreas uncensored graft failure, pancreas death-censored graft failure (DCGF), composite pancreas graft outcomes of DCGF, use of an antidiabetic agent, or hemoglobin A1C >6.5%, and kidney DCGF.

Results

Of 280 SPK recipients, 153 (55%) experienced no significant weight change, 57 (20%) SWG, and 70 (25%) SWL. At 6 mo post-transplant, mean weight changes were 1.2% gain in the no significant weight change group, 13.4% gain in SWG, and 9.6% loss in the SWL groups. In multivariate analysis, the only factor associated with decreased risk for weight gain was older recipient age (aOR, 0.97; 95% confidence intervals, 0.95-0.99). Importantly, SWG or SWL were not associated with pancreas graft failure, P-DCGF, or K-DCGF. Interestingly in the adjusted model, SWG at 6 mo was associated with a lower risk for composite outcomes (HR, 0.35; 95% confidence intervals, 0.14-0.85).

Conclusions

Forty-five percent of SPK recipients had significant weight changes by 6 mo post-transplant, but only 20% exhibited SWG. Likely because of proper management, weight changes were not associated with poor outcomes post-SPK transplant.

Generating strategies for a national comeback in pancreas transplantation: A Delphi survey and US conference report

In the United States, potential transplant candidates with insulin-dependent diabetes mellitus are inconsistently offered pancreas transplantation (PTx), contributing to a dramatic decline in pancreas allograft utilization over the past 2 decades. The American Society of Transplantation organized a workshop to identify barriers inhibiting PTx and to develop strategies for a national comeback. The 2-day workshop focused on 4 main topics: (1) referral/candidate selection, (2) organ recovery/utilization, (3) program performance/patient outcomes, and (4) enhanced education/research. Topics were explored through expert presentations, patient testimonials, breakout sessions, and strategic planning, including the identification of tasks for immediate focus. Additionally, a modified-Delphi survey was conducted among workshop members to develop and rate the importance of barriers, and the impact and feasibility of workgroup-identified improvement strategies. The panelists identified 16 barriers to progress and 44 strategies for consideration. The steps for a national comeback in PTx involve greater emphasis on efficient referral and candidate selection, better donor pancreas utilization practices, eliminating financial barriers to procurement and transplant, improving collaboration between transplant and diabetes societies and professionals, and increasing focus on PTx training, education, and research. Partnership between national societies, patient advocacy groups, and professionals will be essential to realizing this critical agenda.

Higher Fasting Pretransplant C-peptide Levels in Type 2 Diabetics Undergoing Simultaneous Pancreas-kidney Transplantation Are Associated With Posttransplant Pancreatic Graft Dysfunction

BACKGROUND

Among selected patients with type 2 diabetes mellitus (T2DM), simultaneous pancreas and kidney (SPK) transplants can be an effective option. However, data are limited about outcomes in T2DM SPK recipients based on the pretransplant C-peptide levels.

METHODS

In this study, we reviewed all T2DM SPK recipients and categorized them based on the pretransplant fasting C-peptide levels into 3 groups: low (≤2 ng/mL), medium (>2-8 ng/mL), and high (>8 ng/mL). Several measures of graft failures (GFs), graft dysfunction, and composite outcomes were of interest.

RESULTS

There were a total of 76 SPK recipients (low, n = 14; medium, n = 47; high, n = 15). At the last follow-up, the low group did not reach any outcome; in contrast, 11 (23%) in the medium group and 5 (33%) in the high group reached the uncensored composite outcome; 6 (13%) in the medium group and 2 (13%) in the high group had GF; and 8 (17%) in the medium group and 4 (26.7%) in the high group reached the death-censored composite outcomes. In a fully adjusted model, each pretransplant C-peptide unit was not associated with an increased risk of the composite outcome, GF, or death-censored composite outcomes. However, in multivariate analysis with limited adjustment, pretransplant C-peptide was associated with the composite outcome (hazard ratio: 1.18, 95% confidence interval, 1.01-1.38; P = 0.03) and death-censored composite outcome (hazard ratio: 1.20; 95% confidence interval, 1.01-1.42; P = 0.03).

CONCLUSIONS

Although limited by the small sample size, we found excellent outcomes among T2DM SPK recipients overall. However, higher levels of pretransplant C-peptide may be associated with inferior posttransplant outcomes that include graft dysfunction.