268 The Impact of Center Volume on Outcome of Pancreas Transplants
Monday November 16, 2015 from 11:00 to 12:30
Room 110

Angelika C. Gruessner, United States

Professor of Public Health

Mel and Enid College of Public Health

University of Arizona


The Impact of Center Volume on Outcome of Pancreas Transplants

Angelika Gruessner1, Rainer W Gruessner1.

1College of Public Health, University of Arizona, Tucson, AZ, United States

Introduction: The number of pancreas transplants has continuously declined in the US over the last decade: just between 1/1/2009 and 12/31/2014 the overall number of pancreas transplant declined by 16%. Simultaneous Pancreas and Kidney transplants (SPKs) declined by 11% and Pancreas after Kidney transplants (PAKs) by 46% - only the number of Pancreas Transplants Alone (PTAs) has remained stable. Since the number of transplant centers that perform pancreas transplants has remained constant the number of transplants per center has decreased. In contrast, the number of kidney transplants has not changed during the same time period.
Purpose: This study examines the impact of pancreas and kidney transplant volume per center on patient and graft survival.
Methods: We analyzed all 6,060 pancreas transplants reported to UNOS and IPTR that were performed in diabetic patients at 138 centers between 1/1/2009 and 12/31/2014. The majority were SPKs (78%) followed by PAKs (14%) and PTAs (8%). Only 7% of pancreas transplants were retransplants. Mean center pancreas transplant volume ranged from 1 to 43 pancreas transplant/year. At the same time the kidney transplant volume for those centers which also performed pancreas transplants ranged between from 21 to 253 kidney transplants/year. Center volume was categorized into low, medium and high by tertiles of the distribution of transplant volume. The cut points are on average 4 or 8 pancreas transplants/year and 67 or 119 kidney transplants/year. Comprehensive univariate and multivariate analyses were performed to assess the impact of center volume on outcome.
Results: There is a strong correlation between pancreas and kidney transplant center volume (p<0.0001): high volume pancreas transplant programs are also more likely to have high volume kidney transplant programs. Overall more than half of the pancreas transplants (68%) were performed at high volume and only 14% at low volume centers. High volume programs were more likely to perform PTAs (86%) then low or medium sized programs (p<0.0001).
There was a trend at low volume centers to choose low risk recipients and better donors. During this 6-year time period overall patient survival was excellent with over 93% survival rates at 3 years post-transplant irrespective of center volume. Only in PTAs was a less favorable patient survival rate noted at small and medium volume centers (p=0.08). Overall pancreas and kidney graft survival rates were superior in high and medium volume centers (p=0.03). Table 1 shows the result of a multivariate analysis of primary pancreas graft function in comparison to low volume centers adjusted for patient and donor factors. The multivariate analysis confirmed our univariate results. Moreover, outcome of retransplants was significantly better when performed at high volume centers.
Of note, the size of the kidney transplant program had no impact on the outcome of pancreas graft function but showed a favorable impact on outcome in patient survival.
Conclusions: The following 2 conclusions can we drawn from this large IPTR/UNOS database analysis: (1) while there are hardly any differences in patient survival according to pancreas center volume, pancreas graft survival is significantly higher at high and medium volume centers vs. low volume centers; (2) the volume of the concurrent kidney transplant program showed an additional favorable impact on patient but not on pancreas graft survival. This may indicate that specific pancreas transplant experience for optimal treatment of pancreas recipients is required.

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