Transplantation of the type 1 diabetic patient: the long-term benefit of a functioning pancreas allograft.

A lthough simultaneous pancreas-kidney transplantation (SPK) is generally believed to be the treatment of choice in type 1 diabetic patients with kidney failure, there is continuing controversy whether SPK is superior to kidney transplantation alone (KTA), especially when a live donor kidney (LDK) is available. This controversy is highlighted by three recent publications authored by Young et al. (1), Weiss et al. (2), and our group (3). Analyzing data from large registries, all three studies compared kidney graft and patient survival in SPK (all from deceased organ donors) and KTA transplants, whereby the KTA grafts were from deceased (DDK) or living donors (LDK). The three studies are summarized in Table 1 (bold) with respect to data source, treatment modality, length of follow-up, and patient and kidney graft survival. Young et al. and Weiss et al. analyzed U.S. data based on the Organ Procurement and Transplantation Network/ United Network for Organ Sharing and the Scientific Registry of Transplant Recipients, respectively. Young and colleagues found superior kidney graft and patient survival in LDK recipients as compared with SPK recipients after a maximum of 7 years of follow-up. No significant difference was found between deceased donor SPK and DDK patients with respect to kidney graft and patient survival. In contrast, analyzing the international Collaborative Transplant Study (CTS) database, which collects data from 46 countries in five continents, our group found that SPK and LDK yielded clearly superior kidney graft and patient survival as compared with DDK alone. Importantly, in the CTS analysis, patient survival beyond year 10 after transplantation in SPK recipients was significantly better than that of recipients of a LDK without a pancreas graft (hazard ratio 0.55; P 0.005), as demonstrated for transplants performed between 1984 and 1990 with a follow-up of 18 years. This effect was mainly attributable to a significantly lower rate of cardiovascular death in recipients of a combined pancreas-kidney transplant (SPK 37.0% versus DDK 45.8%, P 0.049; and versus LDK 49.3%, P 0.007). The univariate results were confirmed by multivariate analysis, in which it was taken into account that SPK patients are commonly in a better physical condition at the time of transplantation; that is, with less pre-existing cardiovascular disease than DDK recipients. Our data are supported by the analysis of Weiss and coworkers who found superior kidney graft and patient survival in type 1 diabetic SPK recipients who had a functioning pancreas allograft 12 months posttransplantation, as compared with SPK patients who had lost their pancreas allograft within the first year after transplantation, but also in comparison to type 1 diabetic LDK and DDK recipients (2). These data support the benefit of a functioning pancreas allograft. The three studies end up with three different results and therefore lead to different recommendations. Weiss and coworkers actually made no recommendation at all. Young and colleagues made a priority recommendation for LDK in type 1 diabetic patients, whereas our group favored SPK as a first line treatment option for type 1 diabetics. Because the recommendations are so different, critical analysis and comment is warranted.