Recent reports have demonstrated an improved cardiovascular outcome after simultaneous pancreas-kidney transplantation (SPKT) compared with kidney transplantation alone (KTA) in type 1 diabetic patients with end-stage renal disease. The purpose of this study was to determine the impact of SKPT and KTA on the progression of cerebrovascular disease (CVD), coronary heart disease (CHD) and peripheral vascular disease (PVD) 5 and 10 years after transplantation. Only patients with graft survival more than 5 years, were included in this study. In summary, 12 type 1 diabetic patients with SPKT and 10 diabetic subjects with KTA were evaluated. The immunosuppressive therapy was similar in both patient groups. The mean observation period was 124 (72-184) months in the SPKT group and 122 (64-216) months in the group with KTA. To investigate the vascular risk profile we examined mean HbA1c, blood pressure and lipid levels in both patient groups during the first 5 years (period I) and the second 5 years (period II) after transplantation (measurements at least at 3-month intervals). Additionally, we evaluated the prevalence of moderate (stage I-II) and severe (stage III-IV) macrovascular diseases prior as well as 5 and 10 years after transplantation. During period I the mean HbA1c-value was 5.7+/-0.4% in the group with SPKT versus 7.4+/-0.8% in the KTA group, and in period II 5.8+/-0.4% in the SPKT group versus 7.6+/-0.9% (P<0.001) in the patients with KTA. The cholesterol levels were approximately the same in both groups, the triglycerides were lower in the patients with SPKT than in the subjects with KTA with 1.3+/-0.4 vs. 2.2+/-0.9 mmol/l in period I, and 1.4+/-0.5 vs. 2.3+/-0.6 mmol/l in period II (P<0.05). The BP-values were similar in both groups. Five years after transplantation the prevalence of vascular diseases was not significantly different between both groups. During the following 5 years the prevalence of macrovascular diseases increased more in the KTA than in the SKPT group. After a mean observation period of 10 years the SKPT group showed a lower prevalence of vascular diseases (stage I-IV) with 41% CVD, 50% CHD and 50% PAV in comparison to the KTA group with a prevalence of 80% CVD, 90% CHD and 80% PAV), the difference was not statistically significant because of the small patient groups. The frequency of the vascular complications myocardial infarction (16% vs. 50%), stroke (16% vs. 40%) and amputations (16% vs. 30%) was in summary significant lower in the patients with SPKT than in the patients with KTA (P<0.05). In conclusion, while for the first 5 years after transplantation the progression of macroangiopathy in patients with SPKT and KTA was not significantly different, after a mean 10-year observation period the progression of macrovascular diseases was significantly lower in recipients with a functioning SPKT compared to patients with a KTA; this can be explained by a better vascular risk profile after SPKT. The 10-year patient survival was 83% in the SPKT group and 70% in patients with KTA.