Long-term prognosis in kidney transplant recipients depends on multiple factors. The purpose of this study was to quantify the influence of hyperuricemia and hyperglycemia (elements of the so-called 'syndrome X', i.e., a combination of metabolic disorders like hyperuricemia, diabetes mellitus, hyperlipidemia, and hypertension) on organ function in 350 kidney transplant recipients who had received 375 kidney transplants up to 1990 and in whom sex, age of recipient and donor, nephrologic disease, duration of dialysis, human leukocyte antigen (HLA) classification, and duration of transplant ischemia had been well matched. We found the influence of hyperuricemia on graft survival to be statistically significant (p < or = 0.05), while a statistically significant correlation between hyperglycemia and graft survival could not be detected in the present study. The transplant survival rates 2, 4, and 5 yr post-kidney-transplantation were 96.7, 80.7, and 78.7 in normogylcemic patients vs. 96.9, 85, and 82.7% in hyperglycemic ( > 100 mg,dL) kidney transplant recipients (p > 0.05). Transplant survival in hyperuricemic patients (male, > 8 mg dL; female, > 6.2 mg/dL) 2, 4, and 5 yr post-transplantation was significantly reduced (92.2, 70.6, and 68.8% vs. 98.1, 85.6, and 83.3%), as compared to normouricemic recipients. A combined presence of both hyperuricemia and hyperglycemia probably influencing the prognosis post-kidney-transplantation failed to reach the level of statistical significance. We found a significant correlation between age of recipients and plasma glucose (p < or = 0.01) and between serum uric acid concentrations and diuretic therapy (p < or = 0.05) and gender (p < or = 0.(5). In conclusion, hyperuricemia after kidney transplantation seems to reduce graft survival, whereas an influence of the carbohydrate metabolism has to be denied.