Factors contributing for improved graft survival in recipients of kidney transplants

We analyzed the survival results of 300 consecutive kidney transplants (TXs) performed at Hennepin County Medical Center, Minneapolis, Minnesota, between March 1965 and April 1980. The graft survival result were compared between three sequential time periods, each comprising 100 renal TXs. The proportion of live donor TXs decreased from 27% in period 1 to 16% in period 2 and 5% in period 3, while the number of older patients, diabetic and multiple TX patients increased steadily. A comprehensive patient care scheme utilizing clinical protocols was developed in period 2 and carried out effectively in period 3. The Cox multivariate regression models used in this analysis allowed us to assess the influence of each variable on the graft survival results, while the effects of all others were held constant. Among the nondiabetic patients who received antilymphocyte globulin, the 1 and 5 year graft survival rates were 59.7 and 38.8% in period 1, 85.3 and 74.3% in period 2, 90.4 and 83.1% in period 3 (periods 1 versus 2: P = 0.008, periods 1 versus 3: P less than 0.0001). This improvement in graft survival was independent of the effects of the following variables, that is, the recipient's age, donor source, prior dialysis, co-existing medical problems, splenectomy, previous TXs, blood transfusions, cytotoxic antibodies, cold ischemia time, HLA mismatches, and post-TX acute tubular necrosis. Our observations indicate that reduced immunosuppression, frequent use of biopsy specimens and comprehensive patient care, played an important role in minimizing the loss of renal transplants in the later time periods and contributed indirectly for the improved graft survival results of our institution.