Donor and recipient risk factors and choice of immunosuppression determine long-term outcome in renal transplantation.

Overview

MATERIALS AND METHODS

The Australian and New Zealand Dialysis and Transplantation Registry (ANZDATA Registry) in combination with the Australian and New Zealand Organ Donor Registry (ANZOD Registry) has collected outcome data on all renal transplant patients and their donors in the two countries (combined population now 23 million) since 1963. This database with 100% reporting and complete follow-up provides a unique opportunity to examine influences on outcome in reasonably large numbers of patients (total transplanted 1963 to 1999, 14,261 patients).1 All data in this paper are drawn from the databases of these two registries. It was arbitrarily decided to only study survivors at 5 years and beyond, in order to focus more clearly on factors operating in the long term, in patients receiving their transplant between the years 1970 and 1994. Follow-up was to death, graft failure, or to September 30, 2000. Before 1970, the numbers available for 0041-1345/01/$–see front matter PII S0041-1345(01)02465-4 3400 analysis were small and HLA matching was not performed. Cohort entry was limited to pre-1994 to allow for actual 5-year follow-up on all patients in the study. The analysis was confined to primary transplantation and included living and cadaver sourced kidneys. Only Australian-based patients were assessed for this study because it has been shown that this country has no center effect operating and approaches to clinical transplantation were believed to have been reasonably uniform through the years. The size of the cohorts beyond 5 years mostly allowed a 10- to 15-year follow-up to be assessed. Data points were truncated in all instances at the point where the cohort size reduced below 50 contributors. Outcomes studied were patient survival, patient survival (with a functioning graft) and graft survival (censored for patient death). The time-based cohorts were chosen arbitrarily but it should be noted that cyclosporine was introduced in Australia in 1984 and quickly became the basis for most immunosuppressive regimens.

RESULTS

The cohort transplanted between 1970 and 1994 in Australia with a primary renal transplant (living or cadaver donor) demonstrated an exponential decay in both the patient and graft survival between 1 and 20 years at a similar rate of 2.7% per year. Death-censored graft survival decayed at a rate of 1.8% per year.