Renal transplantation in the UK and Republic of Ireland.

RENAL TRANSPLANT OUTCOME: Analysis of 5-year transplant survival in the UK showed a number of significant factors influencing outcome of adult cadaveric renal transplantation. Data from 5,963 first grafts and 1,078 regrafts carried out between 1990-1997 showed year of graft, recipient age and diabetes, donor age, kidney exchange between centres and HLA matching to influence 5-year outcome. The most important prognostic factor was donor age: the risk of transplant failure within 5 years for grafts using kidneys from donors aged 60 years and over was double that of grafts using donors aged 18-34 years. Unlike the effect of donor age, the influence of HLA matching would appear to be diminishing with time. In contrast to transplants in the 1980's, the difference in 5-year transplant survival between 000 mismatched and favourably matched (100, 010 or 110 mismatched) transplants is no longer significant. An analysis of posttransplant survival for first grafts in different epochs (0-3 months, 3 months to 3 years and beyond 3 years) showed that one factor affected short-term outcome (exchange of kidneys between centres), whereas others affected outcome throughout the epochs (most notably donor age, recipient age and recipient diabetes). RECIPIENT AND DONOR AGE MATCHING: The mean recipient age in the UK and Republic of Ireland increased by 5 years between 1981-1990 but has remained at approximately 45 years since then. The mean donor age increased by 7 years to 42.5 years (s.e. 0.5) between 1981-1991 and since then has increased at a slower rate to 43.4 years (s.e. 0.5) in 1998. The mean donor-recipient age difference for more than 15,000 transplants carried out between 1990-1998 has decreased, primarily due to increasing donor age over this time. However, the introduction of a new Kidney Allocation Scheme in the UK in July 1998, part of which is aimed at minimising age differences, has increased the likelihood that recipients aged over 60 years will be allocated grafts from donors closer to their own age than previously. The new UK Kidney Allocation Scheme also gave children increased access to well-matched adult organs leading to an increased mean age difference for this group between July-December 1998. DONOR AND RECIPIENT HLA MATCHING: Modifications to the Kidney Allocation Scheme introduced in January 1997 with the aim of increasing the number of well-matched transplants has led to a rise in 000 mismatched grafts from 5% to 7% and favourably matched (100/010/110 mismatches) from 29% to 36% between 1990-1992 and 1996-1998. Over this same time the proportion of 2 DR-mismatched grafts has decreased from 10% to 4%. The revised Kidney Allocation Scheme implemented in July 1998 gave a further increase in priority to 000 mismatches, increasing the proportion of these transplants to 12% for the last half of 1998, a level which has been maintained since then.