ORGAN DONATION AND ALLOCATION I

R.J. Johnson¹, S.V. Fuggle², L.L. Mumford¹, J.A. Bradley³, J.L.R. Forsythe⁴, C. Rudge^5
1Statistics And Clinical Audit, NHS Blood and Transplant (UK), Bristol/UNITED KINGDOM, ²Scientific Advisor, NHS Blood and Transplant (UK), Bristol/UNITED KINGDOM, ³Transplant Surgery, Addenbrooke's Hospital NHS Trust, Cambridge/UNITED KINGDOM, ⁴Transplant Unit, Royal Infirmary of Edinburgh, Edinburgh/UNITED KINGDOM, ⁵, Department of Health, London/UNITED KINGDOM

Body: Introduction The 2006 National Kidney Allocation Scheme (2006 NKAS) was introduced in the UK to improve equity of access to kidney transplantation while incorporating evidence-based factors to ensure no deterioration in transplant outcomes. The scheme had specific aims, primarily around equity of access (geography, rareness of HLA type, etc) and ensuring increased priority for long-waiting patients. In addition it was important that good HLA matching was retained for patients in whom it is important and that cold ischemia times (CIT) were minimised in a scheme that allocated all kidneys from donors after cardiac death (DCD) on a national basis for the first time in the UK. Approximately 900 kidneys per year are allocated from DCD to a waiting list of over 7000 patients. Methods The scheme prioritises all 000 HLA-A,B,DR mismatched (mm) patients and other well matched paediatric patients (100, 010, 110 HLA-A,B,DR mm). 75% of kidneys are allocated to remaining patients. Priority is primarily according to waiting time, and age combined with HLA mm (to ensure well matched transplants for younger patients). Other factors include donor-recipient age difference (to ensure old kidneys are not allocated to young patients and vice-versa which would waste valuable years of kidney life). Rare HLA antigens are ‘defaulted’ to more common counterparts to improve access for patients with rare HLA types. Results After almost 4 years of the 2006 NKAS, the proportion of patients on the list for over 5 years has dropped from 16% to 9%, with significant transplant centre variation much reduced. The transplant rate has increased in patients with rare HLA types: 17% of kidneys were previously allocated to ethnic minority patients compared with 23% more recently. To achieve these aims, strict HLA matching criteria have been relaxed while maximising 000 mm and avoiding poorly matched grafts altogether. Previously 20% of transplants were 000 mm (Level 1 mm) and 51% were Level 2 mm (100, 010, 110, 200, 210 mm). In the first year of the 2006 NKAS, 22% were Level 1 and 23% were Level 2. As long-waiting patients have been reduced, however, the levels of matching have increased again: 24% and 36% in the latest year. Levels of HLA mm differ with patient age as designed by the points scoring to facilitate retransplantation in younger patients: 71% Levels 1&2 mm in 18-29 year-olds compared with 34% in patients over 60 years. The excess of HLA-DR homozygous patients on the list has been eliminated (from 17% of the list to 14%). Median CIT has reduced from 17 hours to 16 hours. One year graft and patient survival rates are comparable with those seen previously (p=0.8 and 0.2, respectively). Conclusions The 2006 NKAS has been successful in improving equity of access to kidney transplantation in the UK. An excess of long-waiting patients on the list has been much reduced while well-matched grafts have been achieved for those in whom it is important.

Disclosure: All authors have declared no conflicts of interest.