Modelling the benefits and costs of integrating an acceptable HLA mismatch allocation model for highly-sensitised patients

Wai Lim¹, Hung Do Nguyen¹, Germaine Wong^2,3, Kirsten Howard², Frans Claas⁴, Jonathan Craig^2,3, Samantha Fidler⁵, Lloyd D'Orsogna⁵, Jeremy Chapman³, Ashley Irish⁶, Paolo Ferrari⁷, Frank Christiansen⁵

¹Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia, ²Sydney School of Public Health, The University of Sydney, Sydney, Australia, ³Centre for Kidney Research, The Children’s Hospital at Westmead & Centre for Transplant and Renal Research, Westmead Hospital, Sydney, Australia, ⁴Eurotransplant Reference Laboratory, Department Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, Netherlands, ⁵Department of Clinical Immunology, Royal Perth Hospital, Perth, Australia, ⁶Department of Renal Medicine, Royal Perth Hospital, Sydney, Australia, ⁷Department of Renal Medicine, Fremantle Hospital, Perth, Australia

Background: The Eurotransplant acceptable mismatch program has improved transplantation access for highly-sensitised recipients. However, the benefits and costs of implementing such a program remain unknown.

Methods: Using decision analytical modelling, we compared the average waiting time for transplantation, overall survival gains (in life-years and quality-adjusted life-years gained) and costs of integrating an acceptable mismatch allocation model compared with the current deceased-donor kidney allocation model in Australia.

Results: Acceptable mismatches were identified in 12 of 28 (43%) highly-sensitised recipients using HLAMatchmaker. Inclusion of acceptable mismatches in the current allocation model improved the transplantation access for 4 (14%) highly-sensitised recipients, with an average reduction in waiting time of 34 months (from 86 to 52 months). Compared with the current allocation model, incorporating an acceptable mismatch allocation model achieved an overall lifetime gain of 0.034 quality-adjusted life-years and savings of over $4,000 per highly-sensitised patient, with a small consequential loss of 0.005 quality-adjusted life-years and extra costs of  $800 for every reallocated patient.

Conclusions: Despite modest overall health gains, application of an acceptable mismatch allocation model is an equitable approach to improve transplantation access for highly-sensitised transplant candidates without compromising the overall health benefits among the other patients on the deceased-donor waitlist in Australia.