Evaluation of the cost-effectiveness of sirolimus versus cyclosporin for immunosuppression after renal transplantation in the United Kingdom

Objective: The purpose of this study was to evaluate the cost-effectiveness of sirolimus compared with cyclosporin for the postsurgical management of renal transplant recipients, from the perspective of the UK National Health Service and the Personal Social Service. Methods: A discrete event stochastic simulation model was developed to evaluate both cost-effectiveness and cost utility over 10 and 20 years after transplant using historical data on 937 renal transplant recipients from the University Hospital of Wales in Cardiff, United Kingdom. The simulation was designed to forecast the incidence of acute rejection events, graft failure, retransplant, frequency of hemodialysis (HD) and peritoneal dialysis (PD), and death. Cox proportional hazard models were derived from historical transplant data, in which 1-, 2-, and 3-year post-transplant serum creatinine levels were used as the key drivers for predicting graft success and survival. Costs were reported as year-2003 UK pounds sterling (1 pound approximate to US $1.76). Probabilistic sensitivity analysis was conducted and results reported with particular attention to 2 threshold values, 30,000 pound/QALY and 20,000 pound/QALY. Results: Over a 10-year time horizon, treatment with sirolimus was projected to produce a gain of 0.60 discounted year of functioning graft with a cost savings of 276 pound per patient. Over a 20-year time horizon, these benefits increased to 1.59 discounted years of functioning graft and a cost savings of 7405 pound per patient. Using sensitivity analysis of the 10-year model, the only factors found to cause the probability of exceeding a 30,000 pound ceiling to be > 5% were the proportion of subjects maintaining continuous graft function and the use of low-dose cyclosporin. With the 20-year model, sirolimus maintained cost-effectiveness across most scenarios in sensitivity analysis. Conclusions: In this model analysis, sirolimus was cost-effective compared with cyclosporin for 10 to 20 years after renal transplantation in the United Kingdom, from the perspective of the UK National Health Service and Personal Social Service.