Treatment of multiple sclerosis with interferon beta: an appraisal of cost-effectiveness and quality of life.

OBJECTIVE To evaluate the cost-effectiveness of interferon beta-1b (IFbeta-1b) for relapsing-remitting multiple sclerosis (RRMS). METHODS Construction of a cost-effectiveness model using published data on IFbeta-1b effectiveness and the natural history of RRMS, and new data on costs and quality of life (QoL) from a sample of 102 patients with RRMS and resident in northern England. RESULTS Poorer QoL was found for patients with multiple sclerosis compared with the general population; those who had had a relapse; those with worse states identified by a clinical measure (expanded disability status scale (EDSS)). Relapses have effects over several months. Health state valuations were higher than in the general population. Costs were higher in relapse than remission and for worse EDSS states. IFbeta-1b costs were larger than cost savings. The best cost-effectiveness estimate was pound28 700 per relapse avoided, which is pound809 900 per QALY gained; or pound328 300 per QALY gained allowing for effects of progression over 5 years. Estimates were robust to changes in assumptions. CONCLUSIONS The impact of multiple sclerosis on QoL is substantial. Future trials should base outcomes measurement on QoL and be better linked to natural history and cost data. IFbeta-1b produces important occasional short term QoL gains, but small gains in QALYs overall and large additional costs.