Beta-interferon may be a cost-effective treatment for multiple sclerosis if it is used long-term, as current estimates of its overall cost are based on an incorrect assumption, according to two health economists.
Mr Ian Johnson and Mr Malcolm Kendrick (Interphase, Macclesfield) say that current analyses of the costs of using beta-interferon are based on the assumption that any beneficial effect on disease progression ceases the moment that drug treatment is stopped.
They argue that any treatment that slows the process of central nervous system degeneration will delay progression of the disease for many years and, if treatment is given long-term, disease progression is delayed even after beta-interferon is stopped.
Commenting on their analysis, the authors say: "Over two to three years, the impact of treatment on patients' quality of life is relatively small and cost-utility analyses that do not consider longer term benefits nor include societal costs may be misleading."
Economic analysis based on this assumption gives cost per quality-adjusted life year values for beta-interferon treatment of between £27,000 to £38,000, rather than the £1m given by previous analyses, they say. They found that, initially, the annual cost of care exceeded that of standard care (ie, management without beta-interferon); by year seven, the cost of standard care equalled that of treatment using beta-interferon and, by year 12, the cumulative costs had converged. Cost savings could be made thereafter, they add.
This was because of greater disability in the standard care group compared with the beta-interferon group, which gave rise to increased costs to both the NHS and society.
The study was funded by a grant from Biogen, the manufacturer of Avonex (interferon beta-1a) and is published in Pharmacoeconomics (2000;18:45).