Cost-effectiveness analysis of stratified versus stepped care strategies for acute treatment of migraine: The Disability in Strategies for Care (DISC) Study.
BACKGROUND
The Disability in Strategies for Care (DISC) study was the first large randomised controlled trial to compare alternative treatment strategies in the acute treatment of migraine. With 835 patients in its intention-to-treat efficacy analysis, DISC compared a stratified care strategy, where initial therapy was based on clinical need as determined by the Migraine Disability Assessment Scale (MIDAS) and two stepped care strategies (across attacks and within attacks), where first-line therapy with a simple combination analgesic was escalated, if response had been inadequate, to zolmitriptan, a migraine-specific therapy.


OBJECTIVE
To report on the cost effectiveness of these three strategies from a societal perspective.


STUDY DESIGN AND METHODS
A cost-effectiveness analysis was undertaken using data from the DISC study, and including both health service and productivity costs. Data were collected prospectively on drug usage (main therapy and rescue medication); resource use associated with adverse events was estimated by a clinician blinded to treatment strategy. Health service resource use was costed using UK unit costs (1999 to 2000 values). Data were collected using diary cards on the amount of time patients lost from work, and on reduced effectiveness at work, due to a migraine attack. This facilitated an estimate of the productivity costs associated with the treatment strategies. To assess cost effectiveness, the differences in costs between the strategies were related to the two primary outcome measures in the trial: headache response 2 hours after initial therapy and disability-adjusted time during the first 4 hours after initial therapy.


RESULTS
Although the mean health service cost was higher in the stratified care group (mean over 6 attacks of pound 28.25 versus pound 11.74 and pound 23.15 in the stepped care across attacks group and within attacks group, respectively), mean productivity costs over 6 attacks were lower in the stratified group (pound 112.22 versus pound 144.70 and pound 127.53). The total mean cost over six attacks was, therefore, lowest in the stratified care group (pound 138.95 compared with pound 157.19 in the stepped care across attacks group and pound 148.53 in the stepped care within attacks group), although these differences did not reach statistical significance. In terms of headache response, stratified care was statistically significantly more effective than both forms of stepped care. Using disability-adjusted time, stratified care was statistically significantly more effective than stepped care across attacks, but not against stepped care within attacks.


CONCLUSION
Given its lower mean costs and higher mean effectiveness, a stratified care strategy, which included zolmitriptan, was the dominant strategy and was unequivocally more cost effective from a societal perspective than either stepped care strategy. When the uncertainty around these means was considered, stratified care had the highest probability of being cost effective.