Migraine is a common illness characterised by severe, often throbbing and/or unilateral headache, which may be accompanied by sensitivity to light or noise. A minority of migraine attacks are preceded by transient visual or sensory disturbances. Migraine is associated with reductions in health-related quality of life, both during and between attacks.
Despite methodological limitations in cost-of-illness studies, it is clear that the cost of migraine to society is substantial. Indirect costs (primarily workplace productivity losses) make up 75 to 90% of total costs. Direct costs, such as the cost of drug treatment, physician consultation, hospitalisation and emergency room treatment, make up most of the remainder.
Sumatriptan is an effective and well tolerated agent in the treatment of migraine. Its main advantage over other agents used in the acute management of migraine appears to be its rapid onset of action. Sumatriptan reduces headache severity within 2 hours of oral administration in 50 to 67% of patients and within 1 hour of subcutaneous administration in 70 to 80% of patients. Headache recurs in approximately 40% of patients who initially respond to oral or subcutaneous sumatriptan; however, a second dose of the drug is effective against the symptoms of recurrence in a majority of patients. Some patients experience relief of non-headache migraine symptoms, including nausea, vomiting, photophobia and phonophobia. Adverse events reported after sumatriptan are generally mild and transient.
Data from studies of patients who used their usual therapies and sumatriptan in nonblinded, sequential phases indicate that both workplace and nonworkplace productivity losses were reduced during sumatriptan therapy. A cost-benefit analysis applied to some of these workplace productivity data indicated that, including direct costs and productivity savings, sumatriptan was associated with a net reduction in total cost of migraine. In retrospective cost analyses, sumatriptan was associated with increased prescription costs; the effect of the drug on other direct treatment costs was less clear. A retrospective pharmacoeconomic model suggested that the cost-effectiveness of subcutaneous sumatriptan versus subcutaneous dihydroergotamine depended on which outcome measure was of greatest interest. For measures of rapid relief of migraine, sumatriptan was superior, but the cost of achieving rapid relief was substantial.
Sumatriptan improved global quality-of-life scores compared with patients’ usual therapy in a randomised crossover trial and appeared to do the same when the drugs were administered in nonblinded, sequential phases in trials which used general and migraine-specific quality-of-life instruments.
Thus, sumatriptan is associated with a fast onset of action and improvements in health-related quality of life in patients with migraine. However, the cost of achieving rapid relief of migraine symptoms may be substantial. Compared with patients’ usual treatments, sumatriptan appeared to reduce workplace and non-workplace productivity losses. However, few economic data from well controlled prospective comparisons of sumatriptan with other available agents are available to quantify the effect of sumatriptan on the overall cost of migraine.
Overview of Migraine
Migraine headache affects 8 to 12% of the general adult population, but is more prevalent in women. Attacks of migraine, which may occur with or without aura, are characterised by severe, often unilateral and/or throbbing, head pain accompanied by nausea and/or sensitivity to light or noise. Transient visual or sensory disturbances (auras) precede a minority of attacks. Migraine is associated with reductions in health-related quality of life, particularly in the dimensions of bodily pain and role-physical (ability to function limited by physical health), both during and between attacks. More than half all of persons with migraine surveyed in the US reported at least 1 severe attack per month. More than 80% of patients report some disability with their attacks. Despite low rates of physician consultation, most persons with migraine use prescription or nonprescription medication for acute migraine headache.
Cost-of-illness estimates are associated with theoretical and methodological limitations; however, it is clear that the cost of migraine to society is substantial. Indirect costs, primarily those resulting from lost workplace productivity, make up the largest portion of total costs (75 to 90%). Estimates of the annual indirect cost of migraine range from $US1.4 to $US17.2 billion in the US (calculated using earnings data published in 1989) and £250 to £741 million in the UK (1990 and 1992 costs, respectively). Estimates of direct costs (e.g. the costs of medication, physician consultation, hospitalisation and emergency room treatment) are about 10 to 25% of the total cost of illness.
Clinical Profile of Sumatriptan
Sumatriptan is an effective and well tolerated agent in the treatment of migraine. Its main advantage over other available antimigraine drugs appears to be its rapid onset of action. Sumatriptan reduces headache severity in 50 to 67% of patients within 2 hours of oral administration and 70 to 80% of patients 1 hour after subcutaneous administration. Headache recurred within 48 hours in approximately 40% of patients who initially responded to the drug. A second dose of medication administered for symptom recurrence was effective in the majority of patients.
In randomised studies, headache relief after oral sumatriptan was as good as, or better than, that provided by other oral agents, including aspirin plus metoclopramide, ergotamine plus caffeine, and lysine acetylsalicylate plus metoclopramide. Subcutaneous sumatriptan provided more rapid relief of headache pain than subcutaneous dihydroergotamine mesylate (DHE), but was not superior 4 and 24 hours after administration. Fewer patients required rescue medication after oral sumatriptan than after aspirin plus metoclopramide or ergotamine plus caffeine.
Adverse events associated with sumatriptan are generally transient and of mild to moderate severity and would not be expected to substantially increase the cost of migraine treatment. After sumatriptan, some patients experience relief of non-headache migrainous symptoms, including nausea, vomiting, photophobia and phonophobia.
Pharmacoeconomic and Quality-of-Life Considerations
Limitations of available pharmacoeconomic analyses of sumatriptan include the absence of blinding and parallel control groups in most studies. Compared with patients’ usual treatments, oral and subcutaneous sumatriptan are associated with reductions in workplace productivity losses: estimated productivity gains with sumatriptan ranged from 12.1 to 89.8 hours per patient per year. Although of less measurable economic impact, nonworkplace productivity gains — generally less than an hour per treated migraine day — have also been documented with sumatriptan therapy.
A cost-benefit analysis of sumatriptan therapy suggested that the cost of oral sumatriptan 50mg (£220 per patient per year) was more than offset by reductions in workplace productivity losses, resulting in a net annual economic benefit of sumatriptan therapy to society of £125 per patient (1996 costs). In retrospective cost analyses, the introduction of sumatriptan was associated with increased prescription costs, but its effect on other direct costs associated with migraine treatment was unclear.
A pharmacoeconomic model applied retrospectively to a comparison of subcutaneous sumatriptan with subcutaneous DHE suggested that cost effectiveness of the 2 therapies was dependent upon which outcome measure was of greatest interest. For 4 outcome measures associated with rapid relief of migraine symptoms (requirement for no more than 1 dose of medication, ability to carry on as normal 1 hour after first dose and complete relief of symptoms or nausea 1 hour after first dose), the extra cost per patient successfully treated with sumatriptan ranged from $US4131 to $US6697 (1993 dollars). For other measures, DHE was both more efficacious and less expensive; therefore, cost-effectiveness ratios were not calculated. The additional cost of treating 100 patients with sumatriptan instead of DHE was estimated at $US88 395 per year (i.e. $US 884 per patient per year) [1993 dollars].
Health-related quality of life in patients with migraine is improved during treatment with sumatriptan, as demonstrated in a randomised crossover trial. Improvements in global health-related quality-of-life scores and scores for the domains of functional, physical and social impairments and iatrogenic disturbance were significantly greater during sumatriptan therapy than when patients used their usual medications. Health-related quality of life, measured by general and migraine-specific quality-of-life instruments, improved after sumatriptan therapy compared with baseline or scores after patients’ usual therapies, but the lack of parallel control groups and blinding in these studies limits the conclusions that can be drawn.