Treating medication overuse headache: More than improving headache

Medication overuse and medication overuse headache (MOH) are a major healthcare problem (1,2). In some tertiary headache centres, patients with MOH constitute up to 50% of the patients referred. The study by the COMOEASTAS group is a milestone for our understanding of the condition and the benefit of treatment. The multicentre, multinational prospective study recruited 694 patients with MOH and followed them for 6 months after ‘detoxification’ (3). In this context detoxification is misleading because the term implies that patients with MOH are ‘dependent’ on their medication. This might be true for patients overusing opioids or barbiturates, but not for patients overusing simple analgesics or triptans. Patients with overuse of opioids and or barbiturates were excluded from the present study. We still have no concept on the relationship between frequent intake of, for example, triptans and MOH: does the frequent intake of triptan lead to an increase in migraine frequency or are patients using more triptans because the headache becomes more frequent?

The COMOESTAS study not only investigated the reduction of headache days after ‘detoxification’, but also the reduction in disability and the most important comorbidity of MOH, namely depression and anxiety. The study showed a highly significant and clinically relevant improvement in disability measured with the MIDAS score, and in depression and anxiety measured with the HADS score.

What are the strengths of the paper? The study was multicentre and prospective. The patient number is high, the observation period of 6 months reasonable. Validated instruments such as the MIDAS (3,4) and HADS were used. The study was funded by the EU without involvement from industry.

What are the shortcomings? The study had no control group with follow-up but without intervention. Therefore, we cannot exclude that part of the positive outcome is caused by spontaneous improvement or regression to the mean. Ideally, we would need a properly powered randomized trial. About 200 patients were lost to follow-up. The authors fail to provide information on whether patients with psychiatric comorbidity were treated for their condition. It is conceivable that many patients with depression and/or anxiety were not diagnosed prior to study entry and therefore not treated.

Another problem is that we still do not know how improvement in headache relates to the improvement of psychiatric comorbidity. A multivariate analysis of baseline variables and outcomes would have been helpful.

What are the practical consequences of the study? MOH needs to be identified and treated. My personal approach is to counsel patients with MOH. About one-third of them will be able to reduce the monthly intake of medication to treat acute migraine attacks below the critical threshold. The remaining patients are treated with topiramate or botulinum toxin in addition to behavioural therapy and exercise (5). Patients who fail this approach undergo a formal ‘withdrawal’ regimen in a 1-week day care setting.

An important issue is the difference in MOH in the USA and the rest of the world. In the USA many patients with MOH overuse barbiturates and/or opioids (6,7). The prognosis of this group of patients is different from patients overusing simple analgesics or triptans. Therefore, the results of COMOESTAS do not necessarily apply in the USA.