Identification of the distinctive clinical characteristics of medication overuse headache (MOH) subtypes offers a clearer definition of headache disorder, according to study results published in Headache.

The phenotypic characteristics of MOH vary between patients based on the type of primary headache and on the class of medication being overused. Until now, few studies have compared the clinical features of different MOH subtypes. The objective of this study was to investigate whether different MOH subtypes are associated with specific demographics or phenotypic characteristics in a large population.

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In this descriptive, cross-sectional, observational study, which was part of the COMOESTAS (continuous monitoring of medication overuse headache in Europe and Latin America) project, researchers evaluated data from 660 patients who were enrolled in 6 national headache centers in European and Latin American cities. At the baseline visit, researchers collected clinical characteristics through patient interviews and self-administered questionnaires that measured migraine-related disability, anxiety, and depression. Researchers also conducted post hoc analyses of data collected during the COMOESTAS project to evaluate the efficacy of an ad hoc electric diary on the detoxification outcome in patients with MOH.

Results revealed that patients with simple analgesic headache (A-MOH) were significantly younger (38.3±11.9) than patients with triptans headache (T-MOH) (42.9±11.8; P =.026) and had a shorter duration of episodic headache (13.1±10.9) than those with T-MOH (19.2±11.9; P <.001) and ergotamine headache (E-MOH) (17.8±11.7; P =.017).

Patients with E-MOH had a significantly lower Migraine Disability Assessment score (33.6±41.6) than all other groups, while patients with A-MOH had the highest Migraine Disability Assessment score of all groups (67.8±57.2). Rates of anxiety and depression were lowest in patients with T-MOH (32±30.8 and 31±29.8, respectively; P <.001 and P =.027, respectively). 

There were several limitations to this study — the main limitations being the retrospective collection of data on the clinical history of MOH and limited generalizability of findings to patients with severe or comorbid MOH. Further, the tool used to assess anxiety and depression did not allow in-depth evaluation of patients’ psychological state. Patient recruitment was from headache centers, therefore, findings may not represent the mean population of all patients with MOH. Differences in characteristics of MOH subtypes may also have been influenced by sociocultural characteristics and different patterns in practice and referral method. Finally, the post hoc analysis method used in this study may not be fully replicable for future studies.

The study researchers concluded that the clinical characteristics of MOH subtypes identified by the study provide a clearer definition of headache disorder and offer insights into the possible causes of disabling chronic headache.

Reference

Viana M, De Icco R, Allena M, et al. Clinical subtypes of medication overuse headache – findings from a large cohortHeadache. 2019;59(9):1481-1491.