Medication-overuse headache in China: clinical profile, and an evaluation of the ICHD-3 beta diagnostic criteria.

Background: Although medication-overuse headache (MOH) is common in China, its clinical profile is not yet fully established. Meanwhile, ICHD-3 beta has been published, but its diagnostic criteria require further validation.

Methods: We retrospectively classified the clinical features of 240 consecutive patients with MOH (55 males, 185 females), whose demographic data, headache features, overused medications (type, quantity, frequency and duration of use), headache-attributed burden, and outcomes were reviewed. We then applied the criteria of the several versions of ICHD (II, IIR and 3-beta) to these patients.

Results: Compared with those with other headaches, patients with MOH were more likely to be less well educated (64.6% vs 42.0% for secondary school or lower, p < 0.0001), and on lower annual incomes (72.3% vs 56.0% for an income of Chinese yuan (CNY) 30,000 or less, p < 0.0001). Combination analgesics were the most commonly overused medications, and, caffeine (89.9%), aminopyrine (70.0%), phenacetin (53.9%) and phenobarbital (48.8%) were the most commonly used specific components of these. Only two patients (0.8%) had previously been given the diagnosis of MOH; accordingly, the median time to diagnosis after the estimated onset of the disorder was 4.0 years. The majority of patients (83.7%) improved with treatment. All 240 patients fulfilled the diagnostic criteria for MOH according to ICHD-3 beta; only 134 (55.8%) satisfied the diagnostic criteria for definite MOH according to ICHD-II, while 195 (81.2%) met those of ICHD-IIR.

Conclusions: MOH in China is associated with lower educational level and annual income. MOH has rarely been diagnosed and correctly treated in China. ICHD-3 beta appears to be more appropriate for the diagnosis of MOH than previous versions.