Headache classification by history has only limited predictive value for headache episodes treated in controlled trials with OTC analgesics.

We investigated the consistency between the headache diagnosis based on medical history and three treated headache episodes diagnosed based on a diary. In a randomized double-blind study including individuals with either migraine or tension-type headache (TTH) we showed significant superiority of the fixed combination of acetylsalicylic acid + paracetamol + caffeine over the combination without caffeine, the single preparations, and placebo in the treatment of headache. A neurologist performed a classification of the usual headache episodes and each of the three treated ones in a blinded fashion based on a structured questionnaire. This was done for the 1734 patients included in the efficacy analysis who usually treated their episodic TTH or migraine attacks with non-prescription analgesics. The overall percentage of patients with migraine and TTH remained relatively stable. The treated headache episodes were between 75 and 77% migraine, 18–20% were TTH and 5–7% could not be classified. We observed some s...