Prevalence, natural history and dynamic nature of chronic headache and medication overuse headache in Italy: The SPARTACUS study.

Background: Chronic headaches and medication overuse headache are common and burdening conditions. No studies have evaluated the prevalence of chronic headache and medication overuse headache in an unselected Italian population.

Methods: We performed a three-year cross-sectional and longitudinal population-based study to investigate prevalence, natural history, and prognostic factors of chronic headache. We delivered a self-administered questionnaire to 25,163 subjects. Chronic headache patients were interviewed by General Practitioners. After three years, medication overuse headache patients were invited to undergo a neurological evaluation at our Center.

Results: 16,577 individuals completed the questionnaire; 6878 (41,5%) were episodic headache sufferers and 636 (3.8%) were chronic headache subjects. 239 (1.4%) patients were acute medication over-users. All medication overuse headache patients had migraine or headache with migrainous features. At the three-year follow-up of 98 patients, we observed conversion to episodic headaches in 53 (54.1%) patients. 27 (50.9%) patients remitted spontaneously.

Conclusions: We present the first prevalence data on chronic headache and medication overuse headache in an unselected Italian population and a high rate of spontaneous remission. These data support the interpretation of medication overuse headache as a specific migraine-related disorder that may reflect chronic migraine's dynamic nature, the need for more specific medication overuse headache diagnostic criteria, and highlight the priority of targeted public health policies.