[Clinical course and natural history in migraine]

Migraine is one of the common diseases, suffering 8.4 million patients in Japan. Recently conditions associated with chronic migraine were considered to be worse than episodic migraine in socio-economic status, health-related quality of life, and headache-related burden. Preventing the chronification, and improving treatment and management, the natural disease course could give us some clues. Several reports suggested that a population prevalence of chronic migraine is about 2% and approximately 2.5% of patients with episodic migraine develop new-onset chronic migraine each year. The risk factors for converting episodic to chronic migraine were demonstrated as follows: age, low education/socioeconomic status, head injury, attack frequency, obesity, medication overuse, stressful life events, caffeine overuse, snoring, other pain syndromes, allodynia, proinflammatory states, prothrombotic states, and specific genes. It was also focused in comobidity with chronic migraine, such as depression, anxiety, chronic pain, asthma, bronchitis, hypertension, and so on. The ratio converting in reverse was reported as a fourth in two years. We should recognize the burden of migraine patients, and improve patients' outcome under reducing risk factors and assessing the effect of treatment on headache progression.