Outcomes and predictors of chronic daily headache in adolescents: a 2-year longitudinal study.

OBJECTIVES: To assess the outcomes and predictors of chronic daily headache (CDH) in a community-based cohort of adolescents.

METHODS: We established a field sample of 122 adolescents (32 M/90 F, ages 12 to 14) with CDH in 2000. These adolescents received annual follow-up by neurologists for 2 years via a semistructured telephone interview. CDH was defined as > or =15 headache days/month, average > or =2 h/day for >3 months; subtypes were classified based on the original and appendix criteria of the International Classification of Headache Disorders (2nd ed.; ICHD-2). Poor outcome was defined as persistence of CDH at 2 years.

RESULTS: Follow-up response rates were 92% in 2001 and 84% in 2002. Average monthly headache frequency was 11.0 +/- 9.7 days in 2001 and 7.7 +/- 6.5 days in 2002. CDH persistence rates were 40% in 2001 and 25% in 2002. Medication overuse declined from 20% (baseline) to 6% at 2 years. The prevalence of migraine did not change throughout the follow-up (67 to 60%), whereas that of tension-type headache deceased from 86 to 46% (p < 0.001). Chronic migraine prevalence increased markedly at baseline and became the most common CDH subtype at follow-up when using the ICHD-2 appendix criteria. During follow-up, seven subjects (6%) dropped out of school. Independent predictors for CDH persistence were medication overuse and major depression.

CONCLUSIONS: Most adolescents with chronic daily headache (CDH) continued to have frequent headaches, although the incidence of CDH declined at follow-up. Migraine diagnosis gained prominence as headache frequency decreased. The percentages of chronic migraine in adolescents with CDH increased obviously if the appendix criteria were applied.