Rates, predictors, and consequences of remission from chronic migraine to episodic migraine

OBJECTIVES: This study has 3 objectives: 1) to estimate remission rates in a population-based sample of subjects with chronic migraine (CM); 2) to identify potential predictors of CM remission; and 3) to assess the influence of CM remission on headache-related disability. METHODS: The American Migraine Prevalence and Prevention study is a prospective, population-based, mailed questionnaire survey, which included questions regarding headache frequency, symptomatology, demographics, comorbidities, health care utilization, and headache-related disability. Three years of longitudinal data were analyzed to determine rates of CM remission and assess predictors of remission using logistical regression models. The consequence of remission was measured by changes in disability, as measured by the Migraine Disability Assessment, over time. RESULTS: A total of 383 respondents had CM in 2005 and follow-up data in 2006 and 2007. Over 2 years, among those with CM at baseline, approximately 34% (n = 130) had persistent CM while 26% (n = 100) had remitted CM. In our final multivariate model, predictors of remission included baseline headache frequency (15-19 vs 25-31 headache days/month; odds ratio OR 0.29; 95% confidence interval CI 0.11 to 0.75) and absence of allodynia (OR 0.45; 95% CI 0.23 to 0.89). Preventive medication use was associated with lower remission rate (OR 0.41; 95% CI 0.23 to 0.75), but this effect lost significance when headache frequency was included. Over 2 years, those with persistent CM demonstrated increased disability while those with remitted CM demonstrated decreased disability. CONCLUSIONS: These findings have clinical practice implications, as it is important to consider that remission rates are variable. However, the benefit of remission goes beyond symptom reduction and may translate to marked decreases in headache-related disability.