Chronic migraine: classification and comparisons.

OBJECTIVE: The objective of our study was to field test different chronic migraine (CM) criteria and compare CM epidemiological profiles, which include demographic, personal, and lifestyle characteristics, with high-frequency episodic migraine (HFEM) and low-frequency episodic migraine (LFEM). METHODS: Questionnaires were mailed to a random sample of 18,000 18-65-year-olds in demographically diverse regions of Germany. The epidemiological data for the three classifications of CM, LFEM and HFEM were assessed using descriptive statistics, Pearson Chi-square, and analysis of variance tests. RESULTS: Among 9350 respondents, CM_I was the most restrictive (N = 37, 0.4%), followed by CM_II (N = 45, 0.5%) and CM_III (N = 185, 2.0%). CM groups did not differ in distribution by age, gender, body mass index, education or smoking and alcohol consumption. Compared to those with LFEM and HFEM, those with CM (CM_III) had significantly different epidemiological profiles. CONCLUSIONS: CM prevalence varies by case definition. The epidemiological profiles of the three CM groups are similar but differ significantly from those of HFEM and LFEM. Optimal definitions for clinical practice and epidemiological research require additional field testing.

Disability, HRQoL and resource use among chronic and episodic migraineurs: results from the International Burden of Migraine Study (IBMS).

BACKGROUND: Migraine imposes significant burden on patients, their families and health care systems. In this study, we compared episodic to chronic migraine sufferers to determine if migraine status predicted headache-related disability, health-related quality of life (HRQoL) and health care resource utilization. METHODS: A Web-based survey was administered to panelists from nine countries. Participants were classified as having chronic migraine (CM), episodic migraine (EM) or neither using a validated questionnaire. Data collected and then analyzed included sociodemographics, clinical characteristics, Migraine Disability Assessment, Migraine-Specific Quality of Life v2.1, Patient Health Questionnaire and health care resource utilization. FINDINGS: Of the respondents, 5.7% had CM and 94.3% had EM, with CM patients reporting significantly more severe disability, lower HRQoL, higher levels of anxiety and depression and greater health care resource utilization compared to those with EM. INTERPRETATION: These results provide evidence that will enhance our understanding of the factors driving health care costs and will contribute to development of cost-effective health care strategies.

Sociodemographic and comorbidity profiles of chronic migraine and episodic migraine sufferers.

OBJECTIVE: To characterise and compare the sociodemographic profiles and the frequency of common comorbidities for adults with chronic migraine (CM) and episodic migraine (EM) in a large population-based sample. METHODS: The American Migraine Prevalence and Prevention (AMPP) study is a longitudinal, population-based, survey. Data from the 2005 survey were analysed to assess differences in sociodemographic profiles and rates of common comorbidities between two groups of respondents: CM (ICHD-2 defined migraine; > or =15 days of headache per month) and EM (ICHD-2 defined migraine; 0-14 days of headache per month). Categories of comorbid conditions included psychiatric, respiratory, cardiovascular, pain and 'other' such as obesity and diabetes. RESULTS: Of 24 000 headache sufferers surveyed in 2005, 655 respondents had CM, and 11 249 respondents had EM. Compared with EM, respondents with CM had stastically significant lower levels of household income, were less likely to be employed full time and were more likely to be occupationally disabled. Those with CM were approximately twice as likely to have depression, anxiety and chronic pain. Respiratory disorders including asthma, bronchitis and chronic obstructive pulmonary disease, and cardiac risk factors including hypertension, diabetes, high cholesterol and obesity, were also significantly more likely to be reported by those with CM. DISCUSSION: Sociodemographic and comorbidity profiles of the CM population differ from the EM population on multiple dimensions, suggesting that CM and EM differ in important ways other than headache frequency.

Global prevalence of chronic migraine: a systematic review.

The aim of this review was to summarize population-based studies reporting prevalence and/or incidence of chronic migraine (CM) and to explore variation across studies. A systematic literature search was conducted. Relevant data were abstracted and estimates were subdivided based on the criteria used in each study. Sixteen publications representing 12 studies were accepted. None presented data on CM incidence. The prevalence of CM was 0-5.1%, with estimates typically in the range of 1.4-2.2%. Seven studies used Silberstein-Lipton criteria (or equivalent), with prevalence ranging from 0.9% to 5.1%. Three estimates used migraine that occurred ≥15 days per month, with prevalence ranging from 0 to 0.7%. Prevalence varied by World Health Organization region and gender. This review identified population-based studies of CM prevalence, although heterogeneity across studies and lack of data from certain regions leaves an incomplete picture. Future studies on CM would benefit from an International Classification of Headache Disorders consensus diagnosis that is clinically appropriate and operational in epidemiological studies.

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.