Chronic migraine in the population
Burden, diagnosis, and satisfaction with treatment
Citation Manager Formats
Make Comment
See Comments

Abstract
Objective: To evaluate the disability profile and patterns of treatment and health care use for chronic migraine (CM) in the general population, in contrast to episodic migraine.
Methods: We identified 24,000 headache sufferers, drawn from more than 165,000 individuals representative of the US population. This sample has been followed up with annual surveys using validated questionnaires for the diagnosis of episodic migraine and CM. As a part of the survey, subjects were asked to report the specific medications currently used for their most severe headaches, as well as level of satisfaction with treatment.
Results: Our sample consisted of 520 individuals with CM and 9,424 with episodic migraine. Over a 3-month period, more than half of the individuals with CM missed at least 5 days of household work, compared with 24.3% of those with episodic migraine (p < 0.001). Reduced productivity in household work for at least 5 days over 3 months was reported by 58.1% and 18.2% (p < 0.001); at least 5 days of missed family activities was reported by 36.9% and 9.5% (p < 0.001). The majority of the CM sufferers (87.6%) had previously sought care to discuss their headaches with a health professional. Migraine-specific acute treatments were used by 31.6% of respondents with CM and 24.8% with episodic migraine. Around 48% of the individuals with CM were satisfied with their acute therapies. Just 33.3% of those with CM were currently using preventive medications.
Conclusion: Chronic migraine (CM) is more disabling than episodic migraine in the population. Although most individuals with CM sought medical care for this disorder, the majority did not receive specific acute or preventive medications.
Glossary
- AMPP=
- American Migraine Prevalence and Prevention;
- CM=
- chronic migraine;
- CM-R=
- chronic migraine, revised definition;
- ICHD-2=
- International Classification of Headache Disorders, Second Edition;
- MIDAS=
- Migraine Disability Assessment;
- NSAID=
- nonsteroidal anti-inflammatory drug;
- OR=
- odds ratio;
- TM=
- transformed migraine.
The second edition of the International Classification of Headache Disorders (ICHD-2) includes six major categories of migraine.1 In addition to migraine with and without aura, the ICHD-2 includes as a complication of migraine a condition termed chronic migraine (CM). This long-recognized2–4 but only recently codified disorder arises in a subgroup of migraine sufferers whose attacks increase in frequency over time.
Originally termed transformed migraine (TM), in the past the condition was defined by 15 or more headache days per month with one of several links to migraine.2 The ICHD-2 initially proposed a restrictive definition of CM.1 Recently revised, the new definition (CM-R) requires 15 or more headache days per month over the past 3 months, with at least 8 headache days per month that meet criteria for migraine without aura or that respond to migraine-specific treatment.5 Clinic-based diary studies show that most patients who meet the older definition of TM also meet the CM-R definition.6,7 Most clinic and population-based studies have used the older TM definition.8,9 Because of the substantial overlap between the revised definition of CM-R and TM, we will use the term CM herein.
Population studies have shown that CM has a prevalence of approximately 2%.10,11 Clinic-based studies suggest that it is even more disabling than migraine.12–14 Because CM is a relatively rare disorder, population burden, as well as patterns of consultation, diagnosis, and treatment, have not been well characterized. Herein, we use data from the American Migraine Prevalence and Prevention (AMPP) study to evaluate the disability profile and patterns of treatment and health care use for CM in the general population. We contrast CM with episodic migraine sufferers drawn from the same population.
METHODS
Study population.
The AMPP study is a longitudinal study following a cohort of headache sufferers selected from a representative sample of the general population.15–18 One of the main objectives of the project is to establish the natural history and prognosis of migraine, as well as risk factors for CM.
The AMPP study is composed of two major phases. In phase 1, we used validated self-administered questionnaires to identify a nationwide sample of headache sufferers. The screening questionnaire was mailed in 2004 to a stratified random sample of 120,000 US households drawn from a 600,000-household national panel maintained by the National Family Opinion, Inc. Of 162,576 individual respondents, 30,721 reported at least one severe headache in the past year.15,16
In phase 2, a random sample of 24,000 headache sufferers was enrolled in a 5-year follow-up study.17,18 Herein we report the most recent data, collected in 2006. Diagnoses were assigned on the 2006 follow-up. Accordingly, if someone had episodic migraine in 2005 and chronic migraine in 2006, a CM diagnosis was assigned. Episodic headache sufferers (<15 days of headache per month) were classified according to the ICHD-2 as having migraine, probable migraine, or tension-type headaches (see below). Individuals with chronic daily headaches (>15 days of headache per month) were subdivided into CM and other chronic daily headaches. In addition, as discussed below, detailed questions on medication use were included.
Description of the survey.
The self administered phase 2 questionnaire comprised 82 questions, assessing headache diagnosis, comorbidities, headache-related impact, health-related quality of life, demographics, and other information of interest (e.g., obesity, cutaneous allodynia). The headache module consists of 21 questions for each of up to three headache types. The survey had been previously shown to have a sensitivity of 100% and specificity of 82.3% for the diagnosis of migraine.19 The questionnaire has a sensitivity of 93% and a specificity of 85% to the diagnosis of CM.7
Disability.
Disability was assessed with the Migraine Disability Assessment (MIDAS) questionnaire. MIDAS captures information on missed days of work, household chores, and nonwork activity and days with substantially reduced productivity (i.e., more than 50% reduction in productivity) in the same domains over a 3-month period.20 A total score is calculated by adding the five headache-related disability items together. Higher scores indicate increased disability due to headache. Scores can also be classified into four severity grades: little or none (0–5), mild (6–10), moderate (11–20), and severe (≥21). MIDAS has been shown to be valid, responsive, and reliable in a population-based sample conducted in the United States and the United Kingdom. MIDAS scores have also been shown to be unrelated to sex or work status.21
Assessment of treatment.
As a part of the survey, subjects were asked a series of questions regarding acute and preventive treatment. Individuals who experienced multiple headache types were asked to report the types of treatment currently used for their most severe headache pain, the specific medications currently used to treat their headaches, and the number of days per month they used the medications. First, we probed acute medications currently used for the treatment of headache, with a list of medications divided by class, containing their generic and brand names. Subjects were asked to report the types of treatment currently used for their most severe headache pain, the specific medications currently used to treat their headaches, and the number of days per month they used the medications. We specifically asked about all triptans in the several formulations, ergotamine compounds, seven nonsteroidal anti-inflammatory drugs (NSAIDs), nine over-the-counter medications, eight opioids, two butalbital-containing compounds, and medications containing isometheptene. For preventive medications, we first asked whether individuals were using prescribed or nonprescribed daily medications for the treatment of headaches. A list presented the name of medications commonly used for migraine, including antiepileptic drugs, antidepressants, antihypertensive drugs, nutraceuticals (feverfew, butterbur, vitamins and minerals, etc.), and other drugs.
Satisfaction with treatment.
Satisfaction was assessed using direct statements (e.g., “After taking my medication I am satisfied with the complete relief of pain in 2 hours,” or “My medication decreased the number of headache days by at least 50%”). Some questions were answered on a five-point scale (strongly agree, agree, neutral, disagree, and strongly disagree). Other questions were answered on a four-point scale (50% or more of the time, less than 50% of the time, rarely, and never).
Data analysis.
Data were summarized using frequency counts, descriptive statistics, summary tables, and graphics.
The impact of CM on daily activities, as well as the patterns of diagnosis, was contrasted with episodic migraine. We created tables of contingencies and used the χ2 test for sequential categories to contrast proportions. A p value < 0.05 was considered significant.
The study has been approved by the Albert Einstein College of Medicine Investigation Review Board.
RESULTS
Description of the sample.
Of 24,000 headache sufferers surveyed in 2005, 16,573 returned complete questionnaires (69.0% response rate). Just responders in 2005 were resurveyed in the 2006 follow-up, and 14,540 returned the questionnaires (87.7% response rate). A total of 9,494 had migraine, and 520 had CM (table e-1 on the Neurology® Web site at www.neurology.org). To assess for participation bias, we contrasted the demographics of the target sample, and of responders in the baseline (2005) and follow-up (2006) surveys. The demographics of the 2006 sample were similar to the demographics of the 2005 respondents and of the target sample. Responders did not differ from nonresponders on region of the country, state, race, sex of the head of household, annual household income, or household size. Responders differed from nonresponders on age (odds ratio [OR] = 0.76, 95% CI = 0.72–0.78) and sex (male vs female, OR = 0.72, 95% CI = 0.67–0.76). Responders did not differ from nonresponders as a function of headache diagnosis (migraine vs not), headache frequency, or severity. Responders and nonresponders did not significantly different as a function of type of acute medication used in 2005.
Impact of chronic migraine.
The impact of CM as assessed by the MIDAS questionnaire, was significantly greater than the impact of episodic migraine (table 1). Over a 3-month period, 8.2% of the CM sufferers and 2.2% of the episodic migraineurs missed at least 5 days of work and school (p = 0.001). At least 5 days of significant reduction in productivity were reported by 33.8% and 12.3% (p < 0.001). More than half of the individuals with CM missed at least 5 days of household work, compared with 24.3% of the migraineurs (p < 0.001). Reduced productivity in household work for at least 5 days over 3 months was reported by 58.1% and 18.2% (p < 0.001); at least 5 days of missed family activities was reported by 36.9% and 9.5% (p < 0.001).
Table 1 Impact of chronic migraine on daily activities over a 3-month period: Comparison with episodic migraine
Diagnosis and health care.
The vast majority of the CM sufferers (87.6%) had previously sought care to discuss their headaches with a health professional. Most (73.6%) had at least one consultation over the past year. The figure lists the professionals ever consulted for headache purposes. The majority of those who had consulted did so with a family practice doctor (80.1%), followed by a neurologist (41.6%). Chiropractors were sought by 36.2%. Headache or pain doctors were seen by 26.9%. Nonetheless, just 20.2% of those with CM received a diagnosis of CM, chronic daily headache, or transformed migraine. Another 13.9% were told that they had rebound headaches or medication overuse headaches. Data for episodic migraine are also presented for reference.
Figure Health care providers ever sought for headache by individuals with chronic migraine (CM) and migraine
Patterns of and satisfaction with acute treatment for CM.
Migraine-specific acute treatments were used by 31.6% of respondents with CM and 24.8% with episodic migraine. For CM, more than 97% of migraine-specific prescriptions were triptans, mostly oral (83.0%). Sumatriptan (49.7%), zolmitriptan (13.4%), and rizatriptan (11.4%) were the most commonly prescribed triptans. Opioids were frequently used (28.6% of individuals, mean of 14.4 days per month). Butalbital-containing compounds were used by 15.1% of the sample (mean of 15.6 days per month), and compounds containing isometheptene were used by 3.9% (table e-2).
One or more over-the-counter medications were used by 82.6% of respondents with CM (mean of 15.9 days per month). NSAIDs were used by 63.1% of the sample, with ibuprofen (45.2% of NSAID use), naproxen (26.2%), and aspirin (23.6%) being the most common. CM sufferers used NSAIDs an average of 14.8 days per month. Acetaminophen (45.3%) and acetaminophen with caffeine (38.1%) were also commonly used. Around 48% of the individuals with CM were satisfied with their acute therapies, 23% were dissatisfied, and the remaining were neutral (table 2). Less than one-third considered that the medications reduced in 50% or more the impact of their attacks, but most (60.1%) agreed that the medications were well tolerated. More than 43% were consistently able to quickly return to their daily activities after using their usual acute medication, but just 35% reported being pain free at 2 hours on at least 50% of the attacks. Less than one-third reported meaningful relief over 24 hours on most attacks, although nearly 80% considered their medication tolerable.
Table 2 Satisfaction with acute therapies by individuals with chronic migraine in the US population, in 2006
Patterns of and satisfaction with preventive treatment for CM.
Medications specifically taken to prevent headaches had ever been used by a minority of the individuals with CM (40.0%). Just 33.3% were currently using preventive medications for CM.
Table 3 displays the medications ever used by individuals with CM for specifically preventing their headaches. For reference, we also present the medications ever used by episodic migraineurs. Among the antiepileptic drugs, topiramate had ever been used by 32.7%, whereas gabapentin and divalproex each had been used by around 20% of the individuals. Among the antidepressant medications, amitriptyline had been used by 32.7%, whereas nortriptyline was ever used by 9.1%. A large proportion of CM suffers had ever used a selective serotonin reuptake inhibitor as a headache preventive.
Table 3 Preventive therapies ever used by individuals with chronic migraine in the US population, in 2006
Among the antihypertensive medications, propranolol had ever been used by 21.6%, whereas metoprolol was used by 7.2% and verapamil was used by 9.2%.
Nutraceuticals were frequently reported as ever being used. Magnesium (10.6%), feverfew (10.1%), and riboflavin (9.6%) were the most commonly used.
The satisfaction with preventive treatments is displayed in table 4. Because we did not account for the order of treatment or for the presence of comorbidities (e.g., it may be that antiepileptic drugs are used frequently in patients who did not respond to a first class of treatment or that antidepressants are preferentially used in individuals with depression), we elected not to conduct formal comparisons among drugs. Among the antidepressants, more than 70% of the patients using amitriptyline were satisfied with the drug, compared with 51% for nortriptyline. For selective serotonin reuptake inhibitors, rates ranged from 48% for sertraline and 62% with duloxetine. More than 60% of the patients using amitriptyline considered that it was associated with significant reduction in headache frequency, and 65% considered it well tolerated.
Table 4 Satisfaction with preventive medications by individuals with chronic migraine in the US population, in 2006
More than three quarters of the CM sufferers were satisfied with propranolol, whereas 66% were satisfied with verapamil. Nearly 70% of the subjects receiving propranolol had important reduction in headache frequency; it was well tolerated by 80% of them.
Among the antiepileptic drugs, 66% of patients receiving topiramate considered that the medication was associated with at least 50% in headache frequency (66%). Both topiramate and divalproex had numerically similar effects on disability. More than 70% of patients currently using topiramate considered it to have few side effects, vs 61% using divalproex and 56% using gabapentin.
Nutraceuticals were associated with satisfaction levels ranging from 40% (magnesium) to 58% (feverfew). They were well tolerated.
DISCUSSION
This study provides of data on the burden of CM in the general population. In the present study, we found that CM is a disabling form of primary headache, even more disabling then episodic migraine. It is often said that in the process of migraine transformation, as attacks increase in frequency, the severity of attacks decrease.2,3,22,23 The present data clearly indicate that within the same population sample, CM results in more disability per person than episodic migraine. That is, the increasing frequency of headache more than offsets any decrease in the average impact of each attack.
The majority of individuals with CM have consulted a doctor at least once for their headaches. Consultation rates are higher than for migraine.15,16 Consultation behavior in CM has rarely been reported in population studies. Diagnostic rates for CM were surprisingly low. Only a minority report that they were told that they had transformed migraine, CM, chronic daily headaches, or medication overuse headaches. Most CM sufferers seek care in the primary care setting.
The contrasts between CM and episodic migraine are of interest. For episodic migraine, a number of factors contributing to underdiagnosis have been identified.2,24,25 Migraineurs may not seek medical care for migraine, they may seek care but not have received a diagnosis, or they may have been given a diagnosis but do not remember or report it.26 Lack of consultation for episodic headache is a major contributing factor to underdiagnosis.26–28 For CM, lack of consultation does not explain the lack of diagnosis. A more important determinant is probably the lack of medical comfort with the diagnosis of chronic daily headache and its subtypes.
Most CM sufferers treat their headache exacerbations with nonspecific migraine medications. Although most consider their medications well tolerated, a sizable proportion are dissatisfied with their acute medicines. Future analyses should focus on the comparison of satisfaction after specific vs nonspecific acute migraine medications, after adjusting for disability and severity of pain. Furthermore, evidence suggests that in individuals with CM, preventive treatment improves the efficacy of rescue medication,29,30 a potential area for future analyses.
Although virtually everyone with CM should receive preventive medications, just one-third use it. According to Headache Consortium Guidelines, prescription preventive medication is warranted for migraineurs with frequent or disabling attacks.31–33 Satisfaction with preventive medication, among individuals current taking it, was high. With first-line preventive medications, it ranged from 51% with nortriptyline to around 75% with topiramate and propranolol. These rates should not be taken as satisfaction overall, because patients who were dissatisfied with their preventive medications are likely to discontinue it or to switch it to another. Nonetheless, most individuals current taking preventive medication are fairly satisfied with their medicines. From a health care perspective, better identification of individuals with CM, and adequate prescription of specific acute and preventive medications, should be a priority.
This study has limitations. First, the validated questionnaire was applied in just those with a self-defined severe headache. Because migraine and CM attacks do not have to be severe,1 we may have missed individuals with less severe forms of CM. However, we have demonstrated that our questionnaires have good sensitivity and specificity in the population. Second, headache sufferers with lower disability may be less likely to participate in the interview. Third, information on medication use was self-reported. Finally, in the AMPP study, in phase 1, we interviewed a representative US sample of individuals with or without headache to assess the prevalence of episodic migraine (11.8%) and chronic daily headaches, including CM (4%). In phase 2, we established a cohort of headache sufferers, focusing on episodic migraine. One reason we did that is to enhance our power to assess transformation from episodic into chronic migraine. Therefore, the 520 individuals with CM do not reflect its population prevalence, and the proportion of CM/episodic migraine is not representative of what is seen in the population, where expected rates vary from 1:4 to 1:6. Strengths of this study include the robust sample size and the meticulous collection of information on medications, including over-the-counter medications.
CM is a disabling, underdiagnosed, unrecognized, and undertreated disorder. Public health strategies should focus on educating health providers about the fact that CM is a migraine subtype1 worthy of diagnosis and treatment. Clinical trials that assess the effectiveness of current and in-development medications for the treatment of CM are urgently needed to provide patients and doctors with evidence-supported treatment options.
Footnotes
-
Supplemental data at www.neurology.org
Disclosure: This study was sponsored by the National Headache Foundation through grants from Ortho-McNeil Neurologics, Inc., and Allergan Inc. M.E.B. started employment at Merck on December 31, 2007. M.E.B. and R.B.L. received grant support, were in advisory boards over the past 12 months, or were on the speakers’ bureau of Merck, AstraZeneca, Pfizer, GlaxoSmithKline, Allergan, Endo, and Ortho-McNeil Pharmaceutical, among other companies. D.S. and M.R. received research support from Ortho-McNeil Pharmaceutical and Allergan.
Received January 11, 2008. Accepted in final form May 6, 2008.
REFERENCES
- 1.↵
Headache Classification Committee of the International Headache Society. Classification and diagnostic criteria for headache disorders, cranial neuralgias, and facial pain: second edition. Cephalalgia 2004;Suppl 1:1–160.
- 2.↵
Silberstein SD, Lipton RB, Sliwinski M. Classification of daily and near-daily headaches: field trial of revised IHS criteria. Neurology 1996;47:871–875.
- 3.
- 4.
- 5.↵
Headache Classification Committee of the International Headache Society. New appendix criteria open for a broader concept of chronic migraine. Cephalalgia 2006;26:742–746.
- 6.↵
Bigal ME, Tepper SJ, Sheftell FD, Rapoport AM, Lipton RB. Field testing alternative criteria for chronic migraine. Cephalalgia 2006;26:477–482.
- 7.↵
Liebestein M, Bigal ME, Sheftell FD, Rapoport AM, Tepper S, Lipton RB. Validation of the chronic daily headache questionnaire. Neurology 2007;68:369.
- 8.↵
Bigal ME, Rapoport AM, Sheftell FD, Tepper SJ, Lipton RB. Transformed migraine and medication overuse in a tertiary headache centre: clinical characteristics and treatment outcomes. Cephalalgia 2004;24:483–490.
- 9.
Mathew NT. Transformed migraine. Cephalalgia 1993;13 (suppl 12):78–83.
- 10.↵
- 11.
- 12.↵
- 13.
- 14.
- 15.↵
Lipton RB, Bigal ME, Diamond M, et al. Migraine prevalence, disease burden, and the need for preventive therapy. Neurology 2007;68:343–349.
- 16.
- 17.↵
- 18.
- 19.↵
- 20.↵
- 21.↵
Stewart WF, Lipton RB, Simon D. Work-related disability: results from the American Migraine study. Cephalalgia 1996;16:231–238.
- 22.
Bussone G, Grazzi L, Usai S, et al. Disability in migraine patients: Italian experience. J Headache Pain 2001;2 (suppl):2361–2369.
- 23.
- 24.
- 25.
- 26.↵
- 27.
Lucas C, Chaffaut C, Artaz MA, Lanteri-Minet M. FRAMIG 2000: medical and therapeutic management of migraine in France. Cephalalgia 2005;25:267–729.
- 28.
- 29.↵
- 30.
Andrade J, Maciel-Júnior JA, Cladellas XC, Correa-Filho HR, Machado HC. Acupuncture in migraine prophylaxis: a randomized sham-controlled trial. Cephalalgia 2006;26:520–529.
- 31.↵
Matchar DB, Young WB, Rosenerg J, et al. Multispecialty consensus on diagnosis and treatment of headache: pharmacological management of acute attacks. Available at: www.aan.com/public/practiceguidelines/03.pdf. Accessed January 4, 2008.
- 32.
Pryse-Phillips WE, Dodick DW, Edmeads JG, et al. Guidelines for the diagnosis and management of migraine in clinical practice. Canadian Headache Society. CMAJ 1997;156:1273–1287.
- 33.
Disputes & Debates: Rapid online correspondence
REQUIREMENTS
If you are uploading a letter concerning an article:
You must have updated your disclosures within six months: http://submit.neurology.org
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.