Is chronic migraine one end of a spectrum of migraine or a separate entity?

Chronic migraine is associated with abnormalities in the periaqueductal grey that may be progressive. The condition is also associated with a greater degree of impairment in cortical processing of sensory stimuli than episodic migraine, perhaps due to more pervasive or persistent cortical hyperexcitability. These findings fit with the model of migraine as a spectrum disorder, in which the clinical and pathophysiological features may progress over time. This progression may result from changes in nociceptive thresholds and ensuing central sensitization caused by recurrent migraine in susceptible individuals. This may lead to changes in baseline neurological function between headaches, evident not only in electrophysiological and functional imaging studies, but also as psychological and somatic complaints that occur after years of episodic migraine. From current research and migraine models, a conceptualization of chronic migraine is emerging in which relatively permanent and pervasive central changes have occurred that warrant novel and tolerable treatments.     

Mechanism of Chronic Migraine

Chronic migraine typically evolves from episodic migraine over months to years in susceptible individuals. Headaches increase in frequency over time, becoming less intense but more disabling and less responsive to treatment. Results of electrophysiologic and functional imaging studies indicate that chronic migraine is associated with abnormalities in the brainstem that may be progressive. Additionally, chronic migraine is associated with a greater degree of impairment in cortical processing of sensory stimuli than is episodic migraine, perhaps due to a more pervasive or persistent cortical hyperexcitability. These findings fit with the model of migraine as a spectrum disorder, in which the clinical and pathophysiological features of migraine may progress over time. This progression is postulated to result from changes in nociceptive thresholds and ensuing central sensitization caused by recurrent migraine in susceptible individuals, for whom a variety of risk factors have been described. This may lead to changes in baseline neurologic function between episodes of headache, evident not only in electrophysiologic and functional imaging studies, but also as an increase in depression, anxiety, nonhead pain, fatigue, gastrointestinal disorders, and other somatic complaints that may occur after years of episodic migraine. From the current research and migraine models, a conceptualization of chronic migraine, in which relatively permanent and pervasive central changes that warrant novel and tolerable treatments have occurred, is emerging. This model also implies that prevention of chronic migraine is an important goal in the management of episodic migraine, particularly in individuals who exhibit risk factors for chronic transformation.     

Panic Disorder and Migraine: Comorbidity,Mechanisms, and Clinical Implications

A growing body of literature suggests that comorbid anxiety disorders are more common and more prognostically relevant among migraine sufferers than comorbid depression. Panic disorder (PD) appears to be more strongly associated with migraine than most other anxiety disorders. PD and migraine are both chronic diseases with episodic manifestations, involving significant functional impairment and shared symptoms during attacks, interictal anxiety concerning future attacks, and an absence of identifiable secondary pathology. A meta‐analysis of high‐quality epidemiologic study data from 1990 to 2012 indicates that the odds of PD are 3.76 times greater among individuals with migraine than those without. This association remains significant even after controlling for demographic variables and comorbid depression. Other less‐rigorous community and clinical studies confirm these findings. The highest rates of PD are found among migraine with aura patients and those presenting to specialty clinics. Presence of PD is associated with greater negative impact of migraine, including more frequent attacks, increased disability, and risk for chronification and medication overuse. The mechanisms underlying this common comorbidity are poorly understood, but both pathophysiological (eg, serotonergic dysfunction, hormonal influences, dysregulation of the hypothalamic–pituitary–adrenal axis) and psychological (eg, interoceptive conditioning, fear of pain, anxiety sensitivity, avoidance behavior) factors are implicated. Means of assessing comorbid PD among treatment‐seeking migraineurs are reviewed, including verbal screening for core PD symptoms, ruling out medical conditions with panic‐like features, and administering validated self‐report measures. Finally, evidence‐based strategies for both pharmacologic and behavioral management are outlined. The first‐line migraine prophylactics are not indicated for PD, and the selective serotonin re‐uptake inhibitors used to treat PD are not efficacious for migraine; thus, separate agents are often required to address each condition. Core components of behavioral treatments for PD are reviewed, and their integration into clinical headache practice is discussed.     

Iron deposition in pain-regulatory nuclei in episodic migraine and chronic daily headache by MRI

Background.— Progression of migraine toward a more disabling chronic form of at least 15 days/month is linked with frequency of attacks. Magnetic resonance imaging (MRI) findings of iron accumulation in the brain, especially in periaqueductal gray and red nucleus, have been correlated with both duration of illness and frequency of attacks. Methods.— This study therefore evaluated iron deposition as measured with MRI in basal ganglia and pain regulatory nuclei in neurologically healthy control volunteers and in patients with various migraine subtypes: episodic migraine (n = 10) with (n = 4) or without aura (n = 6), and chronic daily headache (n = 11), including medication overuse headache (MOH, n = 8), chronic tension‐type headache (n = 1), and primary chronic migraine (n = 2). The goal was to assess differences in iron deposition among migraine subtypes and controls in the hopes of linking the by‐products of frequent attacks or long duration of illness with these changes. Results.— The study sought to evaluate the tradeoff between sensitivity and specificity in T2 imaging of patients with migraine, and found that only T2 imaging in the globus pallidus was able to distinguish between episodic and chronic migraine, suggesting that this technique may be the most appropriate to assess migraine frequency. Patients with MOH did not demonstrate T2′ shortening. Conclusions.— Because iron accumulation should cause shortening of both T2 and T2′, although the lack of significance in observed T2′ difference could be due to increased variance in T2′ the measurement, these results suggest that a mechanism other than increased iron deposition may play a role in the genesis or pathophysiology of MOH.     

Understanding the patient with migraine: the evolution from episodic headache to chronic neurologic disease. A proposed classification of patients with headache

Traditionally, episodic primary headache disorders are characterized by a return of preheadache (normal) neurologic function between episodes of headache. In contrast, patients with chronic headache often do not return to normal neurologic function between headache attacks. This article proposes that the evolution from episodic migraine to chronic headache may parallel the neurologic disruption observed during the progression of an acute migraine attack and that changes in baseline neurologic function between episodes of headache may be a more sensitive indicator of headache transformation than headache frequency alone. Early recognition of nonheadache changes in nervous system function may offer a more sensitive and specific approach to migraine prevention.     

Acute and interictal allodynia in patients with different headache forms: an Italian pilot study

OBJECTIVE: To investigate allodynia in patients with different primary headaches. BACKGROUND: Many migraineurs have allodynia during headache attacks; some may have allodynia outside attacks; allodynia may also be associated with other primary headaches. METHODS: A total of 260 consecutive primary headache patients presenting for the first time at a headache center, and 23 nonheadache controls answered written questions (subsequently repeated verbally) to determine the presence of acute and interictal allodynia. RESULTS: We divided the patients into: episodic migraine (N = 177), subdivided into only migraine without aura (N = 114) and those sometimes or always reporting migraine with aura (N = 63); episodic tension-type headache (N = 28); chronic headaches (headache > or = 15 days/month, N = 52), including chronic migraine, chronic tension-type headache, and medication-overuse headache; and other headache forms (N = 3). Acute allodynia was present in 132 (50.7%), significantly more often in patients sometimes or always suffering migraine with aura, and those with chronic headache forms, compared to patients with migraine without aura and episodic tension-type headache. Interictal allodynia was present in 63 (24.2%) patients, with significantly higher frequency in those having migraine with aura attacks than controls and common migraine patients. CONCLUSIONS: Allodynia is not specific to migraine but is frequent in all headache patients: acute allodynia was reported in half those interviewed and in over a third of patients in each headache category; interictal allodynia was reported by nearly 25%.     

Voxel-based morphometry reveals gray matter abnormalities in migraine

BACKGROUND: Migraine is generally considered a functional brain disorder lacking structural abnormalities. Recent magnetic resonance imaging (MRI) studies, however, suggested that migraine may be associated with subtle brain lesions. OBJECTIVE: We evaluated the presence of global or focal gray or white matter alterations in migraine patients using voxel-based morphometry (VBM), a fully automated method of analyzing changes in brain structure. VBM data also were used to evaluate possible differences between episodic and chronic migraine. METHODS: Twenty-seven migraine right-handed patients and 27 healthy controls were selected for the study. Sixteen patients fulfilled the International Headache Society criteria for episodic migraine and 11 for chronic migraine. MRI scans were analyzed with MATLAB 6.5 and SPM2 software, using VBM method. RESULTS: In comparison with controls, migraineurs presented a significant focal gray matter reduction in the Right Superior Temporal Gyrus, Right Inferior Frontal Gyrus, and Left Precentral Gyrus. Chronic migraine patients, compared to episodic, showed a focal gray matter decrease in the bilateral Anterior Cingulate Cortex, Left Amygdala, Left Parietal Operculum, Left Middle and Inferior Frontal Gyrus, Right Inferior Frontal Gyrus, and bilateral Insula. Considering all the migraine patients, a significant correlation between gray matter reduction in anterior cingulate cortex and frequency of migraine attacks was found. CONCLUSIONS: Our study shows that migraine is associated with a significant gray matter reduction in several of the cortical areas involved in pain circuitry. In addition, we found a significant correlation between frequency of migraine attacks and signal alteration in the Anterior Cingulate Cortex. Our data provide new insight into migraine pathophysiology and support the concept that migraine may be a progressive disorder.     

Cortical Excitability in Chronic Migraine

A proportion of episodic migraine patients experiences a progressive increase in attack frequency leading to chronic migraine (CM). The most frequent external factor that leads to headache chronification is medication overuse. The neurobiological bases of headache chronification and of the vicious circle of medication overconsumption are not completely elucidated. More recently, the same neurophysiological methods used to study episodic migraine were applied to CM and medication-overuse headache (MOH). Studies of cortical responsivity tend overall to indicate an increase in excitability, in particular of somatosensory and visual cortices, reflected by increased amplitude of evoked responses, decreased activity of inhibitory cortical interneurons reflected in the smaller magnetic suppression of perceptual accuracy, and, at least for visual responses, an increase in habituation. In MOH, overconsumption of triptans or NSAIDs influences cortical excitability differently. Generalized central sensitization is suggested to play an important role in the pathophysiology of headache chronification.     

Concepts and mechanisms of migraine chronification

Migraine is a chronic recurrent disorder with episodic manifestations that is progressive in some individuals. Migraine progresses clinically, physiologically, and anatomically. Progression may be a consequence of the mechanisms that generate the migraine attacks (eg, cortical spreading depression) or it may be a function of the activations generated by the attacks (eg, lesions in the periaqueductal gray area), a hypothesis supported by the increase in lesions with attack frequency. Progression may also be partially explained by common genetic or environmental risk factors. Finally, migraine with aura is associated with an elevated Framingham score and with risk factors for cardiovascular disease. Research on this issue is in its infancy and cautions are necessary before extrapolating this information into clinical practice.     

Structural and Functional Neuroimaging in Migraine: Insights From 3 Decades of Research

Modern imaging methods provide unprecedented insights into brain structure, perfusion, metabolism, and neurochemistry, both during and between migraine attacks. Neuroimaging investigations conducted in recent decades bring us closer to uncovering migraine as a multifaceted, primarily central nervous system disorder. Three main categories of structural and functional brain changes are described in this review, corresponding to the migrainous aura, ictal headache, and interictal states. These changes greatly advance our understanding of multiple pathophysiologic underpinnings of migraine, from central “migraine generating” loci, to cortical spreading depression, intimate mechanisms underlying activation of neuronal pain pathways in vulnerable patients, central sensitization, and chronification. Structural imaging begins to explain the complex connections between migraine and cerebral vascular events, white matter lesions, grey matter density alterations, iron deposition, and microstructural brain damage. Selected structural and functional alterations of brain structures, as identified with imaging methods, may represent the foundation of new diagnostic strategies and serve as markers of therapeutic efficacy.     

Post-traumatic stress disorder in episodic and chronic migraine

OBJECTIVE: To assess and contrast the relative frequency of self-reported post-traumatic stress disorder (PTSD) in patients with episodic migraine and chronic/ transformed migraine. BACKGROUND: Several risk factors have been identified as risk factors for chronification of headache disorders. Childhood abuse has been suggested as a risk factor for chronic pain in adulthood. In addition depression, as well as several other psychiatric disorders, are co-morbid with migraine. Recent data suggest that PTSD may be more common in headache sufferers than in the general population. METHODS: This was a prospective, pilot study conducted at a headache center. Adult subjects with episodic, chronic, or transformed migraine were included. Demographic information, depression history, body mass index (BMI), and headache characteristics were obtained. PTSD was assessed using the life events checklist (LEC) and the PTSD checklist, civilian version (PCL-C). We contrasted the data from episodicmigraineurs and chronic/transformed migraine participants (CM) and conducted multivariate analyses, adjusting for covariates. RESULTS: Of the 60 participants included, 91.7% were female with a mean age of 41.4+/-12.5 years old. EM was diagnosed in 53.3% and CM in 46.7%. The mean BMI was not significantly different between groups. In contrast, the relative frequency of depression was significantly greater in subjects with CM (55.2%) than EM (21.9%, P=.016). There was no significant difference in the percentage of participants reporting at least 1 significant traumatic life event (LE) or in the mean number of traumatic LEs between EM and CM participants. However, the relative frequency of PTSD reported on the PCL in CM (42.9%) was significantly greater as compared to EM (9.4%, P=.0059. After adjusting for depression and other potential confounders, the difference remained significant P=.023). CONCLUSION: PTSD is more common in CM than in episodic migraineurs. This suggests that PTSD may be a risk factor for headache chronification, pending longitudinal studies to test this hypothesis.     

The Prevalence of Neck Pain in Migraine

(Headache 2010;50:1273‐1277) Objective.— To determine the prevalence of neck pain at the time of migraine treatment relative to the prevalence of nausea, a defining associated symptom of migraine. Methods.— This is a prospective, observational cross‐sectional study of 113 migraineurs, ranging in attack frequency from episodic to chronic migraine. Subjects were examined by headache medicine specialists to confirm the diagnosis of migraine and exclude both cervicogenic headache and fibromyalgia. Details of all migraines were recorded over the course of at least 1 month and until 6 qualifying migraines had been treated. For each attack, subjects recorded the presence or absence of nausea as well as the intensity of headache and neck pain (graded as none, mild, moderate, or severe). Results.— Subjects recorded 2411 headache days, 786 of which were migraines. The majority of migraines were treated in the moderate pain stage. Regardless of the intensity of headache pain at time of treatment, neck pain was a more frequent accompaniment of migraine than was nausea (P < .0001). Prevalence of neck pain correlated with chronicity of headache as attacks moved from episodic to chronic daily headache. Conclusions.— In this representative cross‐section of migraineurs, neck pain was more commonly associated with migraine than was nausea, a defining characteristic of the disorder. Awareness of neck pain as a common associated feature of migraine may improve diagnostic accuracy and have a beneficial impact on time to treatment.     

Expanding Access to Triptans: Assessment of Clinical Outcome

Objective.— To evaluate whether access to more liberal quantities of rizatriptan improves clinical outcome in patients with episodic migraine.
Background.— Currently many pharmacy benefit programs limit the number of triptan tablets/injections per month based on perceived cost savings and the belief that too-frequent use of triptans may lead to medication overuse headache and headache chronification.
Methods.— This observer-blind, randomized, parallel-group study enrolled 197 subjects with migraine with or without aura. Subjects completed a 3-month baseline period to establish migraine frequency and then were randomly assigned to receive 9 (formulary limit [FL]) or 27 (clinical limit [CL]) tablets of 10 mg rizatriptan orally disintegrating tablet (ODT) per month for 3 months. The primary endpoint was change in the mean number of migraine days from the baseline to treatment period.
Results.— There was no statistically significant difference between the FL and CL groups in mean number of migraine days (FL-CL LS mean: −0.08 [−0.39, 0.23]; P  = .613). Subjects in the CL group treated attacks at lower headache severity. No CL subjects were reported to have developed chronic migraine despite utilization of greater than 10 rizatriptan ODT tablets per month. Rizatriptan was generally well tolerated by both groups.
Conclusion.— Providing a greater quantity of rizatriptan ODT 10 mg did not reduce the number of migraine days compared with providing 9 tablets per month for this population with episodic migraine with a frequency of 3-8 migraines per month. Regardless of quantity provided, rizatriptan was generally well tolerated.     

Coping styles of headache sufferers

Psychological factors are important in the chronification and aggravation of headaches. We studied 90 patients suffering from migraine, chronic daily headache (CDH) evolved from migraine, and episodic or chronic tension-type headache (TTH). Emotional, cognitive, and behavioral pain coping were assessed using the Kiel Pain Inventory (KPI), Beck's Depression Inventory, the State-Trait-Anxiety Inventory, and Quality of Life Questionnaire. In addition, the clinical course of headache was analyzed using a validated headache diary. The results were as follows. Firstly, the KPI is reliable internally for the assessment of pain-coping strategy employment among headache patients. Secondly, migraine sufferers were characterized by pronounced psychological abnormalities during the headache phase, demonstrating a less adaptive coping behavior. This was in contrast to the TTH patients, who showed more general distress manifesting in elevated anxiety and lower quality of life. The only factor which appeared to be essential for differentiating between migraine and TTH was the intensity of headache. Thirdly, chronic TTH and CDH evolved from migraine demonstrated more pronounced psychological disabilities and more severe clinical courses of headaches than episodic TTH or nontransformed migraine. The predictor variable for transformation of migraine was impairment of well-being/quality of life, and for transformation of TTH, the frequency of headaches and depression. Finally, analgesic misuse seems to be less important for chronification and transformation of headaches than the degree of psychological disability. This study draws attention to the role of psychological factors in the chronification of TTH and transformation of migraine and provides some recommendations for the behavioral treatment of chronic headaches.     

Chronic daily headache. How should it be included in the IHS classification?

A number of patients attending specialty headache centers complain of very frequent, almost continuous or continuous headaches, which are usually grouped together under the term chronic daily headache , a category which does not appear in the International Headache Society (IHS) classification. On the basis of the IHS criteria, these patients can only be classified as having a chronic tension-type headache with the possible addition of migraine, if migrainous attacks are superimposed on the "background" headache. However, several studies have demonstrated that most patients with chronic daily headache originally suffered from migraine and that their migraine has transformed, in the course of time, into a chronic headache picture in which isolated migraine attacks may or may not persist. Despite some differences in the personal opinions of authors involved in the care of patients with chronic daily headache, some views seem to be generally accepted: (1) the great majority of chronic daily headaches are transformations of an original episodic migraine and cannot be included in the chronic tension-type headache category, (2) the current IHS classification does not allow many patients presenting with chronic daily headache to be classified correctly, (3) an important nosological category (transformed migraine) has emerged from all the studies on this subject, (4) it is impossible to diagnose transformed migraine merely by "photographing" the picture of single attacks. Although some theoretical problems remain unresolved, it seems to us that the next revision of the IHS classification can no longer ignore the existence of chronic daily headache.     

Duration of migraine is a predictor for response to botulinum toxin type A

OBJECTIVE: To identify the clinical characteristics and/or injection parameters that predict a favorable response to botulinum toxin type A in patients with episodic and chronic migraine. BACKGROUND: There is emerging scientific and clinical evidence to support the utility of botulinum toxin type A (BoNT-A) in the prophylaxis of episodic and chronic migraine headache. However, the patient characteristics and injection strategies that predict a favorable treatment response are unknown. METHODS: We conducted a prospective, open-label study on 74 patients from our clinic receiving BoNT-A for episodic or chronic migraine. For all patients, migraine-related disability (Migraine Disability Assesment [MIDAS]), headache frequency, and average headache intensity were obtained at baseline and at 3 months post-BoNT-A. Information regarding demographic characteristics and injection parameters was also collected. RESULTS: Sixty-one patients met the study criteria and were available for 3-month follow-up. At the 3-month follow-up visit, the mean MIDAS scores of the 61 qualified study patients had decreased from 102 at baseline to 49 (52% decrease, P<.001). The mean number of headache days was reduced from 60 to 39 (P<.001), and the mean headache intensity decreased from 7.6 at baseline to 5.9 (P<.001). Frequency of migraine attacks, presence of analgesic overuse, total BoNT-A dose, and presence of underlying muscle tenderness were not predictive of treatment response. Age and duration of migraine were the only clinical factors significantly predictive of treatment response. Age likely was a predictor only as a consequence of duration of illness as subjects with migraine duration greater than 30 years were significantly less likely to respond to treatment with BoNT-A. CONCLUSION: BoNT-A may be effective in decreasing headache frequency, headache intensity, and headache-related disability in episodic and chronic migraine patients. Duration of illness emerged as a predictor of treatment response. Randomized controlled studies should evaluate headache-related disability as a primary endpoint in patients with episodic and chronic headache.     

The migraine cycle: patient burden of migraine during and between migraine attacks

Migraine is a neurologic disorder characterized by a cycle of attacks, including headache, separated by attack-free periods. Increasingly, episodic migraine is recognized as a disorder that may escalate to chronic migraine, with a frequency of 15 or more attacks per month. Migraine exacts a toll on the quality of life (QoL) of affected individuals, their families, and their workplace. Migraine adversely affects a patient's QoL during an attack, but also has an impact between attacks. This interictal burden on the patient manifests itself as worry in anticipation of the next painful attack and concern over its possible adverse impact on future plans or activities. The high prevalence of migraine, 12% in industrialized countries and approximately 28 million people in the United States, is considered a low estimate. Patients with disruptive migraines frequently overuse self-prescribed medications or may postpone a visit to a physician, which delays accurate diagnosis and appropriate treatment for migraine. Consequently, migraine remains underdiagnosed and undertreated. An extensive literature search of migraine reviewed its associated disability and reduced QoL during, and especially between, attacks. Assessment tools to evaluate the interictal burden on QoL, and to help in migraine diagnosis and patient-physician communication, are readily available. Nevertheless, patients with frequent and recurring migraines, who suffer a reduced QoL, continue to be underrecognized and undertreated. This segment of the migraine population could benefit from preventive therapy.     

Assessment of migraine disability using the migraine disability assessment (MIDAS) questionnaire: a comparison of chronic migraine with episodic migraine

BACKGROUND: Chronic migraine is the most common type of chronic daily headache seen in headache tertiary care centers. Most patients with chronic migraine report their ability to function and feeling of well-being as severely impaired. OBJECTIVE: To measure the headache-related disability of patients with chronic migraine using the Migraine Disability Assessment (MIDAS) Questionnaire, comparing it with that obtained in a control group of patients with episodic migraine. METHODS: The clinical records of 703 patients with chronic daily headache treated in a headache specialty clinic were reviewed to identify 182 with chronic migraine who were evaluated using the MIDAS at their initial visit. Our control group consisted of 86 patients with episodic migraine. RESULTS: Of the 182 patients with chronic migraine, 127 (69.8%) were overusing acute-care medication. Patients were predominantly women (72.5%), with a mean age of 38.3 years. The group with episodic migraine consisted of 59 women (68.6%), with a mean age of 36.1 years. No statistically significant demographic differences were observed between the two groups. The group with chronic migraine had more total headache days over 3 months (66.7 versus 15.5, P<.001), missed more days of work or school (5.3 versus 2.3, P =.0007), had more reduced effectiveness days at work or school (11.9 versus 4.6, P =.0001), missed more days of housework (16.5 versus 3.3, P<.0001), and missed more days of family, social, or leisure activities (7.0 versus 5.5, P =.03). The group with chronic migraine was more likely to be in MIDAS grade IV (64.3% versus 43.2%, P =.001), reflecting the great likelihood of severe disability in this group. The average total MIDAS score was 34.9 in the group with chronic migraine versus 19.3 in the group with episodic migraine (P<.001). CONCLUSION: In subspecialty centers, patients with chronic migraine demonstrate remarkable impairment of their daily activities and are severely burdened by their headache syndrome, reflected by their high MIDAS scores. The chronicity and pervasiveness of migraine thus is associated with increased functional impairment as well as increase in headache frequency.     

Economic Burden of Transformed Migraine: Results From the American Migraine Prevalence and Prevention (AMPP) Study

Objective.— To evaluate the impact of incident transformed migraine on health care resource utilization, medication use, and productivity loss. In addition, the study estimates the total direct and indirect costs associated with transformed migraine. Background.— Emerging evidence indicates that migraine may be a chronic progressive disorder characterized by escalating frequency of headache attacks, often termed transformed migraine. Little is known about the economic impact of transformed migraine. Methods.— AMPP is a 5‐year, national, longitudinal survey study of headache in the US. The study utilized data from the 2006 follow‐up survey based on an initial sample of 14,544 adults identified as having migraine in either the 2004 screening or 2005 baseline survey. A diagnosis of migraine was assigned based on criteria proposed by the International Classification of Headache Disorders, 2nd Edition. Participants completed self‐administered, validated questionnaires on headache features, frequency, impairment, resource use, medication use, and productivity loss. Direct and indirect headache‐related costs were estimated using unit cost assumptions from the PharMetrics Patient‐Centric database, wholesale acquisition costs (Red Book), and wage data from the US Bureau of Labor Statistics. Those who developed transformed migraine were compared with those who did not develop transformed migraine in the 1‐2 year interval between screening/baseline and follow‐up. Results.— A total of 7796 (54%) identified migraine cases completed the 2006 follow‐up survey. Of those cases, 359 (4.6%) developed transformed migraine. Participants who developed transformed migraine reported significantly more primary care visits, neurologist or headache specialist visits, pain clinic visits, and emergency room visits compared with participants whose migraine remained episodic. Hospital nights and urgent care visits did not reach statistical significance. Transformed migraine participants reported significantly more time missed at work or school because of headaches and more time where work or school productivity was reduced by >50% in the previous 3 months because of headaches. Average per‐person annual total costs, including direct and indirect costs, were 4.4‐fold greater for those who developed transformed migraine ($7750) compared with those who remained episodic ($1757). Conclusion.— Transformed migraine exacts a significantly higher economic toll on patients and health care systems compared with other forms of migraine. Our findings support the need to prevent migraine progression and to provide appropriate management and treatment of transformed migraine.