The impact of migraine
Migraine is a remarkably disabling condition, although unpredictable and heterogeneous in frequency, duration and severity. It can be difficult to manage in primary care, where it is under-recognised, under-diagnosed and under-treated. Proposals have been made that migraine care could be improved by incorporating assessments of migraine impact into management strategies. Research has shown that measuring headache-related disability, together with assessments of pain intensity, headache frequency, tiredness, mood alterations and cognition can be used to assess the impact of migraine on sufferers’ lives and society. From this research two simple and brief impact tools were developed; the Migraine Disability Assessment (MIDAS) Questionnaire and the Headache Impact Test (HIT). Both tools are scientifically valid measures of migraine severity and have the potential to improve communication between patients and their physicians, assess migraine severity and act as outcome measures to monitor treatment efficacy. Each of these tools offers its own advantages. For example, HIT was designed for greater accessibility and has a wider coverage of the spectrum of headache than MIDAS. Impact tools are also being increasingly recommended as part of generalised headache management guidelines to produce an individualised treatment plan for each patient in concert with other clinical assessments. It is not possible as yet to unequivocally recommend the optimal impact tool for use in primary care, but it should be usable by GPs, pharmacists, nurses and patients, and for research purposes.
Migraine is a common, debilitating neurological disorder that affects about 8–12% of the general population. It is more prevalent in women than in men and in Caucasians than in Black and Asian races. Migraine attacks consist of moderate to severe headaches, which are typically throbbing, one-sided and aggravated by physical activity. The headache is usually accompanied by photophobia and/or phonophobia and nausea, and less frequently by vomiting and aura symptoms. Attacks occur on average about once or twice a month, last for about 24 hours, and are separated by symptom-free intervals. Migraine attacks result in significant reductions in sufferers’ health-related quality of life (HRQoL) compared with normal healthy subjects. However, migraine is an unpredictable, heterogeneous disorder and attacks vary widely in frequency, duration, severity and reported symptoms.
Due to this variability, migraine can be difficult to manage in primary care. In clinical practice, migraine is under-estimated, under-diagnosed and under-treated, leading to many patients dropping out from care (Figure 1). A recent study in the UK showed that 86% of migraine sufferers had consulted their physician at some time for treatment. However, 37% of sufferers had dropped out, leaving 49% as currently consulting. Studies in the USA and France indicated that about half of all migraine sufferers who consulted their general practitioners did not receive a correct diagnosis. Patients may not receive appropriate treatment even when they do consult and are diagnosed correctly. International and UK studies have shown that only a minority of migraine sufferers take prescription medications and patient satisfaction with their usual analgesic acute medications is low.
A range of initiatives has been set up to improve migraine care, by encouraging migraine patients to consult their physicians and for physicians to improve their diagnostic and treatment strategies. Several of these involve assessing the impact of migraine on sufferers’ lives, and using this information to facilitate management strategies. This article reviews the rationale for, and development of, tools that assess migraine impact and their potential roles in general practice.
Research into the impact of migraine
The impact of migraine can be considered as the objective effects of the illness on sufferers’ lifestyles, including their work and leisure activities, rather than subjective effects expressed as symptoms and HRQoL. Impact has great similarities to the World Health Organization’s definition of disability: "a restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being". Studies from the USA, Canada and Japan have shown that migraine causes significant disability in its sufferers, with two thirds or more reporting at least mild disability and a third or more reporting moderate to severe disability. In a UK study, two thirds of migraine sufferers reported that migraine disrupted their lives, with three quarters having to lie down during attacks (Table 1). A second study indicated that between one third and two thirds of migraine sufferers in the UK (an estimated 1.9–3.8 million people) felt that they were not in control of their migraine and the way it affected their day-to-day lives.
The consequences of migraine impact are seen in patient’s lifestyles, including employment, unpaid work and family and leisure activities. The loss of these activities has been quantified in a series of studies. In the USA, each working migraine sufferer missed an average of 4.4 days of work per year and the equivalent of 12 further days due to reduced productivity during attacks. In the UK, half of sufferers reported missing work and over two thirds reported difficulty performing work during attacks (Table 1). Migraine may even lead to unemployment. In a Health Maintenance Organisation in the USA, the unemployment rate was 2- to 4-fold higher in severely affected migraine sufferers than in the general population. School and college work is also affected in young migraine sufferers. In a Scottish study, children with migraine were absent from school for significantly longer periods than those without migraine (7.8 days versus 3.7 days per year, P<0.0001). This personal burden of migraine is reflected in an economic burden on society. Indirect costs (due to work absence and reduced work productivity) are very large for migraine, being estimated at £950 million in the UK in 1991. These costs are very much higher than the direct costs due to medical care, estimated at £23 million in 1990. Although direct medical costs for migraine have increased since 1990, partly due to the introduction of the triptan drugs, indirect costs still provide the main economic burden of the illness.
Migraine also affects unpaid work and family and leisure activities. In a UK study, 90% of migraine sufferers reported that they postponed their household work during an attack (Table 1). Several studies have shown that migraine attacks commonly result in the cancellation of social events, and affect relationships with partners, children, friends and other people.
Migraine is therefore a remarkably disabling condition, with most sufferers reporting significant impact associated with their attacks in all areas of their lifestyles. Recent research has focused on the use of impact assessments to measure the severity of migraine in comparison with other assessments.
Assessing the impact of migraine
Migraine attacks vary in severity from moderate pain, with no activity limitations, to severe pain with prolonged incapacitation. To measure the impact of migraine, parameters must be defined that capture the personal burden on the sufferer and the economic burden on society. Following this, a scientifically valid tool needs to be developed to capture this information in a way that is simple to use and clinically relevant.
Rationale for using impact tools
Pain intensity is the most important aspect of migraine to the individual sufferer. Sufferers report headache pain more frequently than all other migraine symptoms and most patients consulting their physicians do so for pain relief. However, economic studies have shown that headache-related disability is the most important determinant of migraine’s societal impact in economic terms. Assessments of pain and disability were therefore included in initial studies assessing the impact of migraine.
The Chronic Pain Index (CPI) was developed to measure the severity of a number of pain conditions, including headache, in primary care patients. Results showed that pain intensity and disability measures formed a reliable hierarchical scale whereby pain intensity scaled the lower range and disability the upper range of severity. Four severity grades were identified that covered the whole pain spectrum. When the CPI was tested on 740 primary care headache patients over a 2-year period, the severity grade was directly related to the impact of the headache on the individual and the direct and indirect economic costs (Figure 2). There was approximately 3–4 fold greater individual impact, direct costs and indirect costs (assessed as the unemployment rate) for patients in the highest severity grade compared to those in the lowest grade. These results were confirmed in a study conducted in migraine patients who assessed the pain and disability associated with their most recent attack.
Using the CPI as a model, the Headache Impact Questionnaire (HImQ) was developed to measure headache impact. This was a relatively complex, 16-item questionnaire assessing headache frequency, pain intensity and disability, the latter measured as total lost time in employment, household work and non-work activities. Studies showed that the HImQ was a scientifically reliable and valid measure of migraine severity. However, it was complex to score, requiring mathematical equations, and was not intuitive to use as it was based on a composite of pain, frequency and disability measures. It was therefore not suitable for use in primary care, but has proved to be an excellent research tool.
This research did indicate that it was possible to assess the impact of migraine using scientifically valid questionnaires. The next challenge was to develop simple but accurate and comprehensive questionnaires that could be used in the primary care setting.
Development of impact tools for use in primary care
Two tools have been developed to assess the impact of migraine, both partly based on the HImQ. However, they use quite different strategies to achieve their goals. The Migraine Disability Assessment (MIDAS) Questionnaire assesses impact as a static measure of disability, while the Headache Impact Test (HIT) uses a global assessment of impact. It should be noted that both questionnaires assess headache in general, rather than migraine specifically, and so have potential application to the whole field of headache management.
The Migraine Disability Assessment (MIDAS) Questionnaire
MIDAS is a paper-based questionnaire, designed to be accessible at physicians’ surgeries and pharmacies. Migraine sufferers answer five questions in three activity domains covering the previous 3-month period (Figure 3). They score the number of lost days due to headache in employment, household work and family and social activities. Sufferers also report the number of additional days with significant limitations to activity (defined as at least 50% reduced productivity) in the employment and household work domains. The total MIDAS score is obtained by summing the answers to the five questions as lost days due to headache. This can sometimes be higher than the actual number of lost headache days due to any one day being counted in more than one domain. The score is categorised into four severity grades: Grade I = 0–5 (defined as minimal or infrequent disability); Grade II = 6–10 (mild or infrequent disability); Grade III = 11–20 (moderate disability); Grade IV = 21 and over (severe disability); Two other questions (A and B) are not scored, but were designed to provide the physician with clinically relevant information on headache frequency and pain intensity.
MIDAS was tested extensively and shown to have face validity (i.e. meets physicians’ conceptions of important clinical criteria) and to be reliable, accurate, easy to use and score and intuitively meaningful to physicians. These features support its suitability for use in clinical practice. MIDAS has been proposed as an aid to communication between patients and healthcare professionals, as an aid to referral for primary care physicians, as a means of specifying treatment by using it to stratify patients according to their treatment needs, as an outcome measure and as a public health initiative to coordinate public policies for migraine management.
The MIDAS Questionnaire has several strengths. It has proved to be an effective aid to communication between physicians and their migraine patients with regard to disability, a subject often overlooked in conventional consultations. MIDAS is now widely used for this purpose by headache specialists and neurologists. Small clinical studies have shown that MIDAS is sensitive to change, and can be used as an outcome measure in the follow-up of patients during treatment. However, these data require corroboration in large scale clinical trials.
However, MIDAS also has several weaknesses. It does not assess the full spectrum of headache, covering only about 35% of the range between moderate and severe intensity. This may be due to its reliance on a single measure (disability). Additionally, the MIDAS grade score may not indicate the true medical need of patients. In the author’s clinical practice, many needy patients scored as Grade I, theoretically with little disability. A US study has shown that about 10% of MIDAS Grade I headache sufferers had more than six severely painful headaches per year. On the other hand, patients with frequent headaches, e.g. chronic daily headache, tend to all score as Grade IV. Some physicians have suggested that MIDAS is weighted towards the measurement of headache frequency over disability. The use of MIDAS as a tool to specify treatment according to the patient’s disability grade has proved to be controversial, despite some evidence from a large clinical trial, and few physicians use it in this way.
The Headache Impact Test (HIT)
HIT was first developed as a web-based test, designed to be accessible to all physicians and headache sufferers through the Internet. Questions are not printed on forms in advance. Rather, it is a dynamic questionnaire (Figure 4), with items derived from four validated headache questionnaires sampling all areas of headache impact (the Headache Disability Inventory [HDI], the HImQ, the MIDAS Questionnaire and the Migraine-Specific Quality of Life Questionnaire [MSQ]). Patients are questioned until clinical standards of score precision are met. Internet-HIT matches the questions asked to each patient’s severity level. In practice, five questions are sufficient to grade the majority of headache sufferers. Clinical standards of accuracy were met by 98% of migraine sufferers, and 97%, 87% and 61% of people with severe, moderate and mild headaches, respectively, completing five or fewer questions. In an extensive testing study in over 19,000 headache sufferers in the USA, Internet-HIT was shown to be reliable and valid, and covered the whole spectrum of headache. Coverage was similar to that reported for HImQ and much greater than that of MIDAS. Results showed that migraine had greater impact on sufferers’ lives than most other headaches. Internet-HIT differentiated sufferers on the basis of diagnosis and characteristics such as headache severity and frequency. It took only 1–2 minutes to complete, and its use motivated headache sufferers to seek medical care and facilitated headache-related communication between patients and their physicians.
HIT-6 is a paper-based, short-form questionnaire based on the Internet-HIT question pool, designed for people without access to the Internet (Figure 5). Six questions cover pain severity, loss of work and recreational activities, tiredness, mood alterations and cognition. Each question is scored on a five-point scale, with the scores being added to produce the final score. HIT-6 scores are categorised into four grades, representing minimal, mild, moderate and severe impact due to headache. Studies have shown that HIT-6 is reliable and valid, and can be used to identify migraine sufferers and customise therapy according to illness severity.Also, HIT-6 scores were directly related to self-reported hours of workplace productivity loss due to headache. Internet-HIT and HIT-6 scores compared well to each other when the two forms of the questionnaire were tested on a group of headache sufferers.
Both the MIDAS and HIT tools provide scientifically reliable and valid measures of headache impact, and show great promise for wide utility in clinical practice. However, both forms of HIT appear to have certain advantages over MIDAS. HIT has the brevity of a short-form questionnaire but has the accuracy required for measuring individual patients at all levels of impact. This may be due to its wider range of questions compared to MIDAS, which scores time lost due to headache only. HIT is also more widely accessible than MIDAS, designed to be used by everyone through the Internet and as a paper-based form. However, HIT was developed more recently than MIDAS and has so far not been used in clinical practice to the same extent. So far, only MIDAS has exhibited sensitivity to change and can therefore be used to monitor the outcome of therapy. HIT has not been tested for this, but is expected to also have this feature. Future work will define further the place of each of these impact tools in primary care, and such studies are currently underway with HIT.
Strategies for managing migraine using impact measures
Although impact measures for migraine are a recent development, they have been adopted widely by many opinion leaders in the field of headache. Both MIDAS and HIT have been proposed to have a wide potential for use in clinical practice. Impact measures have been incorporated in several initiatives to develop guidelines for the management of migraine in primary care, including those issued by the Migraine in Primary Care Advisors (MIPCA) in the UK and the Headache Consortium and the Primary Care Network in the USA.
These three sets of guidelines have several features in common. They use assessments of migraine impact or disability in the initial evaluation of patients and recommend that treatment should be tailored to the patient’s individual needs. Additionally, patients who have disabling migraine are recommended to have access to migraine-specific therapies from the outset. Assessing migraine impact has obvious applications in these areas of management and future migraine guidelines are likely to incorporate impact tools significantly.
The Migraine in Primary Care Advisors’ (MIPCA) Guidelines
In 1997, MIPCA was the first organisation to advocate assessing the impact of migraine as part of its management strategy, before clinically valid impact tools had been developed. Revised guidelines were issued in 2000. MIPCA advocates an individualised approach to care, treatment being prescribed according to each patient’s needs. Factors considered include the nature of the patient’s attacks, the impact of headache on the individual’s life and the demands of the patient’s lifestyle.
The MIPCA guidelines are illustrated in Figure 6. At the initial consultation, the physician is recommended to conduct a diagnostic assessment and to take a careful history covering the nature of the headaches, previous treatments taken and the impact on the patient’s life. Patients who experience up to four attacks per month are given acute therapy with a simple analgesic (with or without an anti-emetic) or an oral triptan if analgesics have been used unsuccessfully in the past. Nasal spray or subcutaneous triptan formulations may be considered if the patient has difficulties with oral therapies or requires a fast therapeutic effect due to the demands of their lifestyle.
If the initial therapy is unsuccessful, an alternative triptan may be provided. For patients who fail on this therapy, and for migraine patients with four or more headaches per month, prophylactic treatment is recommended, together with additional acute treatment for breakthrough attacks. Migraine patients who fail on this treatment, and those diagnosed with chronic daily headache (CDH), may require referral to a specialist physician.
Migraine is a remarkably disabling condition, but is not always managed effectively in primary care. Barriers to migraine care exist for both general practitioners (GPs) and patients, leading to under-consultation, under-diagnosis and under-treatment. Patients often do not rate non-headache symptoms as medical and tend not to communicate the disability they suffer. In two studies with a total of 105 physicians in North America and Europe, only about one third of patients were reported to volunteer information about their headache-related disability. It can be difficult for the physician to go through protocols with patients. Headache diaries, though useful, need reinforcement with other measures and GPs need to know that migraine causes disability. In the same North American / European studies discussed above, physicians reported that they recorded symptoms related to diagnosis (e.g. pain intensity and associated symptoms) rather than information on headache-related disability. Similar results have been reported from the UK. In a recent study of 33 UK GPs, only 54% took the impact of migraine into consideration on diagnosis as opposed to 81% who assessed family history, 93% who assessed symptomatology and 90% who assessed trigger factors. Only 24% of the physicians felt that migraine always had an impact on the patient’s life. Such assessments of impact were subjective, as none of the GPs was aware of the MIDAS or HIT impact tools. Overall, measuring the impact of migraine is likely to aid the initial assessment of migraine, and improve treatment delivery.
Research has shown that the impact of migraine can be measured using assessments of some or all of pain severity, headache frequency, limitations to work and leisure activities, tiredness, mood alterations and cognition. Tools that address migraine impact are now available and are being brought into clinical use. The MIDAS Questionnaire assesses disability only, as lost time in employment, unpaid work and family and leisure activities, whereas HIT assesses a global range of impact, including pain intensity, disability and other items, which can be tailored to the individual in Internet HIT.
Neither MIDAS nor HIT is used widely in UK general practice. MIDAS is used in specialist practices, where it has proved to be effective in improving communication between physicians and their patients, and as a measure of treatment outcome. However, it has not proved as useful when tested in UK general practice, partly due to the overlapping nature of the questions. Patients too, are unsure of it. Little or no feedback was received when MIDAS was published in the Migraine Action Association Newsletter and tested in pharmacies in the UK. HIT has not been used significantly to date in UK clinical practice.
An impact tool can be recommended for the primary care of migraine and its desirable attributes identified. It should be a self-administered form that is able to be summarised briefly. Open questions should be used, rather than a ‘ticking boxes’ approach. The tool should be used in the physician’s initial assessment to aid in the initiation of appropriate management strategies. It should also be able to measure the efficacy of medications and needs to be discriminating, e.g. impact testing may be used as a tool to measure if a treatment is working for a patient, rather than merely if it is not. If the treatment is working, the patient should remain on that same treatment. In practice, the impact tool should be integrated with other assessments of migraine symptoms. Finally, impact tools need to be refined and shown to work in general practice, where they can be used to review patient costs and potential cost savings of treatments. From the patients’ viewpoint, it is important to ask questions about migraine impact, but this should be taken as part of the whole clinical judgement of patients’ needs.
Migraine impact is probably the most important headache assessment for the patient. Impact tools should therefore be widely accessible to patients at home, in pharmacies and GPs’ waiting rooms and with nurse consultants, e.g. in well woman clinics. They should also have positive effects on the GP’s practice, highlighting that migraine is a disabling illness and raising its profile in primary care. However, education of both patients and physicians on migraine impact and the use of impact tools will be necessary for their successful introduction. The initial launch of impact tools is probably best achieved through headache clinics and GPs with an existing interest in treating headache.
Both MIDAS and HIT meet many of the above desirable attributes for an impact tool suitable for use in primary care. They are both brief, simple to use and score, and have demonstrated scientific validity and clinical utility. However, the greater accessibility of HIT (by design for use on the internet and as a paper-based from) and its greater coverage of the spectrum of headache patients, irrespective of their illness severity, may make it the optimum tool. With MIDAS, there is also the danger of patients with infrequent but disabling headache being categorised as having minimal disability, and so being overlooked.
Recently published guidelines for the management of migraine have included assessments of migraine impact in the evaluation of migraine severity and treatment choice, in conjunction with traditional history taking and symptom evaluation. These guidelines advocate an individualised approach to care, where patients are managed according to their illness severity and lifestyle needs. Patients are educated and encouraged to play a key role in the care decisions made. However, previously published guidelines for migraine management in many countries, including the UK, USA and Germany make no mention of assessing migraine impact in the evaluation of patients. Nevertheless, impact assessments have a central role in the management of migraine and should be used in the development of new guidelines for primary care in the UK.
In conclusion, the assessment of migraine impact is important in UK primary care. The use of impact tools can improve communication between physicians and their patients, aid in the assessment of migraine severity and the production of an individualised treatment plan in concert with other clinical assessments, and in the monitoring of the response to therapy. In the future, impact tools will be used in generalised headache management guidelines for the UK. As yet, it is not possible to unequivocally recommend the optimal impact tool, but it should be usable by GPs, pharmacists, nurses and patients, and should also be useful for purposes of research.
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