Abstract
Background and aim
Health administrators, policy makers, and educators have attempted to increase guideline adherence of migraine medications while reducing inappropriate use of opioid- and barbiturate-containing medications. We evaluated the burden of migraine and proportion of guideline-concordant care in a large, national health care system over time.
Methods
We conducted a time-series study using data from the Veterans Health Administration (VHA) electronic health record. Veterans with migraines were identified by ICD-9 code (346.X). Prescriptions and comorbid conditions were evaluated before and after migraine diagnosis. Chi-square tests and logistic regression were performed.
Results
A total of 57,064 veterans were diagnosed with migraine headache (5.3%), with women significantly more likely diagnosed (11.6% vs. 4.4%,
Conclusions
The burden of migraines is increasing within the VHA, with a corresponding increase in the delivery of guideline-concordant acute and prophylactic migraine-specific medication.
Introduction
Population-based studies report one-year migraine prevalence rates of 0.6%–16.7% in men and 1.5%–33% in women, and across-studies rates are two times higher in women compared to men (1). Migraine headaches are a common cause of impairment and days away from work; people with migraines miss on average four days of work a year (2) and cost the United States (US) an estimated $13 billion a year (3). Veterans are particularly vulnerable to developing migraines because of their relatively high rate of traumatic brain injury (TBI).
Migraine care may provide an opportunity to explore variation and quality of pain management among veterans since guidelines for appropriate use of antimigraine medications are well established in primary care (4,5), emergency department (6), as well as specialty (6,7) settings. Current guidelines recommend offering migraine-specific agents (such as serotonin 5-hydroxytryptamine (5-HT1B/1D) agonists, or triptans) in moderate or severe acute migraines or in people who do not respond adequately to nonsteroidal anti-inflammatory drugs (NSAIDs). For people with chronic migraines, a daily prophylactic antimigraine analgesic is recommended. Opioids, barbiturates, and ergotamine-related medications have been discouraged because of risk of side effects and/or dependence.
We sought to explore the prevalence of migraine and other headache diagnosis in the Veterans Health Administration (VHA) over time and the quality of migraine pain management by examining recommended and non-recommended medications among veterans of the recent wars in Iraq and Afghanistan receiving care in VHA facilities. We hypothesized that the prevalence of migraine diagnoses would increase and, as sumitriptan has been available as a generic medication since 2009, that the use of triptans would increase. Finally, we hypothesized that the use of opioids, ergotamines, and barbiturates would decrease, as guidelines have discouraged the use of those medications.
Methods
Patients and settings
Data on eligible veterans were linked with VHA administrative and clinical data contained within the VHA National Patient Care Database, Decision Support Systems, and the Corporate Data Warehouse. These databases provide health care utilization and cost data, health encounters, and coded diagnostic and procedure data (International Classification of Disease (ICD)-9) associated with all VHA inpatient and outpatient encounters.
Study population
Data for this study were part of the VHA funded Women Veterans Cohort Study (WVCS) (8) and were approved by the VHA Connecticut Healthcare System institutional review board. The study population was composed of veterans from the VHA’s Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) roster provided by the Defense Manpower Data Center—Contingency Tracking System Deployment File. The VHA OEF/OIF roster includes information on veterans’ gender, race, date of birth, date of last deployment, and armed forces branch who used VHA services. Data were then linked to the VHA electronic health record from 1 October 2001 to 30 November 2012.
Measures
Migraine cases were identified cross-sectionally (year that migraine diagnosis was first assigned) and a short follow-up time was used. Veterans with migraines across all clinics, including primary care and neurology clinics, were identified by ICD-9 code (346.X) during the period from 1 October 2001 to 30 November 2012. To increase diagnostic accuracy, we counted only those migraine diagnoses coded at least once in an inpatient stay or at least twice in two outpatient visits over an 18-month period. The first of these visits was recorded as the migraine diagnosis date. The year of diagnosis was used to examine temporal trends in the treatment of migraine.
From pharmacy data, opioids, tramadol, triptans, and guideline-recommended migraine-preventive prescriptions (including propranolol, metoprolol, topiramate, valproate, amitriptyline, and venlafaxine) were documented. Any use both in the year before and the year after migraine diagnosis date was calculated for these medications. Use of opioids, tramadol, and/or preventive medications in the year prior was examined.
The independent variables examined in these analyses include age, gender, race/ethnicity, and comorbidities in the form of ICD-9 diagnoses recorded in the inclusion period of one year prior to migraine diagnosis through six months following migraine diagnosis. Comorbidities examined include other headache types, mental health disorders, musculoskeletal disorders (MSDs), hypertension, and TBI. These conditions also required mention in one inpatient visit or two outpatient visits within 18 months.
Statistical analysis
Univariate analyses were conducted to describe the overall sample and the subgroup of veterans with migraines. Logistic regressions explored relationships of migraine with demographic data, medical and psychiatric comorbidity, including documented history of TBI (adjusting for age, gender, and race/ethnicity). Logistic regression was also conducted to analyze the probability of having a triptan prescription in the year following migraine diagnoses. Chi-square tests were conducted for categorical variables to determine associations including gender differences and differences by year of migraine diagnosis.
All migraine diagnoses in the observation period were included in the descriptive and bivariate analyses. The restriction in years (2004–2012) was imposed only for the estimates examined by year of migraine diagnosis. When examining migraine by the individual year in which the diagnosis was made, years 2000–2004 had small numbers of cases causing unstable estimates. Furthermore, for years 2013–2015, data on case counts were still being processed and were incomplete.
Results
Description of veterans with migraines—demographics and comorbidities
Sample description including migraine patients by gender.
Women with migraines were more likely to be black (Chi-square = 1996.31, df = 4,
Crude and adjusted odds ratios in veterans with migraines a .
Adjusted ORs are adjusted for age, sex, and race/ethnicity. OR: odds ratio; CI: confidence interval; AOR: adjusted odds ratio; TBI: traumatic brain injury; PTSD: post-traumatic stress disorder.
New diagnoses of migraine over time
The number of veterans being given a first diagnosis of migraine (while in the cohort) increased over time (Figure 1). Fewer than 1000 were given the diagnosis in 2004 and this has risen to a high of near 9000 cases diagnosed in 2012 (last year with complete data). This absolute increase in cases demonstrates a marked increase in the burden of migraine cases in the VHA.
Number of migraine cases diagnosed per year, by gender.
Treatment of migraines over time with migraine-specific medication: Triptans
Collapsed across all years, 43% of veterans with migraines were prescribed triptans in the year following their diagnosis of migraine. Gender was not associated with triptan prescription (women veterans = 42.66% and men veterans = 42.96%). We observed variability in the proportion of patients receiving triptans by the year of migraine diagnosis (1) (Figure 2(a)). When split by gender, there was a significant increase over time in men veterans with migraines (Chi-square = 19.93, df = 1, (a) Triptan prescription by year of migraine diagnosis by gender. (b) Triptans in the year after migraine diagnosis by race.
Nonspecific medication for treatment of pain: Opioids
While nearly 5% of people with migraines were prescribed opioids in the year following their migraine diagnosis (data not shown), the rates differed by opioid status in the year prior to the migraine diagnosis. Those prescribed opioids in the year prior were more likely to receive opioids after migraine (35–55%), compared with those who had not received them (1.5–3.8%). In the VHA administrative data, it is not possible to determine the diagnosis associated with a given prescription. However, opioids were likely prescribed for other (ongoing) conditions rather than migraine. Almost all veterans with migraines who have been prescribed opioids in the year prior to migraine diagnosis (97.7%) or in the year after (96.4%) had a comorbid MSD. Veterans with MSDs were 3.86 times as likely to receive opioids in the year after migraine diagnosis as those without MSDs.
Tramadol
As observed with opioids, a prescription of tramadol in the year prior to migraine diagnosis was associated with prescription in the year following migraine diagnosis. Rates of tramadol use in the group without prior tramadol prescriptions ranged from 2.2% to 3.0%, whereas the group prescribed tramadol prior to diagnosis had rates of 41.6% to 80%. As seen with opioids, these prescriptions were likely due to other ongoing painful conditions. Tramadol before and after migraine diagnoses were associated with higher rates of MSDs (99.1% and 97.2%, respectively). Veterans with MSDs are 4.85 times as likely to receive tramadol in the year after migraine diagnosis as those without MSDs.
Migraine-prevention medication
Migraine-preventive medications include antihypertensives, antiepileptics, and antidepressants. The use of migraine-prophylactic medications in people with migraine has shown a significant increase over time (Figure 3) from 42.8% to 49.53%. This increase was both in men and women. These increases remained after controlling for age, race, and comorbidities associated with preventive medicine use (e.g. hypertension, epilepsy, unipolar and bipolar mood disorders). Our examination of their frequency of use over time, the relatively low rates of comorbidities for which these medications are primarily prescribed, and adjustment for five key comorbid conditions in multivariable modeling increased our certainty of their use in this sample for migraine prophylaxis.
Preventive medicine by year of migraine diagnosis by gender.
Discussion
We speculate that the marked increase in migraine diagnosis from 2004 to 2012 may be due to several temporal trends: an increase in the rate of OIF/OEF veterans entering the VHA system with TBI, an increased need for treatment, increased availability of triptans since the generic form was released in 2009, and an increased awareness of migraine treatments through educational programs and the literature. Within our population, 11.6% of women veterans and 4.4% of veteran men were given the diagnosis of migraine in 2012. Although the rate of documented migraines in veterans is considerably lower than large population-based US studies, reporting 18.2% in women and 6.5% in men (9), migraines are often underdiagnosed in the clinical setting. For instance, in one survey of 8579 nonprofit health maintenance organization enrollees in Michigan, only 52.9% who met strict criteria for migraines were ever documented with the diagnosis (10).
Hoge et al.’s 2008 seminal study demonstrated that while military personnel who suffered from TBI have increased days missed from work, when adjusting for depression and PTSD, only headaches, not TBI, were associated with poor health outcomes (11). Much of the literature on veteran health explores the relationship and interaction between PTSD and post-concussive symptoms. In our cohort the minority of veterans with migraines suffered from TBI (38% of men and 12% of women) but a substantial proportion had PTSD (68% of men and 48% of women). Therefore, the majority of veterans with migraine likely do not have combat-related post-TBI headaches. The relationship between TBI and migraine has important implications to pathways to care. Primary care providers within the VHA are mandated to screen for TBI through electronic clinical reminders. Unless the veterans directly report having headache or the provider screens for headaches as part of the review of system, many veterans with migraines and without TBI may not be managed appropriately. Systematic headache screening in primary care may improve guideline-concordant care and should be considered for further research.
A significant proportion of veterans were diagnosed with Headache Not Otherwise Specified (NOS) or Other Headache; many of them may suffer from migraine, tension, or cluster headaches and may have been misclassified. We suspect that some of them may have migrainous features such as photophobia or nausea due to post-concussive syndrome and did not quite meet criteria for a primary headache syndrome. Perhaps the relatively smaller proportion of migraines diagnosed in the Veteran population compared to the civilian population is due to the misclassification of migraines. Veterans with migraines may have been misclassified as Headache NOS or Other Headache because of the expediency of diagnosing headaches without considering the criteria of the primary headache syndromes. However, given that the current guidelines recommend specific treatments for specific headache syndromes, perhaps some clinicians were not comfortable with committing to a specific headache diagnosis. We suspect more education is needed for VA providers regarding migraine criteria.
Men and women veterans are given guideline-concordant medications at a markedly higher rate (43% in 2012) compared with civilian populations (15.9%) (12). Rates for appropriate migraine treatment care range from 8% to 67% depending on the clinical setting and in patient characteristics (12–15). In civilian populations, women, young age, higher economic status, higher education, and more-severe migraine symptoms are associated with greater rates of use of first-line agents (15). We hypothesized that an increase in availability of triptans, due to the release of the generic formulation, would lead to the increase of prescription rate; however, this did not prove true. In spite of the marked increase in the number of veterans diagnosed, the proportion of veterans prescribed triptans remained relatively stable over the course of the 12 years of monitoring. We hypothesize that several factors may have contributed to the provider prescribing behavior. Although we do not have information regarding the severity and frequency of migraines, or response to over-the-counter medication, perhaps generic analgesics provided adequate control of a large proportion of migraines. Some VHA medical centers restrict initial prescription of triptans to neurologists, and perhaps the number of providers comfortable with using triptans limits the proportion of triptan prescription. Or perhaps veterans are receiving other medications from outside the VHA system. Furthermore, the relatively higher proportion of guideline concordance within the VHA system compared with civilian care may be due to the centralized, integrated model of care the VHA offers, making it more conducive to disseminating and implementing clinical guidelines.
In addition to the relatively high proportion of use of guideline-concordant medications, veterans generally were not prescribed non-recommended medications. For instance, veterans were newly prescribed opioid and barbiturate medications (1.5–3.8%) at a much lower rate compared to civilians with migraines (18.4%).12 Opioid use in the community setting ranges from 6.4% to 21.2% (16,17), most commonly in the emergency department setting and least commonly in primary care. In the 1990s, barbiturate-based medications were the most commonly prescribed analgesics for migraines in the US (16). In spite of this trend, a very small minority (<1%) of veterans with migraines were prescribed these medications. The increased rate of opioid use among women veterans may reflect an increased utilization of services more generally.
While this study on migraine rates and management among veterans offers interesting insights, limitations of this include migraine case definition that was based on clinical documentation and likely was under-reported. Veterans may live with headaches and if not properly identified they may have been coded for a headache disorder and may not be receiving appropriate treatment. Data regarding the provider who prescribed the medication, the indication of the prescription (many migraine medications may be use for non-migraine indications), and severity of migraine were not available. However, we demonstrated that a small minority of veterans with migraines have comorbidities that confound treatment.
This study suggests migraine management may be better optimized through screening of individuals with conditions that are highly comorbid with migraine—namely TBI, PTSD, epilepsy, stroke, and depression. However, the majority of veterans with migraines do not have these comorbidities, and primary care providers should be more vigilant with headache screening. Furthermore, while further research is required, perhaps more accurate diagnosis of migraine, as opposed to Headache NOS, may lead to more appropriate migraine management.
Clinical implications
There is an increased recognition of migraines in the veteran population. Veterans are generally given guideline-concordant care. Much of the gap in care may be due to veterans who are labeled as Headache Unspecified or other non-migrainous conditions.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study was supported by grants from the VHA Health Services Research & Development Service; IIR 12-118 and CIN 13-047.