Migraine Prevalence and Health Care Usage: Updated Estimates
Updated estimates of the prevalence and burden of migraine in the United States have been summarized in one paper.1 The authors compiled results from four national surveillance studies:
- National Health Interview Survey (NHIS)
- National Ambulatory Medical Care Survey (NAMCS)
- National Hospital Ambulatory Medical Care Survey (NHAMCS)
- Defense Medical Surveillance System (DMSS)
The NHIS collects data from a representative sample of non-institutionalized adults. Information is collected through structured interviews of all available household members. The NAMCS collects information about outpatient visits to office-based physicians. Physicians provide data about symptoms, diagnoses, medication prescriptions, and other treatments over a one-week period. Similarly, the NHAMCS collects information about visits to hospital-based ambulatory care settings, such as emergency departments, hospital outpatient clinics, and ambulatory surgery centers. Information about chief medical complaint, diagnoses, tests and procedures, medications, and patient demographics is collected over a four-week period. The DMSS is a database of medical information for US military personnel. Information about current and previous diagnoses, medical history, and deployments is recorded.
NHIS data showed that 14.1% of US adults had migraine or severe headache in the three months before the survey. Far fewer service members have migraine; estimates from 2010 show that 1.9% have been diagnosed with migraine.
Women are twice as likely to have a migraine as men (18.9% vs 9.0%, per NHIS data). Young and middle-age women seem to be the most affected: More women aged 25 to 44 years seek outpatient medical care for migraine than any other group. Whites were more likely than blacks or Asians to have migraine. The prevalence of migraine was inversely related to income. It was highest among people who were not employed but who had worked previously (20.1%), and lowest among people who were employed full time (11.4%).
Migraine prevalence among the general population was fairly stable between 2005 and 2012. Prevalence peaked in 2010 at 16.6% overall in 2010, and was at its lowest in 2007 at 12.3%. Among service members, migraine prevalence has increased steadily since 1998.
Data from NAMCS showed that headache was the 20th most common reason for outpatient visits in 2009, comprising 1.2% of visits. It was not among the top 20 reasons in 2010. Combined results from NAMCS and NHAMCS showed that 0.5% of ambulatory care visits were due to migraine, and 0.4% were due to headache. More than half of these visits were to primary care offices, about a quarter were to specialty clinics, and over 16% were to the emergency department (ED).
Emergency department visits
There were an estimated 7.7 million ED visits for migraine in 2010. Migraine was the fourth most common reason to visit the ED, behind abdominal pain, chest pain, and fever. It was the patient-reported reason for 3.1% of visits, according to NHAMCS. Given the much higher prevalence of migraine in women, it may not be surprising that it was the third most common reason for ED visits in young and middle-aged women, whereas it was the tenth most common reason in men.
Analgesics were provided, prescribed, or continued more often than any other drug class during office and emergency department visits (for migraine or otherwise) in 2009-2010. They accounted for 10.9% of prescriptions during an office visit, and 34.9% of prescriptions in the emergency department. Use of opioids for headaches treated in the ED increased from 20.6% in 2001 to 35% in 2010. Use of triptans, butalbital combination products, or acetaminophen was stable. More IV fluids and NSAIDs and fewer antiemetics are being used.
The authors concluded that migraine remains highly prevalent. Vulnerable populations—including the uninsured, unemployed, or part-time workers—are disproportionately affected. Patients with migraine use health care frequently. Although most seek medical care from primary care providers, 16.7% are treated in the ED. Migraine treatment in the ED may be suboptimal, as evidenced by the increasing rate of opioid prescribing.
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