Medical Consultation for Migraine: Results From the American Migraine Study

Medical Consultation for Migraine: Results From the American Migraine Study

Richard B. Lipton, MD; Walter F. Stewart, MPH, PhD; David Simon, MS

~ground.-Migraine headaches are often disabling But usually responsive to treatment. Nonetheless, many people with migraine never consult a ductor for heada&as. In a sample of the US population, we sought to determine the proportion of active migaineurs who ever cunsulted a doctor for headache and to identify the headache characteristiu and sociodemographii factors associated with consulting.

Method.-A mailed questionnaire survey was sent to 15060 US households, selected from a panel to be representative of the US population. Of 20 468 eligible respondents ranging in age from 12 to 86 years, 2479 met a case definition for migraine. We mailed a secund questionnaire to all migraineurs identified on the first survey and achieved a 69.4% response rate. The sacond survey m headache characterbtics, patterns of medial care use, madbtion use, and method of payment for health care.

Resutta-Sixty-eight percant of female and 57% of male migrainaurs reported having ever consulted a doctor for headache. Consultatiar~ was more likely with increasing age and in women who ever married. In fernalas, sevaral headache characteristics including pain intansity, number of migraine symptoms, attack duration, and disability were associated with consultation. of those who n- consult, 61% report severe or very severe pain and 67% report savere dii- ability or the need for bed rest with their headaches.

Conclusion.-The results of this urvey indicate that a significant proportion of migraine suffarers never consult daators far their head&res. Given that a large proportion of parsons who newa consult report high levels of pain and disability, these data suggest that thare are opportunitias to appropriately increase heahh care utilization for migraine. Given that 46% of migraineurr who have ever consulted do not report a physician diagnosis of migraine, there is a need to improve headache diagnusis and/or doctor-patient communication abut migraine.

Key wards: migraine, consult, questionnaire

Abbreviations: HDHCCl Headache Disability and Health Care Questionnaire

(Headache 1998;38:87-96)

From the Departments of Neurology, Epidemiology, and Social Medicine, Albart Einstein CoKaga of Medicine, Haad- ache Unit MonWiore Medical Canter, Bronx, NY 6Yrs. Lipton and Stewart); Epidemiology, Johns Hapkii School of Public Health (Mr. Simon); and Innovative Medical Research (Drs. Lipton and Stewart).

Address all correspondence to Dr. Richard B. Lipton, De- partment of Neurology, Muntefiure Medical Centter, 111 East 210th street# Bronw. NY 10467.

-tad for publication June 27,1997.

HEADACHE

Though migraine is a highly prevalent, often painful, and frequently disabling disorder, reasons for seeking and not seeking medical care are not well understood.” Although headaches are a major reason for outpatient medical visits,’ in the United States 71% of men and 59% of women with migraine report that they have never been medically diagnosed with migraine.‘* Of people with undiagnosed migraine, 25% report severe disability or the need for bed rest with their headaches and over 90% report at least some headache-related disability.‘* These findings suggest that undiagnosed migraine is a significant public health problem.‘**” Because there are effective treatments for migraine, many people with undiagnosed disabling migraine might benefit from medical care?”

There are several possible barriers to the effective diagnosis and treatment of migraine.28’o’” Some individuals who would benefit from treatment for migraine may not consult doctors about their headaches. Others may consult without receiving a specific diagnosis; still others may receive an accurate diagnosis without getting effective treatment.” Recent efforts have focused on defining the individuals with migraine most in need of medical care.11’13 To understand the con- tribution of various barriers to care, we evaluated the patterns of consultation and diagnosis in a population-based sample of migraine sufferers. Population-based studies are required to address these issues so that people with migraine are identified whether or not they seek medical care.”

The present study is based on a large sample of migraine sufferers identified in an epidemiologic sun/ey (the American Migraine Study).“” In this article, we examine the patterns of medical consultation, and the predictors of who consults doctors for headache among migraineurs. By comparing the sociodemographic profiles of migraineurs who do and do not consult doctors, we can examine the influence of age, gender, race, income, and insurance status on utilization of medical care for headaches. By assessing pain intensity, attack frequency and duration, as well as associated features (nausea, photophobia, etc)

PAGE 87

we can identify the headache characteristics which motivate migraine sufferers to seek care for headache. Analyzing patterns of consultation and health care delivery for people with migraine is a prelude to designing health care intetven- tions to improve diagnosis and treatment.21213

METHODS

Detailed information on headache history and medical care behavior was obtained using a two-stage survey of individuals participating in the American Migraine Study. The first survey is described in detail elsewhere.’ In brief, a self-ad- ministered questionnaire was mailed to a sample of 15 000 US households selected to be representative of the US population. Responses were obtained from 20468 individuals ranging in age from 12 to 80 years residing in 9507 households for an overall participation rate of 63%. Respondents answered questions about headache symptoms, attack frequency and duration, as well as associated disability. They indicated whether their migraine headaches had ever been diagnosed by a doctor, and whether they used over-the- counter or prescription drugs for headache.““‘*”

Using data from the first survey and operational criteria based on those developed by the International Headache Society (IHS),” 2479 individuals were designated as having one or more migraine headaches in the preceding year. A second questionnaire, (the Headache Disability and Health Care Questionnaire [HDHCQ]) was sent to all of these individuals. Among other factors, the HDHCQ obtained data on headache severity, attack frequency, disability from headache, number of different types of headaches, patterns of medical care use for headache, medication use, and methods of payment for medical care.

Subjects were defined as having ever consulted a doctor for their headaches (ie, ever consulters) if they had ever seen a doctor specifically for headache. Othennrise migraineurs were defined as having never consulted a doctor for their migraine headaches (ie, never consulters). Based on prior work, among migraineurs reporting more than one type of headache, we assumed that the migraine headache was the most severe type.”

Data were analyzed to determine if sociodemographic factors, headache features, or medical care reimbursement status were associated with consultation status (ever versus never) for migraine headache. Sociodemographic factors included sex; race (white versus other); age at interview (~20, 20 to 29, 30 to 39, 40 to 49, 56 to 59, 66+ years); education (<12 years, high school, some post high school, college degree, or more); marital status (never married, ever married, other); household income (~$10,000, >$lO,OOO, >$20,000, >$30,000, >$45,000+); and urban/rural living (population <50,000, >50,000, >500,000+). Data on symptoms associated with migraine (nausea, vomiting, unilateral head pain, pul- sating/throbbing pain, photophobia, phonophobia, visual aura, and sensory aura), were obtained from the first survey and examined as dichotomous variables (yes versus no). In addition, the total number of symptoms associated with migraine was assessed using a scale which added one point for each of the eight symptoms above. Thus, the number of migraine symptoms ranged from zero to eight. Information was also obtained during the first survey on disability (none, a mild/moderate impairment, severe impairment, or the need for complete bed rest); frequency of attacks (2 to 6 times per week, once per week, 1 to 3 per month, 1 to 12 per year); and physician diagnosis of migraine.

These same headache features were assessed during the second survey in relation to the most severe type of headache. In contrast to the categorical response options for attack frequency in the first survey, the second survey included a number of open-ended questions. We defined five fre-

quency categories based on number of attacks per year (0,l to 12, 13 to 36,37 to 52, 52+). During the second survey, pain intensity was rated on a severity scale from 1 to 9; the scale was anchored by “a little painful” at the low end, “moder- ately painful” in the middle, and “the most severe pain I have ever experienced” at the high end. In preliminary analyses, pain intensity was categorized as none, mild (<5), moderate (5 to 6), severe (7 to 81, and very severe (9). Attack duration of the most severe type of headache and data on physician or self-diagnosis of migraine were also assessed. Medical reimbursement status was defined from the second survey by asking respondents, “How is all or most of your medical care paid for?” One of the following options was selected: public insurance (Medicare or Medicaid); commercial insurance (Blue Cross-Blue Shield, Metropolitan Life, etc); prepaid health plan (HMO [health maintenance organization]); self- paid (self or family); other; and don’t know.

To examine the association between consultation status and predictor variables we first describe univariate distribu- tions by consultation status (ever versus never). Crude prevalence ratios were derived as the ratio of the proportion of ever consulters in each category of a variable to that of a reference category (eg, the higher pain intensity group versus the lower pain intensity group). Because preliminary analysis showed that the associations differed for males and females, gender-specific analyses are presented. A chi-squared test was used to identify statistically significant associations between consultation status (ever versus never) and predictor variables.17

Because a number of variables were related to each other and to consultation status, we used Poisson regression to estimate prevalence ratios and to adjust for potential con- founding in a series of models developed for females and males separately. The point estimates from the Poisson model are unbiased even for outcome variables which are very frequent (ie, ever consulted); however, the confidence intervals and significance tests are biased for frequent outcomes. We, therefore, conducted parallel analyses using logistic regression models to test the significance of each covariate. Using logistic regression, the significance tests are unbiased but the odds ratios considerably overestimate the prevalence ratios. We, therefore, report adjusted prevalence ratios using Poisson regression but significance tests from logistic regression. To test for effect modification by gender, a final set of logistic regression models were fitted using data from both males and females combined. Effect modification was tested for by modelling interaction terms between gender and each level of the covariate of interest. Among the sociodemographic variables, age and marital status exhibited statistically significant relationships with consultation status and were, therefore, included in the statistical models as potential confounders.

Variable reduction was required to complete the regression analyses. Variables were defined as follows in the regression models: age (age and age squared); household income (#O,OOO, 830,000 per year or greater); education (ccollege degree, college degree or greater); marital status (never married, currently married versus separated, divorced, or wid- owed); medical reimbursement (Medicaid/Medicare, commercial insurance, prepaid health plan, self-paid, other}; number of symptoms (~5, 5 or greater); disability (none, mild, moderate versus severe, bed rest); pain intensity (~7, 7 or greater); frequency of attacks (~12 per year, 12 per year or greater); and duration of attacks (~24 hours, 24 hours or greater). These cutpoints were devised after reviewing univariate results of the complete set of categories available on each variable without information about relation to consultation status.

In the regression analyses, a likelihood ratio test was used to determine whether a single variable (eg, pain intensity) significantly improved the fit of the model to the data. The degrees of freedom for testing each variable in the model

PAGE 88 FEBRUARY, 1998

were equal to the number of categories for the variable mi- nus 1. Adjusted odds ratios and 95% confidence intervals were computed, reflecting the strength of association between each variable and ever consulting a doctor for headache, after adjusting for covariates.

RESULTS

A total of 69.4% of migraineurs participating in the first survey responded to the second survey (HDHCQ). Respondents and nonrespondents to the HDHCQ did not differ by race, household income, urban versus rural living, nor headache frequency (Table 1). There were significant differences, however, on a number of variables measured during the first survey. Compared to nonrespondents, respondents were more likely to be female, older, and more disabled by their

Table 1 .-Distribution of Eligible American Migraine Study Respondents and Nonrespondents to a

Second Survey (Headache Disability and Health Care Questionnaire [HDHCQ]) by Soclodemographic

and Headache Variables

Variable

% of % of Non- Respondents respondents ’

(n=1720) (n=759) P

Sex Male Female

Race

Ez: A!;oat interview, y

20-29 30-39 40-49 50-59 60+

H;,$$d income

>$l b,OOO >$20,000 >$30,000 >$45,000+

U<~or&;~l living

>50:000 >5oq,,ooo

Disabrlr from x headac e

None Mild/moderate Severe Bed rest

Frequency of headache

1-12/year l -3/month l/week 2-6/week

Medical diagnosis of migraine

Yes No

19.9 31 .o 80.1 69.0

95.5 4.5

1::: 30.6 21.7 15.1 14.1

17.2 19.4 17.9 19.9 25.7

30.8 33.1 20.0 19.9 49.2 47.0

10.3’ 39.0 11.7 36.8

43.02 32.7 10.7 12.9

42.4 28.2 57.6 71.8

95.1 4.9

12.1 18.5 30.4 18.2

9.6 11.2

19.5 18.8 16.5 22.0 23.2

1 5.73 40.1

309::

40.3’ 33.6

1:::

co.01

0.71

<O.OOl

0.32

0.49

<a001

0.13

<O.OOl

headaches. They were also more likely to report a physician diagnosis of migraine. To determine if this response bias influenced the relation between consultation for migraine and covariates, we examined data from the first survey by response status to the second surrey. Because we did not have data on consultation status for the nonresponders, we used reported physician- diagnosed migraine as a proxy for consultation status. Table 2 reveals that there were no differences between respondents and nonrespondents to the second survey in the association between physician diagnosis of migraine and other variables measured during the first survey (ie, sociodemographic variables, headache feature, etc). In the “Comments” section, we consider these results, their limitations, and the possible effects of response bias on inferences regarding the association between medical consultation status and the covariates discussed below.

Predictors of Ever Consulting.-Table 3 sum- marizes the sociodemographic characteristics of subjects with migraine who ever and never consulted a doctor for severe headache. Overall, consultation rates for headache were significantly higher in females (68%) than in males (57%). Consultation was more likely with increasing age in both females and males. Neither race nor income had significant effects on consultation. Though statistically significant differences were identified for education among females, there were no clear patterns to the results. Females, but not males, who were currently or previously married were more likely to consult for migraine. Medical reimbursement status showed a modest effect in females, but not males; recipients of Medicaid and Medicare were the groups most likely to ever consult. Living situation was not associated with consultation status. Urban/rural residence was not associated with consultation status in females, but was in males; unless living in midsize regions (population 50 000 to 500 000) males were less likely to consult.

In univariate analyses, several headache characteristics were associated with medical consultation for headache (Table 4). When assessed individually, virtually every migraine-related symptom (ie, nausea, unilateral pain, photophobia), with the exceptions of throbbing pain and unilateral pain, were more common among females who had ever consulted. Nonetheless, nausea, vomiting, blurry vision, visual aura, and sensory aura were the features most strongly associated with consultation ever in females. Among males, only nausea and vomiting were associated with consultation to a statistically significant degree, though similar trends occurred for the aura features.

.

HEADACHE PAGE 89

Table 2.-Distribution of Migraine Headache Sufferers by Reported Physician Diagnosis of Migraine, Response Status to the Second Survety, and by Headache-Related Variables

Variable

Respondents Nonrespondents Physician-Diagnosed Migraine Physician-Diagnosed Migraine

Yes (“XI) No (“A) PR’ 95% Cl” Yes (%) No (%) PR’ 95% Cl”

N”;:f sympt- Fr&ency of headache

l-W/year >12/year

Disability Not severe Severe/bed rest

ZkA

z:

35.7 64.3

g;

41.4 58.6

61.0 39.0

Females

::: 1.57-1.95

1.00 988 .901-l .08

1:: 1.48-l .84

30.5 67.1 69.5 32.9 ;?I 1.76-2.54

36.6 1.00 61.4 ZI: 959 0.83-l .l 1

40.6 59.4 2: 1:: 1.42-2.10

N”i:f sympt-

Frgency of headache 1-Wyear >12/year

Disability Not severe Severe/bed rest

Males

;I 44.7

1.75-2.96 553 2: ::ZZ 1.42-2.90

1.00 1.00 .754 .589-963 z; 2: 642 0.42-0.98

::z 1 m-2.19 z! Z? ::: 1.46-2.66

l PR indicates prevalence ratio. l *95% Cl indicates 95% confidence interval.

Table 5 examines the effects of the number of migraine symptoms, pain intensity, attack frequency and duration, as well as disability on consultation status. Consultation was more likely as the total number of migraine symptoms increased in females but not in males. Consultation was more prevalent in the groups with the high- est levels of pain, both for females and males; the chi-square test was significant in females but not males; the trend test was highly significant in males (EO.02, not shown in Table 5). Consulta- tion was more likely in groups with very frequent attacks, though results were not statistically significant. As attack duration increased, consultation became more likely, especially in females. The most disabled groups also had a higher prevalence of consultation.

Because many headache characteristics are correlated, we used Poisson regression analysis to estimate the effect of individual headache characteristics after adjusting for the effects of other headache characteristics. As discussed in the “Methods” section, we dichotomized most candidate predictor variables. After adjusting for other covariates, in females, ever consulting was associated with pain intensity, number of migraine symptoms, attack frequency and duration, as well as disability (Table 6). In addition, marital

status was a significant predictor of ever consulting. For males, none of the variables reached statistical significance, though the prevalence ratio estimates for the effects of pain intensity, attack duration, and disability were in the same direction as the results for females. The sample size was smaller for males and the results were close to statistical significance for several variables. Interaction terms for all pairwise combina- tions of age, pain intensity, disability, and attack duration were not significant in either males or fern&s.

To determine if the relationship between consultation status and other covariates differed by gender (ie, if gender was an effect modifier), we combined data on both males and females in a series of models (not shown). Age was modeled as having linear and quadratic terms while all other main effect covariates were defined as bi- nary. We then tested the significance of each covariate’s interaction with gender, in separate models. None of the interaction terms (for gender and headache characteristics) were statistically significant, though the terms for gender and number of associated symptoms (OR=l.71, 95% Cl 0.97 to 3.00) as well as gender and pain (OR=1.55; 95% Cl 0.82 to 2.92) showed a trend towards significance.


Table 3.-Distribution of Migraine Headache Sufferers by Consultation Status (Ever Versus Never) and Sociodemographic Characteristics

Variable No. of IHS

Cases

Females Males

Ever Consutted a Physician Ever Consulted a Physician

Crude No. of IHS Crude No. (%) PR’ P(Y) Cases No. (“YD) PR’ p (x2)

Ay$t interview, y

30-39 4049 so-59

RZ White Other

Marital status Never married Currentty married Sep/div/widow

Income

s;%%

g$z +&OO+

Educatton cl 2 years High school raduate

&I mecoll e./ technical ZIool College degree+ Other

Medical reimbursement St&US**

Self-paid Medicaid/ Medicare Commercial insurance Prepaid heatth Plan l ther

Lrxituation

With relative with nonrelative Other

Urban/rural <50,000 >50,000 >500,000

zi 300 212 197

1316 59

g 309

ZI

2 348

g

449

348 40

216 166

321 (73.0)

425 (682)

152 (65.0)

90 (75.0)

134 68.4 654 34

Ii 68.3 642

110 70.5

!iz 1.X)

!:Z

kg

:g 1.35

k%

:z 1:05

:::

1.12

0.96 1.19

1Izz

1.10

1.04

1.26

:*g O&4 1.03

:z 1:03

~~ 1:18

-01

:::

C.001

024

.OOl

0.52

.02

.02

0.66

0.72

0.45

0.71

0.71

314 7

:tE 1116

19 63.3

29 33 I 50.9 I 56.9

0.13

95 59 (62.1) 1.00

123 10

76(55.5)

42(60.9)

0.42

68

31

2riz 19 7

z 184

‘PR indicates prevalence ratio. **Seventy-three respondents checked more than one response; 54 repotted public assistance and one other form of payment which was cate females did not !zo

nzed as public assistance; 17 females failed to indicate medical reimbursement status and 9 males and 4 w their type of medical reimbursement. Ten females failed lo k&ate race, 11 females did not indicate

marital status, and 2 mates and 23 females did not indicate living situation.

Type of Physician Consulted.-Among migraineurs who ever consulted for headache, the

often general practitioners or family practitioners

majority initially consulted in primary care set- followed by neurologists and a combined group

tings. The providers initially consulted were most of internists or pediatricians (Table 7). Ophthal- mologists, emergency physicians, and gynecolo-

HEADACHE PAGE 91

Table 4.-Distribution of Migraine Headache Sufferers by Gender, Consultation Status (Ever Versus Never), and Proportion Reporting Migraine-Related Symptoms

Variabfe No. of IHS

Cases

Females

Ever Consulted a Physician

Crude No. (%) PR’ P (X2)

No. of IHS Cases

Males


Crude No. (%) PR’ p (x2)

Nausea Yes

No

Ur$teral pain No

biting pain

Yes No

Yes No

Bl+kv vision No

Visual aura Yes No

?zow aura No

997 <.601 204 905 388 117

;.g .

397 COO1 2z

50 988 134 t 53.2)

72.5) ::z

804

z 69

:z .12

11% 94 276 .xI 249 45

1025 x106 211 .02 360 110

1013 .006 202 0.s 68 372 119 1.00

557 991 828 :z

1.13 22 1.00

440 .oOl 110 1.18 .lO 945 211 1.60

1Zl .oOl

2z 99

:z

l PR indicates prevalence ratio.

gists were the providers for a significant minority of patients. Only 1.6% of females and 4.7% of male consulters with migraine were first diagnosed by headache or pain specialists. Overall patterns were similar when the distribution of providers most frequently consulted was examined (data not shown). Of migraineurs who ever consulted for headache, 65.7% of females and 57.9% of males reported that they received a medical diagnosis of migraine. A small proportion of subjects (almost 6% of females and 3.6% of males) reported a medical diagnosis of migraine without consulting specifically for headache. Presumably, these were medical diagnoses made during medical visits for other purposes. Not surprisingly, consultation status and medical diagnosis were strongly associated.

year-olds in the United States, only 15% of males and 28% of females with headache ever consulted a physician for headaches?’ The older age distribution in the present study, along with increasing consultation rates with advancing age, may help explain the higher consultation rates reported herein. The proportion of migraineurs who ever consulted for headache was 81% in a Canadian study? 66% in a British study,*’ and 56% in a Danish study.* The present findings are similar to prevjous population-based repotis suggesting that in many Western countries a substantial proportion of migraineurs never consult doctors for headache.*

COMMENTS

Approximately 66% of migraine sufferers in this study ever consulted a doctor for headache. Several other studies have examined consultation rates for migraine?= In a study of 12- to 29-

Several sociodemographic features were associated with medical consultation for migraine. Consultation ever was more likely in females (68%) than in males (57%). Diagnosis was also more likely in females (66%) who consulted than in males (58%) who consulted. The findings are consistent with other studies which show that women are more likely to consult doctors than men for headache’“” and for a variety of other conditions.*=


Table S.-Distribution of Migraine Headache Sufferers by Gender, Consultation Status (Ever Versus Never), and Proportion Reporting Migraine-Related Features

Females Males

Variable


Crude No. (“X,) PR’ P (x2)

No. of IHS cases


Crud8 No. (“%B) PR’ P (x2)

Total No. of symptoms

z 5+

Pain intensity from most severe

None/mild (~5) Moderate (5-6) Severe (7-6) Very severe (9)

Frequency of most severe attacks in

tYitzzar l-11 12-36 37-52

DzLonofmost severe headache, h

&4 25-46 49+

Disability from most severe

bKz?s Mild/moderate Sever8 Bed rest

4 695

486 666 114 64

35

z 712

36 50.7 596 197

PI 66.0 4.3

37 75.5 57 70.1

&Ol r)

:g

401 28

1Z 80

<.OOl $ 43

::

<.OOl 151 137 15 5

401 11

ii 140 91 (65.0)

34

.12

56

63

.07

l PR indicates prevalence ratio. Two mates and 18 females failed to indicate disability; 6 males and 24 females did not indicate frequency; and 13 mates and 55 females did not indicate duration.

Table 6.-Poisson Regression Models Predicting Ever Versus Never Consulting for Headache in Females and in Males With Migraine*

Females

Prevalence Ratio P

Males

Prevalence Ratio P

Pain No. of symptoms ;~$f$~eg~

Disability Currently married Previously married

<.OOl 124 :z <.OOl 1.14 <.OOl :z 1.14

z2 1:19

1.09 1.16 1.18 92 1 .Ol 1.17 95 1.09

“Significance of the prevalence ratio was tested using logistic r8gression (see text).

HEADACHE

Table 7.-Distribution of Migraine Headache Sufferers Who Ever Consulted for Headache By the Type of Provider Consulted Initially and Most Frequently

Distribution of Initial Providers* Distribution of Most Frequent Providers”

Females (n=619)

Males (n=106)

Females (n=235)

Males (n=39)

General/family practitioner Neural ist

7 lntemis pediatrician Obstetrician@ynecologist Ophthalmol Ist

“31 Emergency p ysician Pain/headache specialist Other

46.4 13.6 11.5 42 3.6 3.4

1:;

48.1 43.0 10.4 12.3 14.1 14.9

-

::: ; .

1:: 2z

36.5 10.3 15.4

::

:; ti8

*Health care professional who first diagnosed the sub’ect’s most severe type of headache. **Health care professional most frequently consulted I or headache.

Consultation was also more likely with increasing age, particularly above age 50, both in women and men. Since migraine is a condition of early onset,27’p increased rates of consultation in older age groups may reflect a longer duration of illness and, therefore, increased opportunities for consultation. In addition, health care use in- creases with age for a range of disorders, per- haps contributing to the present findings.as The significance of headache also changes with advancing age as brain tumors, temporal arteritis, and other very serious conditions become more likely3’ and as new-onset primary headache disorders become less likely.n’28 Awareness of these changing etiologic profiles on the part of physicians or patients may influence rates of consultation.

Marital status was a significant predictor of consultation ever in women but not in men. Women who were currently or previously married were about 30% more likely than those who never married to consult a doctor for headache. This result remained significant after adjusting for all of the headache characteristics we measured. This propensity to consult may be a consequence of psychosocial factors associated with marrying; alternatively, interactions within the marriage may encourage women to consult.

Using the self-paid group as the reference, migraineurs whose health care was covered by Medicaid/Medicare, commercial insurance, or prepaid health plan were somewhat more likely to have ever consulted a doctor for headache in univariate analyses. However, no difference was observed after adjusting for other factors.

Headache characteristics were associated with consultation status in both males and females. The strong association with pain intensity parallels patient reports that pain is the most disturb ing aspect of migraine and that pain relief is their

most important goal in seeking care? Other headache characteristics including number of migraine symptoms, attack frequency, attack duration, and disability were all independent predictors of consultation in females in a multivari- ate model. Prior work has demonstrated that disability is strongly associated with both pain intensity and number of migrainous features.7 In males, nausea and vomiting were the symptom features most strongly associated with consultation, though other factors were not statistically significant. Attack duration was a statistically significant predictor and trends were also present for pain intensity and disability. In a multi- variate model, none of these factors reached statistical significance.

The gender differences in the relationship between headache characteristics and consulting behavior were striking. A number of headache characteristics were associated with consulting behavior in women but not in men. One possible explanation is that in women consulting, behavior is determined by their headache characteristics, while men are less likely to consult, even when they have a severe symptom profile. In regression analysis which included both men and women, we examined this hypothesis by including interaction terms in the model for gender and headache characteristics. While these interaction terms were not statistically significant (after adjusting for other covariates), the trends are sug- gestive; even at high levels of pain, the odds of consulting are 1.55 higher in women than in men.

Many indices of headache severity (eg, pain intensity, attack frequency, and number of associated features) are associated with consultation status, suggesting that the people most in need of medical care are more likely to seek it. But many people with severe or very severe head-


aches never seek care; among females who never consulted, 60% report severe or very severe pain while 68% report severe disability or the need for bed rest. Thus, many people who never see a doctor have severe headaches and might benefit from improvements in treatment. For the nonconsulters with mild or moderate pain and little disability, self-care is an appropri- ate option.

Additionally, many people with migraine who consult for headache never receive a specific medical diagnosis. In this study, 56% of migraine sufferers reported that they never received a medical diagnosis of migraine. Of these individuals with undiagnosed migraine, 58% never consulted for headache, but 42% consulted without receiving a diagnosis, at least not one that the subject could report. In some cases, physicians may fail to make a specific diagnosis or may fail to effectively communicate it to the patient.” In addition, patients who have been cor- rectly diagnosed may fail to recall or report the diagnosis.” To resolve these issues, systematic review of medical records is required to circum- vent the limitations of patient recall.

In the Olmsted County migraine incidence study, linked medical records were used to identify people with medically diagnosed migraine? In that study, 15% of an inception cohort of migraineurs were initially assigned diagnoses other than migraine (ie, tension-type headache or headaches not otherwise specified). Stang and von Korff recently reported that in a health maintenance organization, only 45% of patients with migraine who consulted their doctors for headache received an accurate medical diagnosis? This report parallels the present findings in a population-based sample. Clinical features such as female gender, the presence of aura, headache-related disability, and the absence of comorbid depression increased the likelihood of accurate medical diagnosis of migraine.‘0*20$2

Of those migraine sufferers who consult, the majority initially consult in primary care settings (general practice, internal medicine, and pediatric settings). A significant minority consult neurologists, ophthalmologists, emergency physicians, and gynecologists. Similar patterns of consultation by medical specialty have been reported elsewhere? The higher proportion of neurologic consultations in the present study may reflect the older age distribution of our study sample. These findings suggest that health care intervention intended to improve the diagnosis and treatment of migraine should be directed to primary care settings where the majority of patients consult.

This study has a number of limitations, some of which are inherent to survey research. It is possible that our IHS-based diagnoses may be

over inclusive, mistakenly assigning people who do not have migraine to the migraine group?” This is unlikely to be a major factor for several reasons. The migraine case definition used herein is relatively restrictive in comparison with criteria recommended for clinical diagnosis in the primary care setting? In addition, the prevalence of migraine and its distribution by age and sex closely resemble other studies,6 including one which relied on diagnoses assigned using IHS criteria as assessed by a neurologist.’ Disability profiles for migraine are similar to other reports.2*7 If there were high rates of misclassifica- tion (overdiagnosis using our survey), we would expect the age, sex, and disability profiles to shift. In addition, the present results are compa- rable with other similar studies and with research which relies on medical record review.2’20’n3 Other issues pertaining to our symptom-based diagnoses have been discussed elsewhere.3”0

Selection bias introduced by nonparticipation in the second survey is a potential limitation. In particular, respondents who reported a physician diagnosis of migraine were more likely to re- spond to the second survey. As a consequence, in the second survey we may overestimate the proportion of migraineurs who have ever consulted and also the proportion with very severe headaches. Using data on physician diagnosis from the first survey as surrogate for consultation status, we found that the proportion of ever consulters in the second survey is overestimated by a factor of 0.12 relative to the original survey. Similarly, the proportion of migraineurs with severe headache is overestimated by a factor of 0.06 in the second survey. These effects intro- duce only modest errors in our point estimates. If there was selection bias with regard to both consultation status and headache severity, we may have overestimated the association between these variables. We used data from the first survey and physician diagnosis as a surrogate for consultation to assess the effects of referral bias (Table 2). We found no significant differences by response status in the odds ratios between physician diagnosis and specific symptoms (data not shown), number of symptoms, frequency of attacks, or disability. Assuming that reported physician diagnosis is a reasonable surrogate for consultation status, we conclude that the selection bias inherent to the second survey does not have a meaningful effect on measured associations between consultation status and predictor variables.

Finally, we evaluated the relationship between current headache characteristics and consultation status. If consultation leads to health care interventions which help control headaches, the benefits of care may alter the measured associa-

HEADACHE PAGE 95

tions between headache characteristics and consultation. This difficulty could be circumvented by studying incident consulters and nonconsult- ing controls in a closed health care system.

Based on these findings, we conclude that lack of consultation and lack of diagnosis among consulters contribute to the low rates of medical diagnosis of migraine. Consultation and diagnosis are less likely in men, in the young, and in people who pay for their own health care, suggesting that certain sociodemographic profiles impose barriers to care. While people with high impact migraine are more likely to consult, many nonconsulters experience high levels of pain and disability. Intementions should be devised to improve outcomes in the nonconsulters with substantial pain and disability.

Acknowledgments: This work was supported in part by a grant from GlaxoWelicome. Apprecia- tion is expressed to Toni Guglielmo for her assistance in the preparation of this manuscript.

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REFERENCES

Rasmussen BK, Jensen R, Schroll M, Olesen J. Epide- miology of headache in a general population-a prevalence study. J Clin Epidemioi. 1991;4411147-1157. Rasmussen BK, Jensen R, Olesen J. Impact of headache on sickness absence and utilisation of medical services: a Danish population study. J Epidemior Community Health. 1992;46:443-446. Stewart WF, Lipton RB, Celentano DD, Reed ML. Preva- lence of migraine headache in the United States. Rela- tion to age, income, race, and other sociodemographic factors. JAMA. 1992;267:64-69. Breslau N, Davis GC, Andreski P. Migraine, psychiatric disorders, and suicide attempts: an epidemiologic study of young adults. Psychiatry Res. 1991;37:11-23. Henry P, Michel P, Brochet B, Dartigues JF, Tison S, Salamon R. A nationwide survey of migraine in France: prevalence and clinical features in adults. Cephalalgia. 1992; 12:229-237. Stewart WF, Simon D, Shechter A, Lipton RB. Population variation in migraine prevalence: a meta-analysis. J C/in Epidemiol. 1995;48:269-280. Stewart WF, Shechter A, Lipton RB. Migraine heteroge- neity. Disability, pain intensity, and attack frequency and duration. Neurology. 1994;44(suppl 4):S24-S39. Stang PE, Osterhaus JT, Celentano DD. Migraine. Pat- terns of healthcare use. Neurology. 1994;44(suppl 4):S47-s55. National Center for Health Statistics. Acute Conditions: Incidence and Associated Disability, United States. Rockville, Md: National Center for Health Statistics, Vital and Health Statistics, National Health Survey series 10, No. 77; 1972. US Dept of Health, Education, and Welfare publication 73-1503. Lipton RB, Stewart WF, Celentano DO, Reed ML. Undi- agnosed migraine headaches. A comparison of symptom-based and reported physician diagnosis. Arch Int Med. 1992;152:1273-1278. Lipton RB, Amatniek JC, Ferrari MD, Gross M. Migraine. Identifying and removing 1994;44(suppl4):%3-s68.

barriers to care. Neurology.

12.

13.

14.

15.

16. 17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

Olesen J, Tfelt-Hansen P, Welch KMA. The Headaches. New York, NY: Raven Press; 1993:229405. Von Korff M, Stewart WF, Lipton RB. Assessing headache severity. New directions. Neurology. 1994;44(suppl 4):S40-s46. Celentano DD, Stewart WF, Lipton RB, Reed ML. Medica- tion use and disability among migraineurs: a national probability sample survey. Headache. 1992;32:223-228. Headache Classification Committee of the International Headache Society. Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain. Cephalalgia. 1988;8(suppl7):1-96. Stewart WF. Personal Communication. 1994. Fleiss JL. Statistical Methods for Rates and Proportions. New York, NY: John Wiley & Sons; 1981. Linet MS, Stewart WF, Celentano DD, Ziegler D, Spre- cher M. An epidemiologic study of headache among adolescents and young adults. JAMA. 1989;261:2211- 2216. Stewart WF, Celentano DD, Linet MS. Disability, physician consultation, and use of prescription medications in a population-based study of headache. Biomed Pharma- cother. 1989;43:711-718. Edmeads J, Findlay H, Tugwell P, Pryse-Phillips W, Nel- son RF, Murray TJ. Impact of migraine and tension-type headache on life-style, consulting behaviour, and medication use: a Canadian population survey. Can J Neural Sci. 1993;20:131-137. Rawlins E. Epidemiology of migraine. In: Ekbom K, et al, eds. Proceedings of the European Headache Federation. Bremen: European Headache Federation; 1992. Celentano DD, Linet MS, Stewart WF. Gender differences in the experience of headache. Sot Sci Med. 1990;30:1289-1295. Stang PE, Osterhaus JT. Impact of migraine in the United States: data from the National Health Interview Survey. Headache. 1993;33:29-35. Nathanson CA. Sex, illness, and medical care. A review of data, theory, and method. Sot Sci Med. 1977;11:13-25. Verbrugge LM. Sex differences in complaints and diagnoses. J Behav Med. 1980;3:327355. Wilensky GR, Cafferata GL. Women and the use of health services. Am Econ Rev. 1983;73: 128-133. Stewart WF, Linet MS, Celentano DD, Van Natta M, Ziegler D. Age- and sex-specific incidence rates of migraine with and without visual aura. Am J Epidemiol. 1991;134:1111-1120. Stang PE, Yanagihara T, Swanson JW, Beard CM, Mel- ton LJ Ill. A population-based study of migraine headaches in Olmsted County, Minnesota. Case ascertain- ment and classification. Neuroepidemiology. 1991;lO: 297307. U.S. Senate Special Committee on Aging. Aging Amer- ica. 8th ed. Bethesda, Md: US Department of Health and Human Services; 1988. National Center for Health Interview Survey. United States, Vital Health Statistics; 1987:164. Lipton RB, Pfeffer D, Newman LC, Solomon S. Head- aches in the elderly. J Pain Symptom Manage. 1993;8:87-97. Stang PE, Von Korff M. The diagnosis of headache in primary care: factors in the agreement of clinical and standardized diagnoses. Headache. 1994;34: 138-l 42. Solomon S, Lipton RB. Criteria for the diagnosis of migraine in clinical practice. Headache. 1991;31:384-387.


Medical Consultation for Migraine: Results From the American Migraine Study

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