Whenever I read in the paper that “such-and-so costs society $100 gazillion dollars a year”, I am always slightly suspicious. I never know where such figures come from, but I do know that whoever’s quoting them wants you to think that whatever-it-is is a problem. So I was interested to see this recent paper by Dr. Tim Jurgens of University of Regensburg in Germany assessing the degree of economic and non-economic disability in cluster headache. Let’s see how he went about it.
Impairment from headache is more than just the pain of the headache. It has been suggested that there are three main factors that play into it: 1) headache “density” (i.e. the degree of headache activity), 2) affective distress (i.e. emotional response to the headache, usually depression in chronic cases), and 3) disability at work and socially. There are a variety of rating scales that have been devised to measure each of these three categories. Dr. Jurgens used the German version of the Henry Ford Hospital Headache Disability Inventory (HDI), which has two subscales: “Emotion”, measuring the effects of headache on mood, and “Function”, measuring the effects of headache on activities of daily living. He also screened people for psychiatric illness, and asked them whether they had thought about death or experienced suicidal tendencies.
He performed these tests on five groups. The first three had cluster headache: 27 people with chronic cluster headache, 26 people with episodic cluster headache in-period, and 22 people with cluster headache out-of-period. He also tested 24 people with migraine, and 31 healthy controls without headache at all. Patients were recruited from the Departments of Neurology, University Hospitals of Regensberg and Halle and at the Kiel Headache Center, but we’re not told how.
There were more men than women in the cluster headache groups (~4:1 ratio), and more women than men in the migraine group (~4:1 ratio), as expected. 26% of the chronic cluster headache patients had an “invalidity allowance” (a German benefit for the disabled meaning that they cannot work), which was striking in comparison—only 4% of the episodic cluster headache patients who were in-period had such an allowance, and none of the episodic cluster headache patients who were out of period, the migraineurs, or the healthy normals had an invalidity allowance. Dr. Jurgens found that there wasn’t much difference on the HDI between the chronic cluster headache patients and the episodic patients within-period. Disability is shown. Total disability is shown in Table 1, and social disability in Table 2—impact on socialization in black, and family and friends in grey.
What aspects of cluster headache had the most impact on impairment? The older the age of onset, the more the impairment, although age itself was not a factor. Dr. Jurgens speculates that younger patients are able to adapt their lives better to the presence of cluster headache, whereas older patients who are already settled with jobs and family have a harder time. The number of attacks per day (although there was no relation between migraines per month and impairment in the migraine group). Within the chronic cluster headache group, continued attacks despite medication had a negative effect on the “Emotion” subscale, as one might expect. About half the chronic cluster headache patients experienced depressive symptoms, compared with only a fifth of the healthy control group. 22% had thought about killing themselves, compared with only 15%of the episodic cluster headache group. This actually seems a little low to me. Interestingly, even episodic cluster headache patients who were not experiencing attacks still had a high disability score even though they were not in pain. Why this is isn’t clear. Obviously, repercussions of having cluster headache persist beyond the period of actual attacks.
Although most patients with cluster headache are men, impact on women can be severe also. Dr. Ekbom showed 30 years ago that women with cluster headache end up having fewer children, and five years ago Dr. van Vliet reported that of women with cluster headache who had no children, a third said that it was because of their cluster attacks. 40% of cluster headache patients were convinced that their headache had limited their career, and only 38% reported no reduction in work efficiency. 16% lost their jobs; 8% had to retire early. Chronic cluster headache patients were especially limited in their career choices. Dr. Jurgen’s didn’t collect any data on cluster headache-related healthcare costs in these patients.
This was a well-done study. Although there are eight other studies in the last fifteen years that have assessed life impairment from cluster headache, this was the first to compare cluster headache with migraine and healthy controls, and also subdivide the cluster headache group into chronic and episodic both in and out of period. What it showed was a massive impact of cluster headache—especially the chronic form, and the episodic form while in an active period—in various economic and non-economic areas.