Abstract
We read with great interest the recent article by Dr. Cohen and colleagues (1). The authors are to be commended for their contribution toward a greater understanding of headache disorders in service members. In their recent study the authors evaluated a cohort of evacuees from Operations Iraqi and Enduring Freedom for primary headache diagnoses and several factors related to return to duty. Although it was not surprising that the most common primary headache diagnosis in this population was post-concussion headache (34.1%), it is notable that the authors found a migraine prevalence of 30% in their cohort of predominantly male service members (88%). We believe that the high prevalence of migraine in predominantly male service members who are being considered for return to active duty may warrant special consideration.
In a recent general population study of over 5,600 participants, the odds of post-traumatic stress disorder (PTSD) were three- to four-fold greater in men with migraine as compared to women with migraine (2). Available evidence also suggests that life-threatening traumas, such as occur with military combat, are associated with an 8.5-fold increase in PTSD risk compared with other types of trauma (3). Furthermore, almost 25% of migraineurs with PTSD report combat as the most significant traumatic life event associated with their PTSD (4). Thus, the high prevalence of migraine in service members being considered for return to combat, as well as the strong association between migraine and PTSD, underscore the importance of giving serious consideration to enhanced clinical vigilance and aggressive treatment of both disorders in service members (1,2,4).
This raises another point that deserves greater attention from Cohen and colleagues’ recent study. Interestingly, the authors found that the use of beta-blockers was the factor most strongly associated with failure to return to duty (odds ratio (OR) 0.26; 95% confidence interval (CI) 0.12–0.61; p = 0.002), moreso than opioid use (OR 0.41; 95% CI 0.26–0.63; p < 0.001) and even traumatic brain injury (OR 0.50, 95% CI 0.29–0.82; p = 0.01). The authors hypothesized that this may be due to greater disease burden (1). We agree that beta-blocker use may be a risk marker for migraine severity and greater disease burden. In addition, we hypothesize that the coexistence of other migraine comorbidities, such as hypertension and even PTSD, for which beta-blockers may also be utilized, could play a role, (albeit controversial). It is also worthy of note that previous research has found lower heart rate variability in patients with combat-related PTSD (5). Thus, one should consider the possibility that the medical indications for prescribing beta-blockers, or perhaps the medications themselves, could potentially predispose patients to greater vulnerability to PTSD, and consequently contribute to lower rates of return to duty. Regardless of the mechanisms, the authors’ current findings suggest that clinicians treating service members with migraine should, at the very least, consider use of migraine preventives other than beta-blockers (e.g. tricyclic antidepressants, or anti-epileptics such as topirimate and gabapentin), and should perhaps be cautioned against beta-blocker use for migraine prevention pending further clarification.
Further research in regard to the special considerations of headache treatment in service members in general (and in male service members in particular), as well as research to quantify the independent and joint effects of migraine, and migraine treatments (particularly with beta-blockers), on health outcomes in service members, is warranted.