Soldiers evacuated from current war zones with a headache diagnosis are unlikely to return to duty, a new retrospective study has found.
Only about a third of these soldiers were able to return to duty, even after receiving treatment, Dr. Steven P. Cohen and his colleagues reported (Cephalalgia 2011 Oct. 12 [doi:10.1177/0333102411422382]).
Headaches account for a significant burden in units and for health care providers deployed to combat zones, wrote Dr. Cohen of both Johns Hopkins University, Baltimore, and the Uniformed Services University of the Health Sciences, Bethesda, Md. "The overall [return-to-duty] rate of 33.6% is one of the lowest among all injury types, and to some degree reflects the observation that a large percentage of headaches were incurred during combat operations."
Throughout history, most war casualties haven’t been battle related, Dr. Cohen said in an interview: "Since World War I, nonbattle injuries have been by far the No. 1 reason a soldier is evacuated from the field." Dr. Cohen is a colonel in the U.S. Army Reserve and director of pain research at the Walter Reed National Military Medical Center.
"In the earlier wars, it was respiratory and infectious disease. In these more modern conflicts, the No. 1 reason for evacuation is musculoskeletal injury, followed by psychological and neurological problems – and all of these can involve headache."
"We now know that two-thirds of [soldiers] who leave with headache don’t come back, and even if they do, they may have limitations."
Headache is the most common neurologic symptom in the world, he said, with some studies claiming that up to 70% of people are affected. But recent studies of soldiers deployed in the current wars suggest that the headache burden among recently deployed soldiers may be even larger. In addition to risking a combat injury, young people are exposed to constantly high stress levels. The combination is a perfect recipe for severe headaches.
"There are incredible psychosocial stressors involved in being deployed," he said. "In addition to the daily possibility of being injured or killed, soldiers worry about family separation and about their colleagues who serve along with them. And this is happening in young people in whom sophisticated coping mechanisms have not yet been developed."
To understand how headache might affect the strength and stability of military units, Dr. Cohen and his coauthors reviewed the records of 985 soldiers who had been evacuated from the wars during 2004-2009 with a primary diagnosis of headache.
Headache diagnoses fell into seven categories: postconcussive (33%); tension type (11%); migraine (30%); cervicogenic (9%); occipital neuralgia (5%); cluster (2%), and "other," a category that included tumor, vascular pathology, psychogenic headache, substance abuse, and cerebrovascular events presenting as headache.
The soldiers’ mean age was 30 years; most (88%) were men.
Almost half of the headaches (48%) were related to physical trauma; 3% were deemed psychological or emotional, 3% as environmental or infectious, and the remainder were of other etiologies or unknown. In all, 22% of the soldiers reported a prior history of headache.
Headaches were deemed to be battle related if they were sustained in a combat operation (31%). Another 62% were not related to combat, and data were unavailable for the remainder.
Episodic headache was most common (52%); 39% had constant headache. The authors did not find frequency data for 9% of the group.
Once evacuated, treatment varied widely among the group. NSAIDs were the most commonly used medications (77%), followed by antidepressants (64%), opioids (34%), anticonvulsants (29%), and triptans (27%).
Other medical treatment included beta-blockers (11%) and calcium channel blockers (2%). Many soldiers (36%) were on multiple therapies, and 9% received injections or nerve blocks.
Overall, 33.6% of the soldiers were able to return to duty. In multivariate regression analyses of the factors associated with return to duty, the investigators controlled for age; sex; military branch; headache diagnosis and etiology; treatment; psychiatric and brain injury history; family and personal headache and pain history; and smoking.
Headache type was significantly associated with return to duty. A diagnosis of occipital neuralgia lowered the odds of returning to duty by 80%, compared with tension-type headache, the reference diagnosis. Other diagnoses that lowered the odds of returning to duty included postconcussive headache (by 67%), cervicogenic headache (by 60%), and coexisting traumatic brain injury (by 50%).
"Since World War I, nonbattle injuries have been by far the No. 1 reason a soldier is evacuated from the field."
The method of treatment also affected return to duty. Compared with no treatment, the odds of returning to duty were significantly lowered by 59% with opioids and by 74% with beta-blockers.