Headache Prevalence at 4-11 Years After Deployment-Related Traumatic Brain Injury in Veterans of Iraq and Afghanistan Wars and Comparison to Controls: A Matched Case-Controlled Study.

Abstract

Evaluate the extent and severity of headache following deployment-related TBI (D-TBI) in veterans of the Iraq (OIF) and Afghanistan (OEF) wars over a follow-up period of 4-11 years with comparison to age, sex, race, and time of deployment matched controls. TBI has been recognized as the "signature Injury" of the OEF/OIF campaigns occurring in 14-20% of deployed soldiers. Currently, there are very few data on the longer term follow-up of soldiers with D-TBI. This study deals with prevalence and severity of headache and headache burden at 4-11 years following D-TBI for OEF/OIF veterans with comparison to controls without D-TBI. This is a matched case controlled-study. All subjects were recruited from Operation New Dawn (OND), a voluntary program for OEF/OIF Veterans at the Oklahoma VAMC designed to assist with re-integrating into civilian life. On entry into OND a medical questionnaire was administered that included a brief screen for D-TBI, and those with a possible D-TBI were referred to a TBI clinic, For this study, the first 500 TBI clinic patients who were found to have had a D-TBI (TBIS) were matched by age, sex, race, and time of deployment to control subjects (CS), drawn from the 4411 OND program members with no D-TBI, creating a pool of 500 TBIS/CS pairs. From this pool, 55 pairs (11%) were randomly selected for this study. Data were collected from both TBIS and CS by telephone interview with questionnaires regarding the DTBI, headache, depression, and PTSD. TBI severity was measured by duration of loss of consciousness (LOC) as: [a] Very Mild (VMTBI, dazed only, no LOC), [b] Mild (MTBI, LOC 1-30 minutes), and [c] Moderate-Severe (MSTBI, LOC > 30 minutes). Intensity for individual headaches was measured by disability produced by the headache as: [a] Disabling (must be in bed), [b] Severe (50-90% decrease in activity), or [c] Mild-Moderate (>50% of usual activity possible). Statistical analysis employed Fisher's exact test and odds ratio. The 55 TBIS/CS pairs were segregated by severity of TBI for the TBIS. For the TBIS there were no significant differences among these three subgroups as to mechanism producing the TBI (blast injury or direct head trauma). Comparing TBIS vs CS for phenotypic classification of headaches, for TBIS - 89% had migraine, 2% probable migraine, 9% had tension, and 0% had no headaches, while for CS - 36% had migraine, 15% probable migraine, 27% tension, and 22% no headache (P < .0001). Migraine with aura occurred in 38% of TBIS and 6% of CS (P < .0001). As to headache frequency, for TBIS - chronic daily headache (CDH) occurred in 44%, frequent headache in 33%, and infrequent or no headache in 23%, while for CS - CDH occurred in 7%, frequent headache in 13%, and infrequent or no headache in 80% (P < .0001). For TBIS, 54% had severe or disabling headache ≥2 days/week as opposed to only 16% of CS (OR 6.13 [2.5-14.9]). As to onset of most severe and frequent headaches, this occurred shortly after TBI in 89% of TBIS while only 27% of CS reported most severe headaches starting during deployment. There was no correlation of severity of headache problem with severity of TBI. Comparing TBIS at 4-7 vs 8-11 years after injury, there was no difference in frequency or severity of headache between these groups. At 4-11 years after D-TBI for TBIS, or after deployment for CS, the TBIS as compared to CS suffered much more frequent and severe headaches. For TBIS, there was no relation of headache intensity or phenotype to severity or cause of the TBI, and the Headache Burden has not improved over time up to 11 years after D-TBI. The process initiated by the D-TBI that relates to the headache has a prolonged effect up to and beyond 11 years.