Traumatic Brain Injury Hospitalizations of U.S. Army Soldiers Deployed to Afghanistan and Iraq Barbara E. Wojcik, PhD, Catherine R. Stein, MS, Karen Bagg, MS, Rebecca J. Humphrey, MA, Jason Orosco, BS Background:Traumaticbraininjury(TBI)isalife-alteringconditionthathasaffectedmanyofour soldiersreturningfromwar.Inthecurrentconflicts,theimprovisedexplosivedevice(IED)hasgreatly increasedthepotentialforsoldierstosustainaTBI.Thisstudy’sobjectivewastoestablishbenchmark admissionratesforU.S.ArmysoldierswithTBIsidentifıedduringdeploymenttoIraqandAfghanistan. Methods:ThestudypopulationconsistedofU.S.ArmysoldiersdeployedtoIraqandAfghanistan fromSeptember11,2001,throughSeptember30,2007.Populationdataweremergedwithadmission datatoidentifyhospitalizationsduringdeployment.UsingtheinternationalBarellInjuryDiagnosis Matrix,TBI-relatedadmissionswerecategorizedintoType1(themostsevere),Type2,andType3 (theleastsevere).Allanalyseswereperformedin2008. Results:Ofthe2898identifıedTBIinpatientepisodesofcare,46%wereType1,54%wereType2, andlessthan1%wereType3.Over65%ofType1injuriesresultedfromexplosions,whilealmosthalf ofallTBIswerenon-battle-related.OverallTBIadmissionrateswere24.6forAfghanistanand41.8 for Iraq per 10,000 soldier-years. TBI hospitalization rates rose over time for both campaigns, althoughU.S.ArmysoldiersinIraqexperienced1.7timeshigherratesoveralland2.2timeshigher Type 1 admission rates than soldiers in Afghanistan. The TBI-related proportion of all injury hospitalizationsshowedanascendingtrend. Conclusions:FuturesurveillanceofTBIhospitalizationratesisneededtoevaluatetheeffectiveness ofimplementationofpreventivemeasures. (AmJPrevMed2010;38(1S):S108–S116)PublishedbyElsevierInc.onbehalfofAmericanJournalofPreventive Medicine Introduction Americanscurrentlyhavealong-termneedofdailyassis- tanceduetoTBI.2 T raumaticbraininjury(TBI)isabluntorpenetrat- Similarly, TBI is a major health concern for the U.S. ing injury to the head that disrupts brain func- military,bothincombatandnoncombatsettings.4–9The tion.1,2TheCDCestimatesthatatleast1.4million Armed Forces Health Surveillance Center (AFHSC) re- TBIsoccurintheU.S.eachyear,resultingin1.1million ported that during a 10-year period (January 1997– emergency department visits, 235,000 hospitalizations, December2006),110,392militarymembershadatleast and 50,000 deaths.3 The CDC also estimates that each one TBI-related medical encounter, and there were year between 80,000 to 90,000 Americans experience 15,732hospitalizationswithTBI-relateddiagnoses,with TBIsthatresultinpermanentdisabilities,and5.3million falls/miscellaneous and land transport accidents being themajorcauses.5 FromtheCenterforArmyMedicalDepartmentStrategicStudies(Wojcik, The nature of the current conflicts—in particular the Stein, Bagg, Humphrey), U.S. Army Medical Department Center and School, Fort Sam Houston, Texas; and Lockheed Martin Corporation widespreaduseofimprovisedexplosivedevices(IEDs)— (Orosco),Bethesda,Maryland increases the likelihood that military personnel will be Addresscorrespondenceandreprintrequeststo:BarbaraE.Wojcik, exposed to incidents that can cause TBI.6 The AFHSC PhD,CenterforAMEDDStrategicStudies(CASS),1608StanleyRoad, Suite 47, Fort Sam Houston TX 78234-5047. E-mail:barbara.wojcik@ reported that the largest relative increases in causes of amedd.army.mil. TBI-related hospitalizations after September 2001 were 0749-3797/00/$17.00 doi:10.1016/j.amepre.2009.10.006 relatedtobattlecasualtiesandweaponsaccidents.5Inthe S108 AmJPrevMed2010;38(1S):S108–S116 PublishedbyElsevierInc.onbehalfofAmericanJournalofPreventiveMedicine Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. 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THIS PAGE Same as 9 unclassified unclassified unclassified Report (SAR) Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Wojciketal/AmJPrevMed2010;38(1S):S108–S116 S109 current conflicts in Iraq and Afghanistan, exposure to (OperationEnduringFreedom[OEF])andIraq(Opera- blasts,motorvehiclecrashes,falls,andgunshotwounds tionIraqiFreedom[OIF]),10andArmysoldierscompose totheheadorneckarethemostcommonmechanismsof thelargestpercentageofthosedeployed.Basedonhead, braininjury.8 face,andneckinjuries,ithasbeenestimatedthatatleast SinceSeptember2001,approximately1.6millionU.S. 22%ofwoundedsoldiersevacuatedfromtheseconflicts military members have been deployed to Afghanistan have TBIs.5,11,12 One recent medical study, Table 1. Demographics of deployed U.S. Army population and the subset with TBI utilizing post-deploy- diagnosis admissions during deployment ment screening tools, concluded that 15% Afghanistan Iraq of returning soldiers Population AnyTBI Population AnyTBI had experienced a (n(cid:1)145,505) (n(cid:1)207) (n(cid:1)722,474) (n(cid:1)2,241) concussion, and one n (%) n (%) n (%) n (%) thirdofthosereported Gender injuries with loss of consciousness.13 Of Female 12,465 (8.6) 6 (2.9) 80,666 (11.2) 56 (2.5) soldierswithTBIsevac- Male 132,882 (91.3) 201 (97.1) 641,699 (88.8) 2,185 (97.5) uated to Walter Reed Unknown 158 (0.1) 0 (0.0) 109 (0.0) 0 (0.0) Army Medical Center Age(years) between January 2003 (cid:1)20 8,940 (6.1) 10 (4.8) 52,664 (7.3) 178 (7.9) and April 2005, 56% hadmoderateorsevere 20–29 79,230 (54.5) 143 (69.1) 400,628 (55.5) 1,483 (66.2) (includingpenetrating) 30–39 39,555 (27.2) 42 (20.3) 181,114 (25.1) 466 (20.8) TBIs.11,14 40–49 14,748 (10.1) 10 (4.8) 72,617 (10.1) 98 (4.4) There are a num- ber of different sys- (cid:1)50 3,026 (2.1) 2 (1.0) 15,444 (2.1) 16 (0.7) temsforcategorizing Unknown 6 (0.0) 0 (0.0) 7 (0.0) 0 (0.0) TBI,suchastheones Ethnicity used bytheAmerican White 98,519 (67.7) 150 (72.5) 471,896 (65.3) 1,592 (71.0) CongressofRehabilita- tive Medicine, WHO, African-American 24,522 (16.9) 16 (7.7) 133,219 (18.4) 273 (12.2) andtheCDC.8Anew Hispanic 13,465 (9.3) 23 (11.1) 72,865 (10.1) 224 (10.0) classifıcation of TBI Other 1,260 (0.9) 0 (0.0) 6,803 (0.9) 30 (1.3) was approved in 2001 by the International Unknown 7,739 (5.3) 18 (8.7) 37,691 (5.2) 122 (5.4) Collaborative Effort Component (ICE)onInjuryStatis- Activeduty 101,930 (70.1) 163 (78.7) 445,917 (61.7) 1,695 (75.6) ticswhenthegroupfı- Reserve 14,586 (10.0) 14 (6.8) 99,046 (13.7) 123 (5.5) nalizedtheBarellbody regionbynatureofin- NationalGuard 28,989 (19.9) 30 (14.5) 177,511 (24.6) 423 (18.9) jurydiagnosismatrix.15 Paygrade Documented by the Enlisted 118,487 (81.4) 185 (89.4) 619,819 (85.8) 2,097 (93.6) CDC,16 the matrix Officers 25,668 (17.60) 21 (10.1) 98,333 (13.6) 141 (6.3) standardizes data se- lectionofinjurycases Unknown 1,350 (0.9) 1 (0.5) 4,322 (0.6) 3 (0.1) for epidemiologic, Unitcategory clinical,andmanage- Combat 75,550 (51.9) 132 (63.8) 306,729 (42.5) 1,485 (66.3) mentanalyses. The Barell Matrix Combatservice 30,954 (21.3) 31 (15.0) 167,173 (23.1) 370 (16.5) classifıes TBI into Combatservicesupport 29,541 (20.3) 17 (8.2) 220,164 (30.5) 308 (13.7) threemutuallyexclu- Unknown 9,460 (6.5) 27 (13.0) 28,408 (3.9) 78 (3.5) sive types.15,17 Type TBI,traumaticbraininjury 1, the most severe January2010 S110 Wojciketal/AmJPrevMed2010;38(1S):S108–S116 form,includesdiagnoseswhere“thereisrecordedev- tained by the Army’s Patient Administration Systems and idence of an intracranial injury or a moderate or a BiostatisticsActivity.StandardInpatientDataRecordsare prolonged loss of consciousness...or injuries to the theoffıcialelectronicrecordsofhospitalizationsinDepart- opticnervepathways.Type2includesinjurieswithno mentofDefense(DoD)medicalfacilitiesworldwide.Data recorded evidence of intracranial injury, and loss of on helmet use were obtained from the Defense Casualty consciousness of less than one hour, or loss of con- InformationProcessingSystem(DCIPS)maintainedbythe sciousness of unknown duration, or unspecifıed level Army’sCasualtyandMemorialAffairsOperationsCenter. ofconsciousness.”Type3includesdiagnoses“withno TheDCIPSdatabasedocumentseachU.S.casualtyinclud- evidence of intracranial injury, and no loss of ing information on circumstances of the incident. Causal consciousness.” agent,mannerofintent,andmodeoftransportationwere Regardless of the classifıcation system used, soldiers obtained from the Joint Theater Trauma Registry (JTTR) withTBIappeartorepresentalargerproportionofU.S. developed by the Center for Army Medical Department casualtiesinIraqandAfghanistancomparedtothosein (AMEDD) Strategic Studies18 and maintained by the U.S. otherrecentconflicts.11,12Thus,thereisaneedforexten- ArmyInstituteofSurgicalResearch. sive research to estimate TBI incidence rates in both AdmissionsincludedinthisstudywerefromArmyfacilities campaigns and to evaluate the impact of TBI among locatedbothin-theaterandinEuropeandtheU.S.ifthesol- deployedtroops.SuchresearchcanhelptheU.S.Armyto dierswereevacuatedfromtheater.Episodesofcarewerecre- improvemeasurestobothdiminishtheriskofTBIinjury atedfromtheadmissionrecordssothatifasoldiermovedfrom onefacilitytoanotherforadditionalcare,therewouldbeonly andimprovehealthpolicies.Thesepoliciesmayinclude one record per casualty incident. Hospitalizations within 10 better identifıcation of TBI and improved provision of daysofeachotherwereoneepisode.TBIepisodeswereidenti- medicalresourcestocareforTBIcases.Thepurposeof fıed by ICD-9-CM diagnosis codes using the Barell Matrix thisstudywastoestablishbenchmarkadmissionrates classifıcationscheme.16Diagnosiscodeswereclassifıedintothe at U.S. Army medical treatment facilities for soldiers threeTBItypesasfollows: with TBIs identifıed during deployment to Iraq and Afghanistan. ● Type 1 (the most severe): 800, 801, 803, and 804 (plus fourthandfıfthdigits:0.03–0.05,0.1–0.4,0.53–0.55,0.6– 0.9);850(0.2–0.4);851–854;950(0.1–0.3). Methods ● Type2:800,801,803,and804(plus0.00,0.02,0.06,0.09, 0.50,0.52,0.56,0.59);850(0.0,0.1,0.5,0.9). Data for this study were obtained from several existing data- Table 2. Distribution of TBI hospitalizationsa by location and injury type bases. Population Location/injurytype TBIb data for soldiers de- ployed in Afghani- Type1 Type2 Type3 Any stan and Iraq from n (%) n (%) n (%) n (%) the beginning of the Afghanistan campaigns (Septem- ber 11, 2001 in Af- Battleinjury 35 (40.7) 48 (31.8) 3 (37.5) 85 (35.9) ghanistan;October1, Nonbattleinjury 51 (59.3) 103 (68.2) 5 (62.5) 152 (64.1) 2002inIraq)through Total 86 151 8 237 September 30, 2007, including demogra- Iraq phicsanddatesofar- Battleinjury 751 (60.7) 660 (46.9) 55 (44.0) 1399 (52.6) rival and departure Nonbattleinjury 487 (39.3) 747 (53.1) 70 (56.0) 1262 (47.4) from theater, were providedbytheDefense Total 1238 1407 125 2661 ManpowerDataCenter. Overall Inpatient healthcare Battleinjury 786 (59.4) 708 (45.4) 58 (43.6) 1484 (51.2) dataforthesesoldiers during their deploy- Nonbattleinjury 538 (40.6) 850 (54.6) 75 (56.4) 1414 (48.8) ments were obtained Total 1324 1558 133 2898 fromtheStandardIn- aDuringdeployment,forU.S.ArmysoldiersdeployedbetweenSeptember11,2001,andSeptember30,2007. patient Data Record bType1TBI(mostsevere),Type2,andType3(leastsevere)refertoBarellInjuryMatrixcategories.15 (SIDR) database main- TBI,traumaticbraininjury www.ajpm-online.net Wojciketal/AmJPrevMed2010;38(1S):S108–S116 S111 ● Type 3 (the least severe): 800, 801, 803, and 804 (plus Helmet-usedatafromtheDCIPSfılespecifıedwhether 0.01,0.51). a helmet was worn, not worn, or unknown during the The fırst eight diagnoses from each admission were incidentthatcausedtheTBI.DataonhelmetuseintheDCIPS checkedforpresenceofaTBIdiagnosis.Eachepisodewas casualtyrecordswasverysparsepriortoApril2005,andanal- classifıedastothepresenceorabsenceofoneormoreTBI yses were restricted to battle injury episodes occurring from diagnoses(“AnyTBI”)andthepresenceorabsenceofeach April2005throughSeptember2007.Directmechanism(e.g., type of TBI. In analyses, an episode could be counted in blunt,explosion,penetrating)ofinjuryandcausalagentcate- morethanonecategory,butonlyoncewithineachcategory. gories(e.g.,munitionsandexplosives,motorvehiclecrashes) For example, suppose an episode consisted of two admis- from the JTTR data were also added to the episode of care sions (fırst admission: one Type 1 diagnosis, one Type 2 recordsandsummarizedbytheaterandTBIcategory. diagnosis;secondadmission:twoType2diagnoses).Then Episodes were summarized by fırst date of admission theepisodewouldcountoncein“AnyTBI,”onceinType1 and merged with daily deployed soldier population TBI,andonceinType2TBI. countstoobtainTBIandtotalinjuryoccurrencerates.All Variablesincludedgender(male,female);agegroup((cid:1)20, rates were determined as the number of episodes per 20–29, 30–39, 40–49, 50(cid:2)); ethnicity/race (white, African 10,000soldier-years. American,Hispanic,other);rank(enlisted,offıcer);unitcate- RiskanalyseswereconductedusingmultivariatePoisson gory(combat,combatsupport,combatservicesupport);army regressionforTypes1–3and“AnyTBI”foreachcampaign. component(activeduty,NationalGuard,Reserve);andforOIF Factors examined included gender, age group, ethnicity/ only, campaign phase based on deployment dates (buildup: race,rank,unitcategory,component,andcampaignphase September1,2002,throughMarch19,2003;combat:March (Iraqonly). 30, 2003 through April 30, 2003; stabilization: May 1, 2003, AlldataanalyseswereperformedusingSASversion9.1.3 throughSeptember30,2007).Episodesweresummarizedby software. Relative risks were determined using the SAS operation(Afghanistan,Iraq);TBIcategory(Type1–Type3, GENMODprocedure.Inallanalyses,p-valueslessthan0.05 Any);andinjurytype(battleinjury,nonbattleinjury).Battle wereconsideredsignifıcant. injurieswereidentifıedbytheNorthAtlanticTreatyOrganiza- Results tion (NATO) Standardization Agreement (STANAG) 2050 traumaandcause-of-injurycodes.19Reasonsforadmissionfor Of 145,505 individuals deployed to Afghanistan, 0.14% both battle and nonbattle injuries were determined by ICD- had one or more TBI-related hospitalizations during 9-CMprincipaldiagnosiscodes. their deployments (Table 1). In Iraq, Table 3. Direct mechanism of injury for TBI hospitalizationsa matched to JTTR records 0.31%of722,474de- ployed soldiers were Location/direct TBIb hospitalizedwithTBI mechanism Type1 Type2 Type3 Any diagnosesduringde- n (%) n (%) n (%) n (%) ployment. Although Afghanistan men were approxi- mately 90% of de- Explosion 23 (65.7) 19 (34.5) 1 (25.0) 42 (46.7) ployedsoldierpopula- Blunt 4 (11.4) 21 (38.2) 1 (25.0) 24 (26.7) tions, they accounted Penetrating 4 (11.4) 5 (9.1) 1 (25.0) 10 (11.1) for97%ofTBI-related Other 4 (11.4) 10 (18.2) 1 (25.0) 14 (15.6) hospitalizations in boththeatersofoper- 35 (100.0) 55 (100.0) 4 (100.0) 90 (100.0) ation. Soldiers aged Iraq 20–29 years repre- Explosion 478 (67.8) 334 (58.1) 56 (64.4) 829 (63.9) sented about 55% of both deployed popu- Blunt 94 (13.3) 154 (26.8) 21 (24.1) 248 (19.1) lations,butaccounted Penetrating 116 (16.5) 22 (3.8) 9 (10.3) 143 (11.0) formorethan66%of Burn 1 (0.1) 1 (0.2) 0 (0.0) 1 (0.1) those hospitalized Other 16 (2.3) 64 (11.1) 1 (1.1) 77 (5.9) withTBIinbothcam- paigns. Also in both 705 (100.0) 575 (100.0) 87 (100.0) 1298 (100.0) theaters, beginning aDuringdeployment,forU.S.ArmysoldiersdeployedbetweenSeptember11,2001,andSeptember30,2007. withthoseaged20–29 bType1TBI(mostsevere),Type2,andType3(leastsevere)refertoBarellInjuryMatrixcategories.15 JTTR,JointTheaterTraumaRegistry;TBI,traumaticbraininjury years, there was an January2010 S112 Wojciketal/AmJPrevMed2010;38(1S):S108–S116 overalltrendofdecreasingincidenceofTBIwithincreasing AnyTBIadmission,64%and47%werecausedbyexplosion age group. Another similarity found in both theaters was (IraqandAfghanistan,respectively),19%and27%byblunt thatenlistedsoldiersaccountedforan8%greaterpropor- mechanismofinjury,and11%bypenetratingdirectmecha- tion of total TBI admissions compared to their respective nisminbothcampaigns. proportionsofthedeployedpopulations. AprofıleofhelmetusebyTBIcategoryandtheateris When TBI episodes were summarized by injury type presentedinTable4.RecallthatthesumofthethreeTBI (Table 2), the majority of total admissions (over 51%) typescanbegreaterthanthenumberofAnyTBI(which wererelatedtobattleinjuries.However,TBIhospitaliza- isthenumberofuniqueTBIepisodes).Duringtheperiod tionsdemonstrateddifferentprofılesineachtheater.Bat- whenhelmet-usedatawerepopulated(April1,2005,to tle injury admissions associated with TBI Type 1 ac- September 30, 2007), there were 1047 TBI battle injury countedfor61%ofTBIepisodesinIraqandonly41% episodes of care. The results show that in both theaters, in Afghanistan. Type 2 TBI admissions were related regardlessofTBIcategory,themajorityofthosesustaining mostlytononbattleinjuryepisodes(Afghanistan:68%; TBIs were wearing their helmets at the time of the injury Iraq:53%). incident. In fact, at least 77% of soldiers sustaining Any When the JTTR data were merged with the TBI epi- TBI were wearing their helmetswheninjured(Afghani- sodes, matches were obtained for 1388 (48%) TBI epi- stan:77%;Iraq:79%). sodes(Iraq:1298[49%];Afghanistan:90[38%];Table3). Relative risk analyses for TBI by campaign were per- Distributionofthedirectmechanismofinjurywasfairly formed,andresultsforAnyTBIaresummarizedinTable5. consistentacrossTBIcategoriesinIraq,withexplosions In Afghanistan, enlisted soldiers experienced a higher accountingforthemajorityofallTBIs,from58%ofType risk of TBI-related hospitalizations than offıcers (2.5 for 2 to as much as 68% of Type 1. Results in Afghanistan Type1to1.5forType2).NationalGuardsoldiersdemon- weremorevariable,withexplosionsaccountingfor66% strated signifıcantlylowerriskthanactivedutysoldiers(ap- ofType1TBI,butonly47%ofAnyTBIandlessthan35% proximatelyonehalftheriskforTBIType2and21%lessrisk of Type 2 TBI episodes. About two thirds of Type 1 forTBIType1);andthosepersonnelassignedtocombatunits episodes were due to munitions and ex- Table 4. Wearing of helmet as reported in DCIPS, matched to TBI battle injury plosivesinbothcam- hospitalizationsa paigns, followed in Afghanistan by fıre- Location/helmet TBIb arms(11%)andfalls wear Type1 Type2 Type3 Any (11%) and inIraqby n (%) n (%) n (%) n (%) fırearms (17%) and Afghanistan motorvehiclecrashes (9%). Munitions and Worn 17 (70.8) 30 (83.3) 1 (50.0) 48 (77.4) explosives also ac- Notworn 3 (12.5) 2 (5.6) 0 (0.0) 5 (8.1) counted for the ma- Unknown 4 (16.7) 4 (11.1) 1 (50.0) 9 (14.5) jority of the other 24 36 2 62 TBI categoriesinIraq. However, in Afghani- Iraq stan,munitionsandex- Worn 372 (78.3) 424 (80.0) 22 (66.7) 779 (79.1) plosives, although the Notworn 45 (9.5) 23 (4.3) 3 (9.1) 67 (6.8) leading causal agent, Unknown 58 (12.2) 83 (15.7) 8 (24.2) 139 (14.1) accountedforonly35% of Type 2 and 47% of 475 530 33 985 AnyTBI.Inbothcam- Total paigns, motor vehicle Worn 389 (78.0) 454 (80.2) 23 (65.7) 827 (79.0) crashes were the sec- ond leading causal Notworn 48 (9.6) 25 (4.4) 3 (8.6) 72 (6.9) agent for Type 2 (Af- Unknown 62 (12.4) 87 (15.4) 9 (25.7) 148 (14.1) ghanistan: 26%; Iraq: 499 566 35 1047 almost 18%). When aLimitedtoTBIbattleinjuryhospitalizationswhichoccurredbetweenApril1,2005,andSeptember30,2007. comparing direct bType1TBI(mostsevere),Type2,andType3(leastsevere)refertoBarellInjuryMatrixcategories.15 mechanismprofılesfor DCIPS,DefenseCasualtyInformationProcessingSystem;TBI,traumaticbraininjury www.ajpm-online.net Wojciketal/AmJPrevMed2010;38(1S):S108–S116 S113 Table 5. Relative risks (RRs) of hospitalization for any TBI during deploymenta support units. Fi- nally,therewasagen- Afghanistan Iraq eral pattern of de- Characteristic RRb (95%CI) RRb (95%CI) creasing risk with Gender increasing age for Types 1 and 2, with Male 1.00 (baseline) 1.00 (baseline) the notable exception Female 0.37 (0.24,0.57) 0.30 (0.26,0.36) for those in the 50(cid:2) Age(years) category. In addition, (cid:1)20 1.00 (baseline) 1.00 (baseline) in Iraq an increasing trend in TBI risk was 20–29 0.57 (0.48,0.68) 0.79 (0.74,0.84) associated with the 30–39 0.37 (0.26,0.51) 0.51 (0.45,0.57) phase of the cam- 40–49 0.32 (0.15,0.68) 0.40 (0.29,0.55) paign,withthestabili- (cid:1)50 — — 1.48 (1.35,1.62) zation phase having thegreatestrisk. Race/ethnicity In general, the in- White 1.00 (baseline) 1.00 (baseline) cidenceofTBIhospi- Black 0.48 (0.37,0.63) 0.68 (0.63,0.73) talizationsduringde- ployment increased Hispanic 1.37 (1.08,1.75) 0.97 (0.88,1.07) over time. Table 6 Grade presents yearly and Officer 1.00 (baseline) 1.00 (baseline) overall admission Enlisted 1.86 (1.46,2.38) 1.94 (1.76,2.15) rates per 10,000 sol- dier-years for the Component most severe form of Activeduty 1.00 (baseline) 1.00 (baseline) TBI(Type1)andfor NationalGuard 0.64 (0.52,0.78) 0.71 (0.66,0.75) theoccurrenceofany Reserve 1.01 (0.76,1.34) 0.55 (0.49,0.62) TBI-related hospital episodesofcare(Any Unittype TBI).OverallTBI-re- Combat 1.00 (baseline) 1.00 (baseline) latedadmissionrates Combatsupport 0.62 (0.51,0.76) 0.62 (0.57,0.66) in Iraq were signifı- cantlyhigherthanin Combatservicesupport 0.44 (0.34,0.57) 0.38 (0.35,0.41) Afghanistan (Pois- Campaignphasec son regression, p(cid:1) Stabilization — — 1.00 (baseline) 0.0001). For both Build-up — — 0.33 (0.29,0.38) Iraq and Afghani- stan,AnyTBIadmis- Combat — — 0.51 (0.46,0.57) sionratesandType1 aU.S.ArmysoldiersdeployedbetweenSeptember11,2001,andSeptember30,2007 TBI rates were posi- bHighlightedvaluesimplysignificantrelativeriskatthe0.05levelofsignificance. cApplicableonlytoIraq tively correlated with CI,confidenceinterval;TBI,traumaticbraininjury time (Iraq: Any TBI, r(cid:3)0.81, p(cid:3)0.05; Type presentedgreaterriskthanthoseincombatsupportorcombat 1,r(cid:3)0.70,p(cid:3)0.06;Af- servicesupportunits.Withregardtoage,therewasatrendof ghanistan:AnyTBI,r(cid:3)0.88,p(cid:3)0.008;Type1,r(cid:3)0.74, decreasingriskwithincreasingage. p(cid:3)0.058). In both theaters of operation, there was a OneseesmanyparallelresultswithintheIraqcampaign. major increase in Any TBI rates in 2004 compared to Enlistedpersonnelexperiencedfrom1.5toalmost3timesthe previous years, with a sevenfold increase in Afghani- riskcomparedtooffıcers.NationalGuardandreservistsdem- stan and a twofold increase in Iraq. Rates then re- onstratedlowerriskthanactiveduty(30%and45%lessrisk, mained relatively constant until 2007, when an ap- respectively).Thoseservingincombatunitswereatgreatest proximately twofold increase occurred in both riskrelativetothoseincombatsupportandcombatservice AfghanistanandIraq. January2010 S114 Wojciketal/AmJPrevMed2010;38(1S):S108–S116 Table 6. Type 1 TBIa and any TBI hospitalization ratesb TBI and Type 3 categories and the sharp increases in per 10,000 soldier-years Any TBI and Types 1 and 2 from 2006 to 2007. In Afghanistan sharp increases occurred from 2006 to Year Afghanistan Iraq 2007inAnyTBIandTypes1and2. Type1 AnyTBI Type1 AnyTBI 2001 3.7 3.7 — — Discussion 2002 4.4 12.6 0.0 22.8 Traumaticbraininjuryhasbeenrecognizedasthe“sig- 2003 2.9 7.9 10.4 19.3 nature wound” of the current conflicts in Iraq and Af- 2004 10.7 26.4 23.0 39.6 ghanistan.20,21 Recent surveys indicate that approxi- mately 17%–22% of returning soldiers could have 2005 11.1 28.4 17.9 37.6 TBIs.5,7,11,12 2006 6.7 24.5 17.7 42.4 Severalpapershavebeenpublishedinrecentyearsthat 2007 21.1 56.6 31.3 77.9 concentrated on post-deployment detection and treat- Overall 8.9c 24.6d 19.4c 41.8d ment of primarily mild TBIs.6,13,22,23 In contrast, this study sought to establish baseline data on the generally aBarellInjuryMatrixcategoryformoresevereTBI15 bDuringdeployment,forU.S.ArmySoldiersdeployedbetweenSep- moresevereTBI-relatedhospitalizationsofsoldiersdur- tember11,2001,andSeptember30,2007 ingtheirdeployments.Thestudylimitationsincludethe cOverallhospitalizationrateforType1TBIwassignificantlyhigherin useofsecondarydata,theexclusionofundiagnosedTBIs, IraqcomparedtoAfghanistan(Poissonregression,p(cid:1)0.0001). dOverallhospitalizationrateforAnyTBIwassignificantlyhigherinIraq andthelackofdataregardinghelmetusepriortoApril comparedtoAfghanistan(Poissonregression,p(cid:1)0.0001). 2005. The episodes of care span admissions at combat TBI,traumaticbraininjury support hospitals in the theater through evacuations to ArmyfacilitiesinGermanyandtheU.S.A10-yearsur- In examining population-based rates of TBI occur- veillance(1997–2006)ofTBIoccurrenceinU.S.military rence, the rates for all injury occurrences were also worldwide(bothbattleandnonbattleinjury)reportedan reviewed,andincreasingtrendsinbothwereobserved. overallArmyrateof93.9medicalencounters(outpatient In order to determine the relative increase in TBI and hospitalizations) for TBI per 10,000 soldier-years.5 comparedtoallinjuries,TBIratesper10,000soldier- LookingatTBIhospitalizationsduringdeployment,the years as a percentage of all injury rates per 10,000 currentstudyfoundanoverallrateof24.6forAfghani- soldier-years were examined (Figure 1). In both Af- stan and 41.8 for Iraq per 10,000 soldier-years. In both ghanistan and Iraq, there were marked increasing theaters, there was an increase in both Type 1 and Any trendsinTypes1and2andAnyTBIaspercentagesof TBIratesfrom2006to2007. all injuries, with sharp increases from 2006 to 2007. Basedontheanalysis,TBIepisodesin2007constitutedsim- Type 3 rates as percentages of all injury rates had ilarpercentagesofallinjuryhospitalizationsinbothIraqand relatively flat slopes. When examining the Iraq plot, Afghanistan(27%and28%,respectively.)Thesepercentages onenotesthecontinuedincreasewithtimeoftheAny representedsignifıcantincreasesoverlevelsfromthefırstfull 30 30 Opera(cid:1)on Enduring Freedom Operation Iraqi Freedom s 25 es 25 e of total injurie 1250 ge of total injuri 1250 ntag 10 enta 10 e c erc 5 Per 5 P 0 0 2002 2003 2004 2005 2006 2007 2002 2003 2004 2005 2006 2007 Type 1 Type 2 Type 3 Any TBI Type 1 Type 2 Type 3 Any TBI Figure 1. Tramatic brain injury (TBI) hospitalization episode rates as percentages of total injury rates Note: All rates were expressed as per 10,000 soldier-years. www.ajpm-online.net Wojciketal/AmJPrevMed2010;38(1S):S108–S116 S115 yearinbothcampaigns(19%increaseinIraqand18%inAf- References ghanistan).TheascendingtrendintheTBI-relatedproportion 1. Sutton LK. From the director. DCoE in Action 2009;2(2):2. ofallinjuryhospitalizationsmaybearesponsetoincreased www.dcoe.health.mil. awarenessanddetectionofTBI.Forexample,theDefenseand 2. Centers for Disease Control and Prevention (CDC). Facts VeteransBrainInjuryCenter(DVBIC)developedtwoscreen- abouttraumaticbraininjury.July2006.www.cdc.gov/ncipc/ ingtools:theMilitaryAcuteConcussionEvaluation(MACE) tbi/Factsheets/Facts_About_TBI.pdf. forin-theaterscreeningandtheBriefTBIScreen(BTBIS)for 3. LangloisJA,Rutland-BrownW,ThomasKE.Traumaticbrain postdeploymentscreening,whichhaveimprovedtheproper injuryintheUnitedStates:emergencydepartmentvisits,hos- diagnosisandtreatmentofTBI.24 pitalizations,anddeaths.AtlantaGA:CDC,NationalCenter forInjuryPreventionandControl,2006. As a result of this study, several potential risk factors 4. Army Medical Surveillance Activity. Hospitalizations for for TBI-related, in-theater hospitalization were identi- assault-relatedinjuries,activecomponent,U.S.ArmedForces, fıed. In both campaigns, female soldiers demonstrated January 1998–June 2007. Med Surveill Mon Rep 2008; abouta70%decreasedriskofanyTBIadmission,butitis 15(1):2–8. notknownwhetherthislowerrateisindicativeofnonde- 5. ArmyMedicalSurveillanceActivity.Traumaticbraininjury among members of active components, U.S. Armed Forces, ployment to combat units, the use of more protective 1997–2006.MedSurveillMonRep2007;14(5):2–6. equipment,orgreatercautionbyfemalesoldiers.Addi- 6. UnitedStatesGovernmentAccountabilityOffıce.Mildtrau- tional studies are needed to answer these questions. As maticbraininjuryscreeningandevaluationimplementedfor expected, combat support and combat service support OEF/OIF Veterans, but challenges remain. February 2008. units experienced much lower risk of TBI hospitaliza- www.gao.gov/new.items/d08276.pdf. tions than combat units. Findings indicate a decreased 7. HarbenJ.TraumaticBrainInjuryTaskForcereport.January trendofTBIriskwithsoldier’sage,potentiallyduetothe 2008.www.armymedicine.army.mil/reports/reports.html. 8. Traumatic Brain Injury Task Force. Report to the Surgeon greater caution that comes with experience. Future re- General, May 15, 2007. www.armymedicine.army.mil/ searchshouldexamineiftheaboverelationshipisafunc- reports/reports.html. tionofyearsofservice. 9. GalarneauMR,WoodruffSI,DyeJL,MohrleCR,WadeAL. Ananalysisofhelmetuserevealedthatmorethan70% TraumaticbraininjuryduringOperationIraqiFreedom:fınd- of soldiers with TBI (all categories except for Type 3) ings from the United States Navy—Marine Corps Combat werewearingheadprotectionatthetimeoftheinjury TraumaRegistry.JNeurosurg2008;108:950–7. 10. TanielianT,JaycoxLH,eds.Invisiblewoundsofwar:psycho- incident.InAfghanistan,12.5%ofsoldierssustaininga logicalandcognitiveinjuries,theirconsequences,andservices Type1TBIwerenotwearingahelmet;similarly,9.5% toassistrecovery.SantaMonicaCA:TheRandCorporation, in Iraq. Follow-up analysis as to why helmets were not 2008.www.rand.org. usedisrecommended. 11. Warden DL. Military TBI during the Iraq and Afghanistan Asexpectedwithdeployedsoldiers,themajorityofType wars.JHeadTraumaRehabil2006;21:398–402. 1TBIcaseswerecausedbyexplosives(Afghanistan:66%; 12. OkieS.Traumaticbraininjuryinthewarzone.NEnglJMed Iraq:68%).Whencomparingdirectmechanismprofılesfor 2005;352:2043–7. 13. HogeCW,McGurkD,ThomasJL,CoxAL,EngelCC,Castro anyTBIadmission,64%and47%arecausedbyexplosion CA. Mild traumatic brain injury in U.S. Soldiers returning (IraqandAfghanistan,respectively).Increasednumbersof fromIraq.NEnglJMed2008;358:453–63. IEDsinrecentyearsareprobablyprimarilyresponsiblefor 14. WardenDL,RyanLM,HelmickKM,etal.Warneurotrauma: theabovestatistics.Bettermethodsofpreventionneedtobe theDefenseandVeteransBrainInjuryCenter(DVBIC)expe- explored to protect soldiers more effectively from future rienceatWalterReedArmyMedicalCenter(WRAMC)[ab- IEDattacks.Inconclusion,theU.S.Armyfacesmajorchal- stract].JNeurotrauma1996;40:211–7. 15. BarellV,Aharonson-DanielL,FingerhutLA,etal.Anintro- lenges in the prevention, identifıcation, and treatment of ductiontotheBarellbodyregionbynatureofinjurydiagnosis TBIstodecreasetheserates.Tomeasurethesuccessofthe matrix.InjPrev2002;8:91–6. Army’sfuturepreventiveinterventions,weproposeongo- 16. CDC.TheBarellinjurydiagnosismatrix,classifıcationbybody ing surveillance to monitor TBI hospitalization rates region and nature of injury. www.cdc.gov/nchs/data/ice/ in-theater. fınal_matrix_post_ice.pdf. 17. CDC.InternationalCollaborativeEffort(ICE)oninjurysta- tistics.ChangestothematrixforMay2002update.www.cdc. The opinions expressed herein are those of the authors gov/nchs/about/otheract/ice/amputat.htm. and do not reflect the offıcial policy or position of the 18. AbbottCA.Developmentofamilitarytraumaregistry:JTTR. DepartmentoftheArmy,theDepartmentofDefense,or SanAntonioTX:CenterforArmyMedicalDepartmentStra- theU.S.Government. tegicStudies,2009.RP09-002(availablefromDTIC). Nofınancialdisclosureswerereportedbytheauthors 19. JonesBH,AmorosoPJ,CanhamML,WeyandtMB,Schmitt ofthispaper. JB,eds.AtlasofinjuriesintheU.S.ArmedForces.MilMed 1999;164(8S):S633. January2010 S116 Wojciketal/AmJPrevMed2010;38(1S):S108–S116 20. MartinEM,WeiCL,HelmickK,FrenchL,WardenDL.Trau- screening tool for traumatic brain injury. J Head Trauma matic brain injuries sustained in the Afghanistan and Iraq Rehabil2007;22(6):377–89. wars.AmJNurs2008;108(4):40–7. 23. Gaylord KM, Cooper DB, Mercado JM, Kennedy JE, 21. Cajigal S. Taking the “mild” out of mild traumatic brain Yoder LH, Holcomb JB. Incidence of posttraumatic stress injury. July 3, 2007. Neurology Today;7(13):21–22. www. disorder and mild traumatic brain injury in burned ser- neurotodayonline.com/. vice members: preliminary report. J Trauma 2008;(64S): 22. SchwabKA,IvinsB,CramerG,etal.Screeningfortraumatic S200–6. braininjuryintroopsreturningfromdeploymentinAfghan- 24. JaffeeMS.MessagefromNationalDirector,DVBIC.DVBIC istanandIraq:initialinvestigationoftheusefulnessofashort Brainwaves2009winter:1.www.DBVIC.org. www.ajpm-online.net