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Cardiovascular Disease-related Medical Evacuations, Active and Reserve Components, U.S. Armed Forces, 1 October 2001–31 December 2017

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Medical Surveillance Monthly Report


From 1 October 2001 through 31 December 2017, a total of 697 medical evacuations of service members from the U.S. Central Command (CENTCOM) area of responsibility were followed by at least one medical encounter in a fixed medical facility outside the operational theater with a diagnosis of a cardiovascular disease (CVD). The vast majority of those (n=660; 94.7%) evacuated were males. More than a third of CVD-related evacuations (n=278, 39.9%) occurred in service members 45 years of age or older; slightly more than half (n=369; 52.9%) occurred in reserve or guard members. The most common CVD risk factors which had been diagnosed among evacuated service members prior to their deployment were hypertension (n=236; 33.9%) and hyperlipidemia (n=241; 34.9%). Much lower percentages had been previously diagnosed with obesity (n=74, 10.6%) or diabetes (n=21, 3.0%). More than 1 in 4 service members with a CVD-related medical evacuation had been diagnosed with more than one risk factor (n=182, 26.1%). Both limitations to the data available and strategies to reduce CVD morbidity in theater are discussed.


This is the first MSMR summary of cardiovascular-related medical evacuations from the CENTCOM AOR. The highest rates of evacuation occurred in males, those 45 years of age or older, senior officers and warrant officers, and members of the reserve or guard. A third of evacuees had pre-deployment diagnoses of the modifiable risk factors hypertension or hyperlipidemia.


Pre-deployment medical screening should continue to ensure that service members meet the minimal standards of fitness for deployment to CENTCOM AOR. Service members with hypertension or hyperlipidemia controlled on a medication regimen should be stable for at least 90 days prior to deployment.


Since the beginning of military operations in the U.S. Central Command (CENTCOM) area of operation (AOR) in 2001, there have been over 50,000 medical evacuations from the CENTCOM AOR. Throughout this period, disease and non-battle injury (DNBI) have accounted for at least three quarters of medical evacuations. During periods of limited combat operations, over 90% of medical evacuations have been due to DNBI.1-3

Medical evacuations have a significant impact on military readiness due to loss of personnel and the resultant effects on unit cohesion and mission effectiveness. The costs of medical evacuation related to DNBI are also considerable; one estimate of the cost of medical evacuations from the CENTCOM AOR between 2008 and 2013 was in excess of $300 million dollars.4

The U.S. military has developed policy related to deployment standards which are applied during the pre-deployment screening process to determine medical and psychological fitness to deploy. As part of this process, potential deployers complete DD Form 2795 (Pre-Deployment Health Assessment or Pre-DHA) which is reviewed by a health care provider to help identify and address medical issues which might impact deployment medical readiness. During pre-deployment screening, a service member can receive a referral to a primary or specialty care provider for further evaluation of a specific condition if necessary. If a service member is determined to be unfit for deployment or nondeployable, he or she can request a medical deployment waiver which (if approved) will permit deployment of the service member.5,6

A recent retrospective cohort study in Army personnel evaluated the impact of receiving a medical deployment waiver on the subsequent probability of being medically evacuated for DNBI causes from the CENTCOM AOR. This study reported that soldiers receiving a waiver were more than twice as likely to be medically evacuated for DNBI as matched controls without waivers (relative risk[RR]:2.03; 95% CI: 1.74–2.36). Notably, the greatest number of waivers granted to soldiers during the study period (2008–2013) were for cardiology/pulmonary conditions.4

Some additional insight into the prevalence of cardiovascular disease (CVD) in deployed personnel can be gleaned from published literature. A prior MSMR report on deaths attributed to cardiovascular causes occurring in the CENTCOM AOR documented 62 such deaths between October 2001 and December 2012.7 An analysis evaluating the burden of disease in theater reported that more than 7,800 medical encounters in male service members in 2017 were attributable to CVDs; this represents 5.5% of all medical encounters in deployed servicemen during the year.8

Published reports from cardiology consultants at combat support hospitals provide limited data on the extent of cardiac disease requiring medical evacuation. Two studies conducted in Iraq between 2004 and 2005 and Afghanistan between 2010 and 2013 reported evacuation rates of 14% and 15%, respectively, for military members referred for cardiac symptoms.9,10 However, a paucity of literature exists providing a comprehensive summary of medical evacuations from the CENTCOM AOR related to cardiovascular diagnoses.

This descriptive analysis summarizes the demographic characteristics, counts, rates and temporal trends for CVD-related medical evacuations from the CENTCOM AOR. In addition, the percentage of those evacuated who had received pre-deployment diagnoses indicating cardiovascular risk is summarized. Responses to questions regarding health status and physician referrals on the DD2795 are also summarized.


The surveillance period was 1 October 2001 through 31 December 2017. The surveillance population included all members of the active and reserve components of the U.S. Army, Navy, Air Force and Marine Corps who were deployed as part of operations in the CENTCOM AOR in Southwest Asia. Medical evacuations were included in the analysis if the evacuated service member was evacuated from CENTCOM to a medical treatment facility outside the CENTCOM AOR and if the service member had at least one outpatient or inpatient medical encounter during the time period from 5 days before to 10 days after the reported evacuation date. Evacuations were included only if they occurred after the start date of a service member’s deployment and within 90 days after the end of the deployment.

Deployment records were available from the Defense Manpower Data Center Contingency Tracking System and are archived in the Defense Medical Surveillance System (DMSS). Records of all medical evacuations conducted by the U.S. Transportation Command (TRANSCOM) and maintained in the TRANSCOM Regulating and Command System (TRAC2ES) were used as the source of evacuation data. Medical encounter data and data from the Pre-Deployment Health Assessment form (DD2795) are provided for health surveillance purposes to the Armed Forces Health Surveillance Branch and archived in DMSS. Evacuations were classified as CVD related based on International Classification of Disease diagnostic codes (ICD-9/ ICD-10) reported in the first recorded hospitalization or outpatient medical encounter outside the CENTCOM AOR during the time period outlined above. These codes are listed in Table 1. Diagnoses for CVD were considered the reason for the subject evacuation if they were documented in the first or second diagnostic position. For this analysis, one medical evacuation per deployment was counted.

Denominators for rates of medical evacuations were calculated by determining the length of each individual’s deployment and summing the person-time of all deployers. If the deployment end date was missing, the end date was imputed based on average deployment times per service.

All pre-deployment Health Assessment Forms (DD2795s) completed within 120 days of start date of the linked deployment were identified for each case. If multiple forms were identified during this step, the form completed on a date closest to the start of the deployment was retained.

The presence or absence of predeployment cardiovascular risk factors were ascertained for all service members identified as a “case” of CVD-related medical evacuation. The specific cardiovascular risk factors evaluated were hypertension, hyperlipidemia, obesity, abnormal blood glucose, and diabetes. Each risk factor was defined with a specific set of ICD-9 and ICD-10 codes as outlined in Table 1. If any of the specific diagnostic codes was identified in any diagnostic position of a record of an ambulatory medical encounter or hospitalization at any point before the start date of the relevant deployment, the risk factor was classified as being present predeployment (i.e., prior to deployment).


During the surveillance period, a total of 697 medical evacuations of service members from CENTCOM AOR were related to CVD. The overall rate of CVD-related evacuations was 0.3 per 1,000 deployed person-years (dp-yrs) (Table 2).

Overall, more than 17 times as many males (n=660) as females (n=37) were medically evacuated for cardiovascular diagnoses and the rate of evacuations in males (0.32 per 1,000 dp-years) was twice that in females (0.16 per 1,000 dp-yrs). (Table 2) The diagnoses most frequently associated with CVD-related medical evacuations were coronary atherosclerosis, acute myocardial infarction, and cerebral artery occlusion (data not shown).

The rates of CVD-related medical evacuation increased with  age and the highest rate of evacuation occurred in those 45 years of age or older (2.6 per 1,000 dp-yrs). Rates in this age category were more than twice that of those in the 40-44 year old age category (1.0 per 1,000 dp-yrs). Rates in service members under 30 years of age were relatively low (0.1 per 1,000 dp-yrs).
Overall, CVD-related medical evacuation rates were highest among black, non-Hispanic service members (0.4 per 1,000 dp-yrs) and lowest among service members of “other” or unknown race/ethnicity (0.2 per 1,000 dp-yrs). Compared to their respective counterparts, rates of CVDrelated evacuation were higher among deployers in the Army and in armor/motor transport or healthcare occupations. Notably, the reserve component service member rate of CVD-related evacuation (0.6 per 1,000 dp-yrs) was three times that of members of the active component  (0.2  per 1,000 dp-yrs). Senior officers and warrant officers had the highest overall rates of CVD-related medical evacuations (0.7 per 1,000 dp-yrs) although they comprised only 9.9% and 4.5% of all CVD-related evacuations, respectively.

Almost 1 in 4 of the service members who were evacuated for a CVD diagnosis endorsed having either a medical problem (n=107; 15.4%) or a health concern (n=57; 8.2%) when completing the pre-deployment health assessment form (DD275). Relatively few were given a cardiac (n=2; 0.3%), primary care (n=1; 0.1%), or other referral (n=10; 1.4%). Twenty-two service members (3.2%) were determined to be "non-deployable". Almost 1 in 5 of the evacuated service members (n=135; 19.4%) did not have a DD2795 available at the time of analysis (Table 3).

In the separate examination of cardiovascular risk factors diagnosed in the pre-deployment period, of the 697 service members medically evacuated for cardiovascular reasons, more than a third had been diagnosed with hypertension (n=236; 33.9%) or hyperlipidemia (n=241; 34.6%). About 1 in 10 service members had an obesity related diagnosis prior to deployment (n=74, 10.6%). Relatively few service members had been previously diagnosed with diabetes (n=21;  3.0%). More than a quarter of all service members with a CVD-related medical evacuation had been diagnosed with more than one cardiovascular risk factor (n=182; 26.1%).


This analysis found that 697 medical evacuations from CENTCOM related to cardiovascular diagnoses occurred between October 2001 and December 2017. Service members with a CVD-related medical evacuation were more likely to be male and 45 years of age or older. These findings are not surprising because it is well documented that the incidence of CVD is higher in men than women of comparable age.11 Likewise, increasing age is also a well-known, traditional, and non-modifiable risk factor for CVD.12

As documented in a recent MSMR analysis, rates of diagnosed CVD in active component service members are low. During the ten-year period between 2007-2016, less than 1% of active component service members received a CVD diagnosis.13 This low prevalence of CVD may explain, in part, the paucity of referrals identified via DD2795 data in CVD-related medical evacuees in this analysis. Relatively few service members with overt CVD are likely to have undergone pre-deployment screening.

Notably, more than a third of evacuees had modifiable CVD risk factors (hypertension, dyslipidemia) and about 1 in 10 had received a diagnosis of obesity prior to their deployment. A significant limitation of this analysis is the lack of data on medical management or treatment of these risk factors which may have ameliorated these conditions.

This analysis appears to indicate that despite robust pre-deployment screening policies, some service members will present in theater with significant cardiovascular issues. One step that has been taken to mitigate the severity of the consequences for these patients is the deployment of cardiology consultants to the CENTCOM AOR.10

Watts et al. reported on the impact of deploying a dedicated theater cardiology consultant to Bagram Air Field in Afghanistan in an attempt to mitigate morbidity and mortality related to cardiovascular complaints and to increase rates of return to duty. This study reported an 85% return to duty rate for military members and a corresponding 15% evacuation rate for those referred for cardiology evaluations between 2010-2013.10 A similar study conducted in Iraq between 2004–2005 demonstrated an 86% return-to-duty rate (and a 14% evacuation rate) for troops referred to a cardiology consultant for evaluation of cardiac symptoms.9 It is notable that these evacuation rates following cardiology evaluations were remarkably similar during two different time periods and in two different locations. These studies seem to indicate that a certain percentage of deployers will require evacuation for cardiovascular reasons regardless of pre-deployment medical screening processes.

In this analysis, the “cause” of a medical evacuation was estimated from diagnoses that were recorded during hospitalizations or outpatient encounters occurring in fixed medical facilities after evacuation from theater. Therefore, classification of an evacuation as CVD-related relied on a diagnosis given in a fixed medical treatment facility after evacuation. This methodology reflects the standard MSMR approach utilized in previous analyses of the causes of medical evacuations.1-3 These diagnoses may differ from the original diagnoses given in the medical evacuation record as provided by TRA2CES. As a result, the estimates of the frequency of CVD-related medical evacuations might differ from estimates derived from diagnoses recorded in the medical evacuation record.

There are several limitations to this analysis that should be considered when interpreting results. The availability of data on the cardiovascular health status of reserve and guard members is limited. Thus, the estimation of pre-deployment diagnoses of cardiovascular conditions in reserve and guard members is likely significantly underestimated.

Data about waivers for cardiovascular conditions were unavailable for this analysis. These data would have provided useful information on the relationship between waivered cardiovascular conditions and subsequent medical evacuation. Conrath et al. determined that soldiers granted a cardiology/pulmonary waiver were significantly more likely to be medically evacuated while deployed than matched controls not granted a waiver (RR: 1.80; 95% CI: 1.40– 2.30).4 However, the exposure in Conrath and colleagues’ analysis was not limited to cardiovascular conditions (i.e., waivers for pulmonary conditions were also included) and the outcome was not specifically CVD related. Analysis evaluating this specific question could provide useful insights to guide future policy.

Another limitation to this analysis is the lack of data on use of nutritional and sports supplements during deployment. The use of nutritional supplements is well documented in deployed populations, as are adverse effects related to these supplements.14-16 Young, healthy military personnel with no prior history of CVD may present with cardiac symptoms in theater as a result of nutritional supplement use. A report summarizing the experiences of internal medicine physicians at a combat support hospital in Kandahar, Afghanistan documented multiple cases of patients presenting with serious cardiac manifestations after use of 1,3-dimethylamine (DMAA)-containing supplements. These manifestations ranged from chest pain to ST-elevation myocardial infarction requiring medical evacuation.17 DMAA use is now prohibited by the military. However, supplement use continues to be an issue. Increased efforts to educate military members about the risks and benefits of nutritional supplements are warranted and should continue to be a focus of prevention efforts.18

This analysis was also unable to evaluate the presence of several other important cardiovascular risk factors due to the unavailability of accurate individual-level data. The factors include levels of physical activity, diet, and, most importantly, tobacco use. Previous surveys of military personnel have reported that approximately 25% of service members are current cigarette smokers. It is likely that a similar proportion of service members requiring medical evacuation in this analysis were current tobacco users. Analyses conducted in the future will likely benefit from the implementation of the standardized periodic health assessment which collects more comprehensive data on tobacco use and other lifestyle-related cardiovascular risk factors.


1. Armed Forces Health Surveillance Center (AFHSC). Medical evacuations from Afghanistan during Operation Enduring Freedom, active and reserve components, U.S. Armed Forces, 7 October 2001-31 December 2012. MSMR. 2013;20(6):2-8.
2. Armed Forces Health Surveillance Center (AFHSC). Medical evacuations from Operation Iraqi Freedom/Operation New Dawn, active and reserve components, U.S. Armed Forces, 2003-2011. MSMR. 2012;19(2):18–21.
3. Armed Forces Health Surveillance Branch. Update: Medical evacuations, active and reserve components, U.S. Armed Forces, 2017. MSMR. 2018;25(7):17–22.
4. Cronrath CM, Venezia J, Rund TJ, Cho TH, Solana NM, Benincasa JA. Medical Redeployment in Soldiers With and Without Medical Deployment Waivers. Mil Med. 2017;182(3):e1704–e1708.
5. Department of Defense. Instruction 6490.07, Deployment-Limiting Medical Conditions for Service Members and DoD Civilian Employees. February 2010. Documents/DD/issuances/dodi/649007p.pdf. Accessed on 5 December 2018.
6. Assistant Secretary of Defense for Health Affairs. Memorandum: Updated Policy for Preand Post Deployment Health Assessments and Blood Samples. 2001. Accessed on 5 December 2018.
7. Clark LL. Surveillance snapshot: Cardiovascular-related deaths during deployment, U.S. Armed Forces, October 2001–December 2012. MSMR. 2018;25(7):30.
8. Armed Forces Health Surveillance Branch. Morbidity burdens attributable to various illnesses and injuries, deployed active and reserve component service members, U.S. Armed Forces, 2017. MSMR. 2018;25(5):26–31.
9. Sullenberger L, Gentlesk PJ. Cardiovascular disease in a forward military hospital during Opera-tion Iraqi Freedom: a report from deployed cardiologists. Mil Med. 2008;173(2):193–197.
10. Watts JA, Russo FD, Villines TC, et al. Cardiovascular complaints among military members during Operation Enduring Freedom. US Army Med Dep J. 2016 Apr-Sep;(2-16):148–152.
11. Vitale C, Fini M, Speziale G, Chierchia S. Gender differences  in  the  cardiovascular  ef fects of sex hormones. Fundam Clin Pharmacol. 2010;24(6):675–685.
12. Dhingra R, Vasan RS. Age as a risk factor. Med Clin North Am. 2011;96(1):87–91
13. O'Donnell FL, Stahlman S, Oetting AA. Incidence rates of diagnoses of cardiovascular diseases and associated risk factors, active component, U.S. Armed Forces, 2007–2016. MSMR. 2018;25(3):12–18.
14. Paisley RD. Nutritional and sports supplement use among deployed U.S. Army soldiers in a remote, austere combat outpost in eastern Afghanistan. Mil Med. 2015;180(4):391–401.
15. Cassler NM, Sams R, Cripe PA, McGlynn AF, Perry AB, Banks BA. Patterns and perceptions of supplement use by U.S. Marines deployed to Afghanistan. Mil Med. 2013;178(6):659–64.
16. Eliason MJ, Eichner A, Cancio A, Bestervelt L, Adams BD, Deuster PA. Case reports: Death of active duty soldiers following ingestion of dietary supplements containing 1,3-dimethylamylamine (DMAA). Mil Med. 2012;177(12):1455–1459
17. Lee RU, Parrish SC, Saeed O,Fiedler JP. Combat internist: the internal medicine experience in a combat hospital in Afghanistan. Mil Med. 2015;180(1):12–16.
18. Deuster PA. What the SOF community needs to know about dietary supplements. J Spec Oper Med. 2018;18(4):131–136.
ICD-9 and ICD-10 codes used for identification of cardiovascular disease and risk factors

Demographic characteristics of service members with cardiovascular disease-related medical evacuations, October 2001–December 2017

Risk characteristics of service members with cardiovascular disease-related medical evacuations, October 2001-December 2017

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