The proportion of women serving in the U.S. military is increasing. Currently, women account for approximately 15% of Active Duty and 19% of Selected Reserve forces (U.S. Department of Defense, Office of the Deputy Assistant Secretary of Defense for Military Community and Family Policy, 2018), and more than 280,000 deployed in support of the conflicts in Iraq and Afghanistan (U.S. Department of Defense, 2013). Although women were previously restricted from ground combat positions and units, many suffered combat-related injuries due to blurred battle lines (e.g., guerilla warfare) (Dye et al., 2016; Karmark, 2016). Furthermore, in 2013, the Direct Ground Combat Definition and Assignment Rule was rescinded, and all combat positions were subsequently opened to women (Karmark, 2016; U.S. Department of Defense, 2013). Because of these policy and enemy tactics changes, servicewomen may be at a greater risk of combat injury and death than in previous wars as they transition to expanded military roles (Armed Forces Health Surveillance Center, 2012; Dye et al., 2016).
At the time of this study, more than 1,000 women were wounded in action, and 168 died while serving in Iraq and Afghanistan (Defense Casualty Analysis System, n.d.). The majority of those wounded were injured by blasts (Dye et al., 2016). These injuries are often complicated by polytrauma, which presents unique challenges in emergency care (Centers for Disease Control and Prevention, 2013). Research on women with combat-related amputations is sparse, likely because of the small number of women with these injuries. A Medical Surveillance Monthly Report (Armed Forces Health Surveillance Center, 2012) counted only 24 servicewomen with deployment-related major limb amputation. Nevertheless, because of the growing number of servicewomen in combat occupations, it may be expected that the number of women with traumatic amputations will increase in future conflicts (Katon & Reiber, 2013).
Studies among women service members and veterans with deployment-related amputations have examined long-term outcomes (Katon & Reiber, 2013; Riviera et al., 2015), but a research gap remains in understanding their immediate outcomes and health care needs. Furthermore, research on sex differences in postamputation acute care and complications is primarily limited to civilians, and findings among civilians with traumatic amputations may not generalize to a military cohort (Edwards et al., 2016). A recent study on upper extremity amputations in civilians found that, although male sex predicted mortality, men and women did not differ in the occurrence of acute major and minor systemic and local complications (Fisher et al., 2018). Another study among civilians found that women with amputations did not differ from men in terms of comorbidities and length of hospital stay but were less likely to be fitted with a prosthetic lower limb than men at discharge (Singh et al., 2008). Previous research has also found that, in general, women civilians and veterans use more health care services than their male counterparts (Bertakis & Azari, 2010; Frayne et al., 2007; Friberg et al., 2016), but little is known about sex differences in postamputation health care utilization. Research on the immediate care and outcomes of servicewomen with combat-related amputations is necessary to obtain clinical knowledge to tailor individualized care and address the specific needs of this group (Randolph et al., 2016).
KEY POINTS
* Complications among women with combat-related amputations were common but not statistically different from those in men.
* The most common complications after amputations in women were heterotopic ossification, anemia, and bacterial wound infections.
* Women recovering from amputations had more acute care bed days but fewer ICU bed days than men.
* Future studies are warranted to inform military and civilian health care providers on the specific needs of women with combat-related injuries.
OBJECTIVE
The objectives of this study were to describe postinjury acute care, complications, and health care utilization among servicewomen with combat-related major limb traumatic amputations and to assess sex differences in these factors using matched-pairs analysis with a group of similarly injured servicemen.
METHODS
Study Sample and Data Sources
This was a retrospective matched-pairs study. The study sample was obtained from the Expeditionary Medical Encounter Database (EMED), maintained by the Naval Health Research Center in San Diego, CA (Galarneau et al., 2007). Data contained in the EMED are extracted from U.S. service members' medical records completed by military providers at treatment facilities in combat theater, close to the point of injury. Injuries are characterized using the Abbreviated Injury Scale (Gennarelli & Wodzin, 2005) and International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes (Commission on Professional Hospital Activities, 1997). Patient records in the EMED are combined with inpatient and outpatient medical information and tactical, operational, personnel, and deployment-related data obtained from other U.S. Department of Defense databases. Combining information from these sources makes a robust clinical picture of each patient available to clinicians and researchers. The study was approved by the institutional review board at the Naval Health Research Center.
The EMED was queried for servicewomen using the Abbreviated Injury Scale traumatic amputation codes for the upper extremities (711000.3, 711001.4, 711002.4, 711012.5, 711003.3, and 711004.2) and lower extremities (811000.3, 811001.4, 811010.5, 811002.4, 811012.5, 811003.3, and 811004.2). Twenty U.S. servicewomen who survived amputations that occurred within 24 hr of a combat-related injury event during Operation Enduring Freedom or Operation Iraqi Freedom were identified for analysis. Injury dates ranged from 2003 to 2012. To compare acute care, complications, and health care utilization by sex, servicemen in the EMED were matched to women in a 1:1 ratio on Abbreviated Injury Scale amputation codes, age (+/-1 year), and Injury Severity Score (ISS; +/-1 point) (Baker et al., 1974). In the case of a complex injury profile, such as a patient who suffered traumatic amputation in addition to open liver laceration or burns, additional injuries were matched as closely as possible to maintain similar injury profiles between the matched pairs.
Measures
Demographic and Injury-Specific Characteristics
Individual demographics and injury-specific characteristics were obtained from the EMED and included age, service branch (Army, Marine Corps, or Navy), occupation (administration and functional support, infantry, service and supply handlers, or other), military operation (Operation Enduring Freedom or Operation Iraqi Freedom), ISS, injury mechanism, and vehicle mount status (mounted or dismounted). The number of deployments and the number of days deployed were collected from the Defense Enrollment Eligibility Reporting System.
Acute Care
Postinjury acute care information was obtained from medical records review and included tourniquet use between the point of injury and the initial treatment facility in combat theater, procoagulant agent (i.e., tranexamic acid or factor VIIa) administration, and massive transfusion at a treatment facility in combat theater. These variables were categorized as "yes" or "no/unknown."
Complications
Medical complications that occurred within 30 days after injury were identified via ICD-9-CM codes from the Military Health System Data Repository and grouped into cerebrovascular, pulmonary, hematological, genitourinary, gastrointestinal, musculoskeletal, and integumentary complications. Heterotopic ossification, specifically, was confirmed by radiology reports and documented if occurring within 1 year after injury in both groups. Patient medical records were reviewed by registered nurses to confirm these complications, and any additional complications identified in the medical records review were added to the patient's clinical profile and included in the analysis. Complications were categorized as "yes" or "no/unknown."
Health Care Utilization
Health care utilization variables included hospitalizations, intensive care unit (ICU) bed days, acute care bed days, and outpatient physical therapy visits. Data for hospitalizations, ICU bed days, and acute care bed days were collected from the Standard Inpatient Data Record in the Military Health System Data Repository during the first year postinjury. Outpatient physical therapy visits were assessed using the Standard Ambulatory Data Record and Comprehensive Ambulatory and Professional Encounter Record in the Military Health System Data Repository. These visits were identified by a Medical Expense Performance Reporting System code for physical therapy clinic services used during the first year postinjury.
Statistical Analysis
Absolute numbers and percentages were calculated for categorical variables. Distributions of amputations by anatomical location were not calculated to maintain patient confidentiality. Means, standard deviations, medians, and ranges were calculated for continuous variables. Categorical variables were compared across the matched pairs using the McNemar test or McNemar-Bowker test, and continuous variables were assessed with the Wilcoxon signed-rank test. An [alpha] level of .05 was used to determine statistical significance. All analyses were completed using SAS Version 9.4 (SAS Institute, Cary, NC).
RESULTS
The study sample included 40 service members (20 women and 20 men) matched on ISS (M = 16.0, SD = 6.3), age (M = 26.0, SD = 5.4), and major limb traumatic amputations that occurred in the immediate 24-hr postinjury period. All amputations were caused by a combat blast-related event. There were 46 amputations, 23 in each sex, as three members in each group suffered bilateral amputations. Thirty-eight of 46 amputations (85%) were to the lower extremities.
The study sample's demographic and injury-specific characteristics are shown by sex in Table 1. All of the injured women served in the Army and were in primarily administrative (n = 6) or service and supply positions (n = 7), whereas men were distributed in the Army (n = 12), Marine Corps (n = 7), and Navy (n = 1), and most served in infantry positions (n = 12). Most women were injured in Operation Iraqi Freedom (n = 15), whereas men were more evenly distributed between Operation Enduring Freedom (n = 9) and Operation Iraqi Freedom (n = 11). The average number of days deployed was lower in women (M = 307.2, SD = 181.5) than in men (M = 380.1, SD = 217.1). Nearly half of all women and men were dismounted at the time of injury. There were no statistically significant differences between the sexes on any demographic or injury-specific variables (ps > .05).
Acute Care
For acute care provided in combat theater, fewer women than men had tourniquets (n = 13 vs. n = 16), procoagulant agents (n = 3 vs. n = 5), and massive transfusion (n = 6 vs. n = 8), but differences were not statistically significant in paired analyses (ps > .05).
Complications
Overall, the average number of postamputation complications was 3.4 for women (SD = 1.6) and 3.3 for men (SD = 1.9). As shown in Table 2, the most common complications among women were heterotopic ossification (n = 17), posthemorrhagic anemias (n = 13), and bacterial wound infections (n = 10). These were also the most frequent complications among men. There were no sex differences in complications in paired analyses (ps > .05).
Health Care Utilization
As shown in Table 3, in the first year postinjury, women had a slightly higher mean number of acute care bed days (M = 49.8, SD = 30.6) than men (M = 46.1, SD = 27.4) but fewer ICU bed days (women: M = 2.6, SD = 4.0; men: M = 4.4, SD = 8.3). Both groups averaged approximately three hospitalizations during the study period. Within 1 year after injury, women (M = 170.2, SD = 121.3) averaged a higher number of outpatient physical therapy visits than men (M = 138.0, SD = 71.7). Overall, differences in health care utilization variables by sex were not statistically significant in paired analyses (ps > .05).
DISCUSSION
This study is one of the first to examine acute care, complications, and health care utilization of servicewomen with combat-related major limb traumatic amputations and to compare these characteristics with servicemen. The primary findings of this study were that postamputation complications among servicewomen were common but comparable with men in matched-pairs analysis. In addition, servicewomen and servicemen did not statistically differ in postamputation acute care or health care utilization measures.
Clinical records completed in combat theater provided information on some acute care and resuscitation measures, such as tourniquet use and procoagulant agent administration. The distribution of these initial treatment measures is similar to findings from a study by Godfrey et al. (2017) on mostly male service members with deployment-related traumatic amputations in the Joint Theater Trauma Registry. Although men and women did not differ on these variables in the present study, there are other treatments not included in the analyses (e.g., types of blood products), and studies on differences regarding additional acute care and resuscitation measures may be warranted.
With the exception of one study that found no differences in heterotopic ossification between military women and men (Potter et al., 2007), the present study was novel in comparing complications after combat-related amputations by sex. No additional research on sex differences in military service members with combat-related amputation was available for comparison at the time of this study, and comparable literature among civilians with traumatic amputation is limited. Our findings are consistent with those of one study in civilians that found no differences between women and men in postamputation complications following upper extremity amputation (Fisher et al., 2018).
The greatest number of complications among women occurred in the form of heterotopic ossification at the amputation site. Previous research has shown that heterotopic ossification is more common among military populations than in civilians (Matsumoto et al., 2014). Clinician review of radiology reports confirmed that 85% of women in the present study developed heterotopic ossification within 1 year postinjury, which is higher than two previous military studies (Melcer et al., 2011; Potter et al., 2007). Melcer et al. (2011) identified heterotopic ossification in 60% of servicemen with combat-related amputation using radiology reports, which corroborated an earlier study by Potter et al. (2007) that found it in 63% of service members with amputations using medical records and radiographs. Both studies used a follow-up period of at least 12 months. The higher proportion of heterotopic ossification in the present analysis may be due to the relatively small sample size of women with combat-related major limb traumatic amputations.
Studies on civilians have reported postamputation wound infections and sepsis among the highest postamputation complications (Belmont et al., 2011; Low et al., 2017). This is highlighted by a previous study utilizing National Surgical Quality Improvement Program data that found wound infection rates of approximately 9% in patients undergoing below-the-knee amputations (Belmont et al., 2011). Bacterial wound infections were much more common in the present study, occurring among 50% of women. These dissimilar findings are not surprising considering that traumatic amputations occurring in combat may be more prone to infection because of the contaminated nature of wounds from the battlefield. Notably, wound infection rates in the present study compared closely with a recent study by Stewart et al. (2019), which investigated factors that may predict infections in extremity wounds incurred in combat. In their study, which comprised servicemen with combat-related traumatic amputations, Stewart et al. found that 47% had a wound infection during their initial hospitalization period.
Comprehensive rehabilitative care is essential for servicewomen and servicemen to optimize outcomes following traumatic limb amputation (Rivera & Pasquina, 2016), ideally using an interdisciplinary approach to individualize care (Parnell & Urton, 2021). Previous research in civilians and veterans demonstrates higher utilization of medical care, especially in women compared with men (Bertakis & Azari, 2010; Frayne et al., 2007; Friberg et al., 2016). In the present study, there were no differences between servicewomen and servicemen in bed days in the first year postinjury. Overall, women averaged nearly three more physical therapy visits per month than men, but the matched-pairs analysis difference was not statistically significant. It is important to note that military service members have full access to comprehensive rehabilitation after injury (Rivera & Pasquina, 2016). The relative equal use of postamputation outpatient physical therapy services in the present study may be due to fewer barriers to care in military than civilian health care systems. Future studies are warranted to investigate sex differences in the type of health care delivered, as well as outcomes occurring after 1 year, including postamputation pain, physical functioning and activity levels, prosthetic use, and dissimilarities in issues that may arise for women and men when returning to the civilian workforce.
The results of this study demonstrate that postamputation complications among servicewomen were common, particularly heterotopic ossification, posthemorrhagic anemias, and bacterial wound infections. For any member with severe traumatic injuries, continued quality care and health promotion are essential for long-term management. Within women veteran groups, health disparities such as smoking and mental health disorders have also been noted (Lehavot et al., 2012). These are added concerns when promoting healthy behaviors in a population with severe trauma and will need lifetime treatment as they enter veteran and civilian health care systems. Patient outcomes can be optimized by engaging service members who sustained amputations in self-care to meet physical and psychosocial needs early in the rehabilitative process (Schreiber, 2017).
LIMITATIONS
There are limitations that warrant mention. First, the total number of servicewomen with combat-related amputations from Operation Enduring Freedom and Operation Iraqi Freedom is low, which yielded a small sample size. We used a matched-pairs design to mitigate the effects of this limitation. Second, the use of ICD-9-CM codes to identify postamputation complications may not elucidate important clinical subgroups (Al-Rawajfah et al., 2015). Finally, documentation in a combat environment may be incomplete due to the high operational tempo and need to provide immediate, lifesaving care. As such, some data points from the point of injury and military facilities in combat theater may be underreported, but we expect this would be nondifferential between the groups.
CONCLUSIONS
In this study, postamputation care and complications among servicewomen were comparable with those in servicemen. The findings highlight that servicewomen with combat-related amputations frequently experienced postinjury complications. This information will be useful in managing these injuries in military health care settings and civilian facilities in the continuum of care. Although it is encouraging to identify little or no differences between the sexes in postamputation care and complications, it is important to continue to examine the specific health care needs of injured military women as future conflicts will see greater numbers serving in combat occupations.
Acknowledgments
This work was supported by the Extremity Trauma and Amputation Center of Excellence under Work Unit No. N1333. The authors thank Patricia Saucedo and Melanie Adams for their assistance with injury coding, medical records review, and quality assurance.
REFERENCES