OUP user menu

Pain among Veterans of Operations Enduring Freedom and Iraqi Freedom

Ronald J. Gironda PhD, Michael E. Clark PhD, Jill P. Massengale ARNP, Robyn L. Walker PhD
DOI: http://dx.doi.org/10.1111/j.1526-4637.2006.00146.x 339-343 First published online: 1 July 2006

ABSTRACT

Objective. Pain is one of the most frequently reported symptoms by veterans returning from recent overseas military actions. The purpose of the current study was to obtain a preliminary estimate of the prevalence and severity of pain among veterans of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF; N = 970). The demographic, etiologic, and diagnostic characteristics of 100 veterans with moderate to severe chronic pain conditions were examined in order to provide a description of this new group of pain patients.

Design. This was a historical cohort study that utilized electronic medical record review for all data collection.

Patients. All registered OEF/OIF veterans seeking treatment at a Southeastern Veterans' Affairs medical center were included in the initial cohort. In order to describe the characteristics of those with clinically significant pain, 100 veterans were randomly sampled from the subset of patients who reported moderate to severe chronic pain intensity during a medical visit (N = 219).

Results. Approximately 47% of veterans whose charts included pain score documentation (N = 793) reported at least a mild level of current pain. Moderate to severe pain intensity was recorded for 28% (N = 219) of those in the initial cohort with pain scores. Diagnoses of musculoskeletal and connective tissue disorders were recorded for 82% of those with chronic conditions (i.e., duration ≥1 month).

Conclusions. The results of this preliminary study suggest that a substantial percentage of OEF/OIF veterans will experience clinically significant pain following their military service.

  • Pain
  • Epidemiology
  • Veterans

Introduction

Pain is one of the most frequently reported symptoms by veterans returning from recent overseas military actions. Epidemiological studies of several Persian Gulf War (PGW) clinical and military registries have consistently found pain symptoms and diagnoses to be among the most prevalent medical conditions reported since the cease-fire in 1991. A recent survey of 15,000 PGW veterans representing all military branches revealed high prevalence rates of headaches (54%), joint pain (45%), back pain (44%), muscle pain (33%), and abdominal pain (23%) [1]. Among individuals enrolled in Department of Veterans' Affairs (VA) and Department of Defense (DOD) PGW clinical registries, the most frequently diagnosed medical conditions are musculoskeletal and connective tissue diseases (25% and 36%, respectively) [2,3]. Factor analyses of all medically unexplained symptoms reported by PGW veterans have repeatedly revealed a distinct factor that was heavily loaded with pain and related somatic symptoms and has been labeled arthro-myo-neuropathy [4], dysesthesia [5], musculoskeletal [6], and somatization [7]. While these symptom clusters have not proven to be unique to PGW-era veterans who were deployed to the theater, those who served in the region have been significantly more likely to report these symptoms and conditions than those who did not [1,5].

Given these data, it is not unreasonable to expect that a significant number of veterans of the current ongoing military operations in Afghanistan and Iraq, Operations Enduring Freedom and Iraqi Freedom (OEF/OIF), will report experiencing pain at some point during or following their service. Unfortunately, there are several factors that may place OEF/OIF veterans at a higher risk than those who served in the PGW. High-explosive blast injuries, gunshot wounds, and injuries resulting from motor vehicle accidents [8], all of which have been associated with persistent pain conditions [9–11], have claimed many more casualties than in the PGW. The extended duration of hostilities in Afghanistan and Iraq coupled with lengthy and repeated deployments for many units has increased exposure to these and other risks such as the typical noncombat injuries incurred during field operations. Potentiating these factors may be the changing demographic composition of US military forces. As a result of the need to deploy large numbers of Reserve and National Guard units, the average age of deployed forces has risen. Additionally, women represent a higher percentage of the troops currently deployed than in any previous war. Both of these characteristics, older age and female gender, have been associated with an increased risk for pain in nonveteran populations [12].

The purpose of the current study was to obtain a preliminary estimate of the prevalence and severity of pain among OEF/OIF veterans seeking care at a large Southeastern VA medical center. The demographic, etiologic, and diagnostic characteristics of those with moderate to severe chronic pain conditions were examined in order to provide a preliminary description of this new group of pain patients. It is hoped that these data will facilitate the implementation of effective strategic planning, resource allocation, and personnel training to ensure the early identification and treatment of chronic pain among veterans of OEF/OIF.

Methods

Participants

A list of all OEF/OIF veterans seeking treatment at a Southeastern VA medical center (N = 970) was generated from the local clinical registry. Examination of the electronic charts revealed that 81.8% of these veterans (N = 793) had a pain intensity numeric rating scale (NRS) score recorded during the course of their first medical contact with the VA healthcare system. Among individuals with a pain score recorded during their first visit, 46.5% (N = 369) reported at least some level of current pain (i.e., pain “now” was ≥1 on a 0–10 NRS), with 59.3% (N = 219) of that subset reporting pain intensity at a level (NRS ≥ 4) considered by VA national policy to be clinically significant [13] and more likely to interfere with functional activities [14,15]. From the pool of those with significant pain (NRS ≥ 4; N = 219), 100 veterans (45.7%) were randomly selected for inclusion in the current study. The entire group of veterans with significant pain was not sampled due to budget and time constraints; however, it is likely that the sample was representative of the local population given its relative size.

Procedure

The clinical registry used to generate the list of OEF/OIF veterans is maintained and updated by local medical center staff. The registry contains basic demographic and service-related data and is primarily used for tracking OEF/OIF enrollment for healthcare services. Veterans were classified as OEF/OIF if they had served in the Afghani or Iraqi theaters from October 2001 to present, and the current cohort included those who were enrolled through December 2004. A group of 100 cases was randomly selected from those with clinically significant pain using statistical software. A record review form, which was developed for a local quality improvement project, was used to extract all of the data reported herein from the electronic medical record. The principal sources of these data were clinical notes generated during visits to primary care and specialty clinics. Data were extracted by the third author who had ongoing clinical, administrative, and research experience with the population. A subset of the cases (25%) and pain variables were selected for interrater reliability analyses, which yielded an interclass correlation coefficient of 0.99 for pain intensity and a kappa of 0.95 for primary pain location. Descriptive statistics were used to summarize the data, and one-way analyses of variance were used to compare subsets of the sample. All procedures were approved by the University of South Florida Institutional Review Board and a VA Research & Development Service committee.

Results

Demographic Characteristics

The demographic characteristics of the sample are summarized in Table 1. As indicated, the age of the returning veterans was relatively high, and a significant minority of the individuals served in National Guard units. Hispanics and African Americans were slightly overrepresented relative to the overall racial distribution of the armed services [16]. The vast majority of the sample served in Iraq (71.4%) or in OIF supporting roles elsewhere in the Persian Gulf region (22.0%).

View this table:
Table 1

Demographic characteristics of sample

VariableStatistic
Age (years)
  M (SD)31.4 (8.47)
  Range19–55
Gender (%)
  Female 7.0
  Male93.0
Race (%)
  African American18.0
  Caucasian60.0
  Hispanic22.0
Service (%)
  Active63.8
  Reserve 6.9
  National Guard29.3
Theater (%)
  Afghanstan 4.4
  Iraq*93.4
  Both 2.2
  • N = 100 for age and gender; N = 82 for race; N = 58 for service; N = 91 for theater.

  • * Includes troops deployed to the Persian Gulf region in support of OIF who were not stationed in Iraq.

  • M = mean; SD = standard deviation; OIF = Operation Iraqi Freedom.

Pain Intensity and Duration

The average pain intensity NRS rating of the 100 veterans in this sample was 6.6 (SD = 1.6, range 4–10). Approximately 57% of the sample reported moderately-severe to severe pain (NRS ≥ 7), suggesting that pain may be significantly interfering with the daily functioning of a substantial minority of OEF/OIF veterans entering the VA healthcare system. In order to assess potential pain intensity differences across service type, participants from National Guard and Reserve units were combined and compared with those who served in standard active-duty units. The two groups did not report significantly different average pain intensities, F(1, 57) = 0.05, n.s.

Due to inconsistencies in documentation across the medical records, pain duration data were unavailable for many subjects (N = 21) and recorded only as “chronic” for others (N = 18). Among those with well-defined duration data, 19.7% (N = 12) reported pain conditions that were of less than 1 month in duration (i.e., acute pain). The mean duration of pain for this group was 5.7 days (SD = 4.8). The mean duration for those who had experienced the condition for at least 1 month (i.e., chronic pain) and had a well-defined estimate recorded in the chart (80.3%, N = 49) was 19.2 months (SD = 22.4). There were no differences in average NRS pain intensity scores among the acute, chronic, and missing data groups, F(2, 97) = 0.02, n.s.

Chronic Pain Characteristics

Among individuals with chronic conditions (N = 67), the most frequent site of primary pain was the back (46.4%), followed by the lower limbs (31.3%), upper limbs (7.5%), neck (6.0%), abdomen (1.6%), and genitals (1.5%). Headache and generalized pain were the primary conditions for 4.5% and 1.5% of the chronic participants, respectively. A substantial majority (81.8%, N = 55) of the chronic pain subsample had diagnoses of musculoskeletal and connective tissue disorders.

Medical records indicated that 35.8% (N = 24) of the chronic pain conditions were attributed to an identifiable injury. The remainder of the records either had no reference to injury at all (10.4%) or indicated that there was no identifiable injury (53.7%). Among those with identifiable injuries, the pain condition was attributed to soft tissue insults (17.2%), falls (12.1%), motor vehicle accidents (3%), and other types of noncombat injury (6%). No gunshot wounds or blast injuries were reported.

Discussion

The results of this preliminary study suggest that a substantial percentage of OEF/OIF veterans experience ongoing or new pain following their military service. Approximately 47% of veterans receiving services at a large Southeastern VA medical center whose charts included pain score documentation reported at least a mild level of current pain. Even if it is assumed that all of those without recorded pain scores did not have any pain at the time of the visit, the percentage of enrollees with pain remains significant at 38%. These figures are consistent with data from several PGW surveys and suggest that, similar to PGW veterans, OEF/OIF veterans will report pain conditions more frequently than other medical conditions. Magnifying the potential impact of this problem is the fact that 28% (219/790) of those with a recorded pain score reported pain intensity in a range that has been empirically demonstrated to be associated with functional interference [14,15] and has been identified by the VA as the threshold for intervention [13].

Although a small percentage of individuals with clinically significant pain in this sample was experiencing an acute condition (i.e., less than 1 month), the vast majority was not. Furthermore, it is probable that a subset of those with acute pain at the time of their visit went on to develop a chronic condition. Among those with chronic conditions, diagnoses of musculoskeletal and connective tissue disorders predominated, once again mirroring the distributions observed among PGW veterans. The majority of these individuals did not attribute their injury to an identifiable cause. It remains to be seen to what extent these pain conditions will be associated with the types of diffuse symptom clusters reported by the subset of PGW veterans who received the controversial diagnosis of Gulf War Syndrome.

Despite the preliminary nature of these data and the inherent limitations of sampling from a single VA catchment area, these estimates foretell the likely pervasiveness of clinically significant pain among veterans returning from OEF/OIF. In fact, there are several factors suggesting that the current figures may underestimate the eventual prevalence of pain in this population. Foremost is the fact that ongoing deployment in both the Afghani and Iraqi theaters continues to place large numbers of troops at risk for a wide array of injuries ranging from the less prevalent, but extremely disabling high-explosive blast-related polytrauma to the more common soft tissue microtrauma incurred during the course of everyday field operations. Additionally, extended deployment may be associated with significant psychosocial stressors that increase the likelihood of the development of chronic pain syndromes, even in the absence of an identifiable injury. Finally, although about 2% of OEF/OIF veterans have suffered combat-related traumatic injuries [17], none of these veterans were represented in the current sample. As these individuals begin to appear in future survey samples, estimates of pain prevalence in OEF/OIF veterans may rise, particularly if the rates of these injuries increase as the conflict persists. Moreover, it is not unreasonable to assume that individuals with polytraumatic injuries will present with particularly complex and difficult-to-treat conditions that result from activation of both central and peripheral mechanisms of pain and are complicated by the psychosocial challenges of adaptation to the significant loss of physical and/or cognitive function.

As early identification and treatment of pain are known to reduce the incidence and severity of chronic pain conditions and therefore to conserve healthcare resources [18], it is hoped that these data will help to stimulate a proactive approach to the problem of pain in this population. A necessary first step in this process is the implementation of procedures for identifying individuals who are experiencing pain or who are at a high risk for developing a pain condition. Treatment algorithms designed to match the patient's degree and type of disability to the most appropriate level and form of intervention should be developed and tested. Those with the most severe problems as well as those at risk for developing such conditions are likely to respond best to immediate participation in a multidisciplinary pain management program. In addition, pain specialists should be integrated into the interdisciplinary teams that care for patients who are recovering from serious combat-related trauma, which is likely to be associated with significant and potentially disabling pain. Adoption of these aggressive strategies may ultimately conserve finite healthcare resources and avert unnecessary suffering by preventing the development and progression of complex chronic pain conditions.

The conclusions that may be drawn from this preliminary retrospective study are limited by the inherent unreliability of medical record data and the method used to extract them, the limited sampling frame that was employed, and the absence of a reliable means of assessing the validity of these data. Although clinical efforts cannot await additional empiric data, it is clear that further investigation will be essential to address the problem of pain in this population most effectively. Larger, more representative epidemiological studies will be needed to provide better description of the extent, nature, and course of pain conditions among these veterans over time following deployment. Complementing these studies should be randomized controlled trials of promising treatments that target pain and its psychosocial consequences among veterans returning from OEF/OIF.

Acknowledgments

This work was supported by a VA RR & D Career Development Award (awarded to the first author), the VA RR & D Merit Review Grant ♯O3283R (awarded to the second author), and the James A. Haley Veterans' Hospital. The authors would like to thank Prado Antolino, M.A., for her careful proofreading and editing.

References

View Abstract