Journal of Asthma
ISSN: 0277-0903 (Print) 1532-4303 (Online) Journal homepage: http://www.tandfonline.com/loi/ijas20
The impact of combat deployment on asthma diagnosis and severity Sally P. DelVecchio DO, Jacob F. Collen MD, Lisa L. Zacher MD & Michael J. Morris MD To cite this article: Sally P. DelVecchio DO, Jacob F. Collen MD, Lisa L. Zacher MD & Michael J. Morris MD (2015) The impact of combat deployment on asthma diagnosis and severity, Journal of Asthma, 52:4, 363-369 To link to this article: http://dx.doi.org/10.3109/02770903.2014.973502
Accepted author version posted online: 07 Oct 2014. Published online: 22 Oct 2014. Submit your article to this journal
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Date: 15 November 2015, At: 00:17
http://informahealthcare.com/jas ISSN: 0277-0903 (print), 1532-4303 (electronic) J Asthma, 2015; 52(4): 363–369 ! 2014 Informa Healthcare USA, Inc. DOI: 10.3109/02770903.2014.973502
RISK FACTORS FOR ASTHMA
The impact of combat deployment on asthma diagnosis and severity Sally P. DelVecchio, DO1, Jacob F. Collen, MD2, Lisa L. Zacher, MD3,4, and Michael J. Morris, MD2 Pulmonary/Critical Care Service, Womack Army Medical Center, Fort Bragg, NC, USA, 2Pulmonary/Critical Care Service, San Antonio Army Medical Center, Fort Sam Houston, TX, USA, 3Department of Medicine, Orlando Veterans’ Administration Medical Center, Orlando, FL, USA, and 4College of Medicine, University of Central Florida, Orlando, FL, USA
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Objectives: Environmental exposures during military deployments to Iraq and Afghanistan may lead to higher rates of respiratory complaints and diagnoses. This study investigates whether there is a relationship between rates of asthma diagnosis and severity associated with military deployment. Methods: Retrospective review of active duty Army personnel underwent fitness for duty evaluation (Medical Evaluation Board) for asthma. The electronic medical record was reviewed for onset of diagnosis (pre- or post-deployment), disease severity, screening spirometry, bronchodilator response and bronchoprovocation testing. We compared patients with and without a history of combat deployment to Operations Iraqi Freedom/Enduring Freedom. Results: Four hundred consecutive Army personnel with a clinical diagnosis of asthma were evaluated. Equal numbers of patients had deployed (48.5%) versus never deployed (51.5%). Of those who deployed, 98 (24.5%) were diagnosed post-deployment. The diagnosis of asthma was objectively confirmed in 74.8% of patients by obstructive screening spirometry, bronchodilator response, and/or methacholine challenge testing. There were no significant differences in spirometry between deployers and non-deployers or based on pre- and postdeployment diagnosis. Similarly, asthma severity classification did not differ between deployed and non-deployed service members, or by pre- and post-deployment diagnosis status. Conclusions: Among active duty military personnel with career limiting asthma, there is no significant relationship between rates of diagnosis or severity based on history of deployment to Southwest Asia.
Asthma, deployment, military personnel, pulmonary function testing
Introduction Combat deployments to Iraq and Afghanistan in Southwest Asia (SWA) have coincided with environmental exposures to inhaled particulate matter (PM) and increased respiratory symptoms among active duty military personnel [1,2]. Prior research has addressed airway symptoms and respiratory illness resulting from oil fire exposure in the first Gulf War [3,4]. However, current active duty service members (ADSM) are mobilized to SWA for longer periods of time and often for multiple deployments, raising concern that increased exposures may result in a rising burden of acute and chronic respiratory disease. Surveillance data by the United States Army Public Health Command demonstrated higher levels of PM secondary to dust, frequent sand storms, burn pits, explosives and vehicle exhaust among others. Additionally, non-specific upper and lower respiratory symptoms such as rhinorrhea, wheezing, cough and dyspnea have increased significantly based on survey data during the past decade of war[5]. Correspondence: Jacob F. Collen, Pulmonary/Critical Care Service (MCHE-MDP), San Antonio Military Medical Center, 3551 Roger Brooke Drive, JBSA Fort Sam Houston, TX 78234, USA. E-mail: [email protected]
History Received 6 September 2014 Revised 23 September 2014 Accepted 1 October 2014 Published online 22 October 2014
In susceptible individuals, prolonged exposure and inhalation of dust particles may result in increased pulmonary symptoms and/or result in diagnoses of respiratory disease, such as reactive airways disease, asthma or other airway disorders. However, there is little direct evidence that pulmonary toxicity explains these symptoms or clearly links them to deployment-related exposures [6]. A cluster of cases of acute eosinophilic pneumonia from Iraq/Afghanistan has been described which may have been linked to new onset or increased tobacco use in theater [7,8]. Another cohort of soldiers with histologic evidence of constrictive bronchiolitis has been published; however, these changes were of unclear clinical significance, given the paucity of abnormal physiologic and imaging findings [9]. These studies do not address the vast majority of cases of ADSM with respiratory symptoms of variable severity. The majority of literature on deployment-related respiratory exposures and resultant respiratory symptoms indicates a possible relationship with asthma and reactive airways symptoms [3,5]. Asthma is a relatively common condition in ADSM, despite the diagnosis limiting entrance into the military, and prior research indicates that a significant portion of new recruits are under diagnosed with asthma [10]. In addition, recent changes in medical guidelines for retention of
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military personnel allow soldiers with well-controlled asthma to remain in military service [11]. This potentially increases the pool of ADSM with compromised respiratory status prior to deployment. One study identified 5% of deploying service members with pre-existing asthma. Survey data from this study indicated a significant rise in respiratory symptoms among both asthmatics and non-asthmatics, and among asthmatics, an increase in healthcare utilization and symptoms among those with poor disease control at baseline [12]. A retrospective review of several thousand Veterans’ Administration (VA) medical records noted higher rates of ‘‘new-onset’’ asthma in deployed military personnel between 2004 and 2007 compared to non-deployed personnel stationed in the United States (6.6 versus 4.3%) [13]. Like much of the literature on this topic, these studies were limited by a paucity or lack of spirometry. Given that asthmatic symptoms are commonly reported post-deployment, the purpose of our study was to review medical records of ADSM diagnosed with asthma and determine if there is a significant relationship between asthma diagnoses and disease severity based on deployment status. Active duty personnel undergoing a Medical Evaluation Board (MEB) have chronic asthmatic symptoms felt to be incompatible with continued military service and may be referred to pulmonary specialists for evaluation.
Methods This study was conducted as a retrospective review of Department of Defense (DoD) electronic medical records after obtaining written approval from our hospital’s Institutional Review Board (IRB # C.2010.126 d). The MEB database was queried to identify ADSM with an International Classification of Disease, 9th edition (ICD-9) code for asthma (493.xx) for five consecutive years from 2005 to 2009. Patient records were abstracted from the database for ADSM who were undergoing an MEB (fitness for duty evaluation) for asthma. These patients referred to the MEB program had symptoms severe enough to limit their ability to continue active duty service in the military. Medical records that lacked any medical encounters or objective clinical information about the diagnosis of asthma were excluded from further analysis. Deployment information for Operations Iraqi Freedom/Enduring Freedom for individuals with qualifying medical records was obtained from the Armed Forces Health Surveillance Center. After the initial query was conducted and qualifying subjects with an asthma diagnosis were identified, consecutive electronic medical records were reviewed to obtain the following information: (1) patient demographics; (2) date of initial diagnosis; (3) asthma diagnosis prior to military service; (4) smoking history; (5) pulmonary function testing (PFT) results to include forced expiratory volume in one second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio (actual and predicted), post-bronchodilator FEV1; (6) methacholine challenge test (MCT) results; and (7) asthma severity. Spirometry was reviewed to determine if patients underwent a standard forced expiratory maneuver from maximal inhalation to maximal exhalation to record the FEV1 and FVC in accordance with American Thoracic Society standards for
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spirometry [14]. Reference values were taken from National Health and Nutrition Examination Survey III (NHANES III) equations [15]. Obstruction was defined as an FEV1/FVC ratio below the 5th percentile predicted (lower limits of normal based on the NHANES III reference equations in accordance with the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines) [15,16]. Patients were given two puffs of a short-acting beta-agonist to measure FEV1 improvement post-bronchodilator. Methacholine challenge testing was typically administered at the following concentrations: normal saline, 0.0625, 0.25, 1.0, 4, 8, and 16 mg/ml. Testing was repeated for all methacholine concentrations until maximal concentration or a 20% drop in the FEV1. The bronchoprovocation test was considered positive with 20% decrease in FEV1 at a dose of 4 mg/ml or less [17]. The diagnosis of asthma was based on: (1) FEV1/FVC ratio below the 5th percentile of the normal distribution (lower limit of normal) with evidence of airway obstruction on spirometry; (2) a bronchodilator response412% or 200 ml for FEV1 representing airflow variability; or (3) MCT with a greater than 20% decline in the FEV1 indicating bronchial hyperresponsiveness [14,15,17]. Patients were classified into three groups based on deployment history to Iraq (Operation Iraqi Freedom) and/ or Afghanistan (Operation Enduring Freedom). The timing of the diagnosis of asthma (pre-or post-deployment) was noted and patients were categorized as: (1) never deployed, (2) diagnosis pre-deployment or (3) diagnosis post-deployment. Further comparison was based on spirometry values (FEV1, FVC and FEV1/FVC) and asthma severity. Outcomes The primary outcomes of our study were whether or not rate of diagnosis and severity of asthma differed based on deployment status. Secondary outcomes assessed whether differences existed between the comparison groups with regards to spirometric values. Statistical analysis Statistical analysis was performed using commercially available software (R Version 3.0.2). Data are expressed as mean ± SD, unless otherwise noted. Normality was tested for the demographic and PFT variables, and a Student’s t test or Mann–Whitney U test was used as appropriate between the two groups. Specific comparisons were made for age, tobacco use, FEV1 (% predicted), FEV1 post-bronchodilator (% predicted) and percent change, FVC (% predicted), FEV1/FVC ratio and severity of disease. p Values less than 0.05 were considered statistically significant.
Results Four hundred consecutive patients with asthma and complete medical records were included in the final analysis after review of 1867 patient files in the Department of the Army’s MEB database between the years 2005 and 2009. The majority of patients were male (n ¼ 291, 73%). Based on Armed Forces deployment data, 194 (48.5%) individuals had deployed to SWA on one or more occasion for greater than
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DOI: 10.3109/02770903.2014.973502
60 days (Figure 1). The timing of asthma diagnosis was split equally between pre-deployment (n ¼ 93) and postdeployment (n ¼ 101). Non-deployers were younger than deployers (25.4 ± 7.0 years versus 27.1 ± 6.4 years, p ¼ 0.01), but there was no significant age difference between those diagnosed pre- and post-deployment. One quarter of the cohort smoked cigarettes and although there was a slight trend towards more smokers among the group that had deployed, there was no difference between those with a pre- or postdeployment diagnosis (Table 1). Among those who had deployed, the duration of deployment was longer for those with a pre-deployment diagnosis (373 ± 185 days) compared to those with a post-deployment diagnosis (329 ± 185). Pulmonary function test results were available for 355 (84%) of the cohort, equally split between deployed and nondeployed patients, and those with pre- and post-deployment diagnosis (Table 2). Comparison between subgroups demonstrated that the FEV1/FVC ratio was decreased in nondeployers compared to deployers. Although this difference was statistically significant, it did not appear to be clinically significant. Similarly, there was a trend towards a lower FEV1/FVC ratio in those with pre-deployment compared to post-deployment diagnosis, also too small a difference likely to be of clinical significance. There were no other significant differences in spirometry between groups. Testing for bronchodilator responsiveness was performed in 227 (57%)
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patients and 119 (30%) had a positive test (increase of 12% and 200 ml in FEV1) (Table 2). A diagnosis of asthma based on objective testing was identified in 74.8% of the entire cohort. Similar percentages (76.2 and 73.2%) were noted for all patients in the nondeployed and deployed groups, respectively (Figure 2). Fixed obstruction on spirometry was evident in 43.0% of the cohort with similar values for non-deployers and deployers (42.2 versus 44.3%). A similar range of test results (non-deployers versus deployers) was seen for post-BD response (30.1 versus 29.4%, respectively) and MCT (32.5–30.4%). When those asthma patients without any documented studies were excluded, 79.1% of the overall group met diagnostic criteria for asthma. Nearly half (47.9%) had fixed obstruction on spirometry, 46.9% responded to a bronchodilator and 94.7% had a reactive MCT when tested. The majority of patients were diagnosed with mild persistent (39%) or moderate persistent (44%) asthma. Seven percent had severe persistent asthma and 10% had exercise-induced asthma. There was no correlation between disease severity and deployment status (Figure 3). Nondeployers and deployers had similar percentages for mild asthma (34 versus 43%), moderate asthma (45 versus 41%) and severe asthma (8 versus 6%). Among those who had deployed, similar percentages for disease severity were present based on pre- or post-deployment asthma diagnosis.
Figure 1. Deployment history. Distribution of active duty service members with asthma based on deployment history and whether asthma diagnosis was established pre- or post-deployment.
MEB for Asthma (n = 400)
Deployed n = 194 (48.5%)
Asthma Diagnosis PreDeployment n = 93 (23.3%)
Non-Deployed n = 206 (51.5%)
Asthma Diagnosis PostDeployment n = 101 (25.2%)
Table 1. Clinical and demographic variables. Clinical and demographic variables for subjects based on deployment and non-deployment classification.
N Male (%) Age (years) Deployment duration (days) Smoking history
Overall cohort
Non-deployers
Deployers
p Value
Pre-deployment diagnosis
Post-deployment diagnosis
p Value
400 291 (72.8%) 26.2 ± 6.8 N/A 96 (24%)
206 135 (65.5%) 25.4 ± 7.0 N/A 41 (25%)
194 156 (80.4%) 27.1 ± 6.4 350 ± 186 55 (28%)
0.44 0.10 0.01 N/A 0.06
93 70 (73.5%) 26.8 ± 6.7 373 ± 185 25 (27%)
101 86 (85.1%) 27.3 ± 6.2 329 ± 185 30 (30%)
0.48 0.09 0.30 0.05 0.45
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Table 2. Pulmonary function testing.
N (%) FEV1 (% predicted) FVC (% predicted) FEV1/FVC (predicted) FEV1/FVC (actual) Post-BD FEV1 (% predicted)
Overall cohort
Non-deployers
Deployers
p Value
Pre-deployment diagnosis
Post-deployment diagnosis
p Value
337 (84%) 78.6 ± 17.5 87.5 ± 16.9 83.5 ± 6.1 75.1 ± 11.1 85.0 ± 16.7
173 (84%) 77.9 ± 18.0 88.0 ± 17.6 84.2 ± 4.7 74.6 ± 12.0 84.6 ± 18.1
169 (87%) 79.2 ± 17.1 87.1 ± 16.1 82.8 ± 7.2 75.6 ± 10.1 85.3 ± 15.4
– 0.51 0.63 – 0.05 0.76
82 (88%) 77.9 ± 18.7 86.0 ± 17.4 83.7 ± 3.6 75.2 ± 10.0 84.0 ± 15.7
87 (86%) 80.5 ± 15.4 88.1 ± 15.0 82.0 ± 9.5 76.1 ± 10.2 86.6 ± 15.1
– 0.17 0.21 – 0.07 0.18
Comparison of pulmonary function testing values for non-deployer and deployer groups with additional comparison within the deployer group based on whether the diagnosis of asthma was made pre- or post-deployment. FEV1 forced expiratory volume at one second; FVC forced vital capacity; BD bronchodilator
90% ALL
Non-Deploy
Deploy
Pre-Deploy
Post-Deploy
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80%
75% 76%
73%
70%
76% 70%
60% 50%
50% 43% 42% 44%
40%
40% 30% 30% 29%
30%
32% 33%
32%
30% 31% 30%
27%
20% 10% 0% Obstrucon
Post-BD
MCT
Any
Figure 2. Diagnostic criteria for asthma. Percentage of all patients with positive studies. Obstruction–reduction in FEV1/FVC ratio below the lower limits of normal or 5th percentile of the predicted value (based on the NHANES III reference equations in accordance with the 2005 ATS/ERS guidelines); Post-BD – 12% increase in FEV1 post-bronchodilator; MCT – reactive methacholine challenge test.
Discussion Among a cohort of patients with duty limiting asthma, deployment to SWA was not related to the rate of diagnosis or disease severity. The majority (75%) of ADSM in this cohort were diagnosed with asthma without having ever deployed or prior to SWA deployment. A smaller percentage (25%) was diagnosed post-deployment. Among those who deployed, there was no difference in clinical severity of disease or spirometry based on diagnosis pre- or post-deployment. In fact, non-deployers demonstrated a slightly lower (although statistically significant) FEV1/FVC ratio, and there was a trend towards a lower ratio in patients with a pre-deployment diagnosis. It was not determined what other differences may exist between these groups, or if post-deployment asthmatics represent a separate phenotype from those within the military that lack deployment exposures, or asthmatics without military service.
There is ongoing concern surrounding development of respiratory disease in ADSM following deployment to SWA. The most recently published study on this topic by Morris et al. prospectively evaluated ADSM 6 months postdeployment with a comprehensive evaluation that included spirometry, chest imaging, MCT and bronchoscopy. This study demonstrated that the majority of established respiratory diagnoses (40%) comprised airway hyperreactivity (AHR) syndromes, predominantly asthma [18]. The specific etiology of AHR was not established but could be related to exacerbation of pre-existing disease or new disease from PM exposure. Prior studies have demonstrated that asthma may be under diagnosed among new recruits [10] and may be increased in those persons with duties that entail a greater risk of environmental exposure to allergens and activity [19]. The current literature on asthma in relation to deployment has
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60% Non-Deployed
Deployed
Pre-Deploy Dx
Post-Deploy Dx
49%
50%
40%
40%
45%
45%
43%
41%
39%
34%
30%
20% 12% 8%
10%
8% 6%
7%
6%
7% 3%
0%
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Mild
Moderate
Severe
Exercise
Figure 3. Asthma severity. (mild, moderate, severe, exercise-induced) based on the percentage of total and categorized by deployment history (nondeployed, deployed) and whether the diagnosis of asthma was established pre- or post-deployment. There were no significant differences in the distribution of cases between deployed and non-deployed providers (exercise-induced, p ¼ 0.12; mild, p ¼ 0.96; moderate, p ¼ 0.15; severe, p ¼ 0.65). Nor were there any significant differences in the distribution of cases based on whether the diagnosis was established pre- or post-deployment (exerciseinduced, p ¼ 0.69; mild, p ¼ 0.31; moderate, p ¼ 0.44; severe, p ¼ 1.00).
demonstrated an increased rate of diagnosis post-deployment; however, these studies have been based primarily on survey results, or studies with limited spirometric data that relied on a clinical diagnosis. Szema and colleagues evaluated veterans’ medical records from their region in the northeast United States and separated them into groups based on deployment history. They found a higher rate of asthma diagnosis among those who had deployed (6.3 versus 4.4%), with an increase in symptoms leading to clinical encounters requiring spirometry [13,20]. A minority of patients in these studies had spirometry performed, and symptoms and diagnoses were based on a mix of primary care encounters rather than by a documented subspecialty referral to a pulmonologist. Roop et al. evaluated the impact of deployment on asthmatic and non-asthmatic subjects in a post-deployment survey and found that respiratory symptoms (cough, wheezing, sputum production, chest pain/tightness and allergic symptoms) were increased in both groups, but that the majority of symptoms and healthcare utilization in the subgroup with asthma occurred among those with poor baseline control [12]. Their study also found a high rate of smoking, increasing cigarette use during deployment and significantly associated with symptoms in both groups, notably more so in the subgroup with poor baseline asthma control. Recent studies of deployed military personnel have demonstrated that although respiratory complaints increase after deployment, they are not clearly linked to deploymentrelated environmental exposures or do not correlate with increased diagnosis rates or measures of healthcare utilization. An investigation by the Army Public Health Command found a significant rise in respiratory complaints and medical encounters post-deployment, which was not significantly related to the number of deployments or deployment duration [21]. Baird et al. also evaluated the impact of the 2003 Al-Mishraq sulfur plant fire to nearby service members.
Subjective respiratory complaints worsened among those post-deployment, as did clinical encounters to evaluate respiratory complaints, and overall estimation of health quality was worse among a quarter of respondents. There was not a corresponding increase in encounters for chronic respiratory disorders such as asthma or chronic obstructive pulmonary disease among those subjects with documented fume exposure in comparison to a general pool of respondents [22]. The Millennium Cohort Study is a longitudinal survey study conducted by the Naval Research Center evaluating the relationship between respiratory complaints and disease with deployment. Their ongoing study has identified an increase in respiratory complaints in deployed compared to never deployed personnel (14 versus10%), with no difference in the diagnosis of asthma (1%) or chronic bronchitis (1%). Additionally, significant relationships to diagnosed lung disease are lacking based on proximity to known burn-pit exposures in Iraq and inconsistently related to exposure duration/deployment time [5,6]. Limitations As a retrospective review, this study is subject to selection bias although we purposely selected asthma patients whose disease limited their ability to continue active duty service. As such, one would expect a more chronic course and detailed evaluation with documentation of spirometric abnormalities. Despite the use of this selected population, we identified 30% of the cohort without objective documentation of AHR, which suggests only a clinical diagnosis for asthma. We cannot be sure these patients did not have other evidence of asthma not available for review. Inpatient medical records were not reviewed nor were other types of physiologic testing such as cardiopulmonary exercise testing, plethysmography or impulse oscillometry. Conversely, these patients may have been misdiagnosed and had other pulmonary disorders
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(COPD, vocal cord dysfunction) depending on the extent of the evaluation. We cannot also exclude the possibility that parenchymal lung disease may have impacted the patient’s evaluation. Chest imaging with plain film radiographs and/or chest CT is routine for patients undergoing a medical evaluation board for pulmonary disease and is unlikely to have changed our results. Finally, the active duty population studied is unique and our findings may not apply to a National Guard, Reserve or VA population. Dyspnea among young and otherwise healthy members of the military can be challenging due to several potential confounders including comorbid illness (sleep disorders, psychiatric disease), tobacco use, symptoms that are disproportionate to objective test results, obesity, deconditioning and malingering [18,23]. Although our study did not find a clear association with cigarette use, previous research has cited higher rates of smoking, especially during deployment. Comorbid psychiatric disease and poor quality sleep can lead to fatigue and daytime sleepiness which can impact performance (such as 2-mile physical fitness run times) and perception of symptoms. Finally, obstructive lung disease such as COPD can evolve over time, and our results may be limited by lack of long-term data. Research addressing respiratory complaints in the deployed military population is ongoing. In addition to the confounders listed above, most deployment research is limited by a lack of both pre- and post-deployment spirometry. Recommendations have been made to perform screening in all deployers [24–26]. Unfortunately, performing screening spirometry for all deployers, and follow-up subspecialty referral and testing based on these results is likely cost-prohibitive and limited by subspecialty availability. An unpublished costanalysis by the military calculated that widespread screening spirometry alone for all DoD personnel would be in the tens of millions of dollars, which does not account for additional testing and referrals that would be generated by abnormal initial screening results [27]. An ongoing study conducted at Fort Hood has enrolled 1500 deploying Army personnel and performed pre-deployment spirometry [28]. Preliminary results have demonstrated pulmonary issues such as smoking (18%), persistent dyspnea (3.5%), inhaled medication use (3.1%), failed PT testing (23.4%) and increased body mass index above 30 mg/m2 in 1.9% of the deploying soldiers. Baseline spirometry showed an obstructive ventilatory defect in 8.7% of participants prior to deployment.
Conclusion Deployment-related environmental exposures have an unclear relationship to chronic respiratory disease. Whether such exposures lead to clinical disease, and what the culprit exposures are remains undetermined. In our population of patients with a diagnosis of asthma prompting a fitness for duty evaluation, we did not establish a relationship to SWA deployment. This may indicate that deployment-related lung conditions are subtle and may require a careful evaluation over time to determine the long-term impact on the development of respiratory disease. Furthermore, patients with suspected asthma should undergo adequate testing to meet the established objective criteria for disease. The increase in
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reported respiratory complaints following SWA deployment mandates that the ADSM receive comprehensive medical care, to include pulmonary specialty evaluations when appropriate. As a single evaluation may not reveal evidence of airway hyperreactivity, these patients should be followed longitudinally.
Acknowledgements Dr. Michael Morris is the guarantor for the accuracy and integrity of the data and results presented in this manuscript. Dr. Michael Morris participated in study design, data interpretation, and manuscript writing and editing. Dr. Sally DelVecchio participated in study design, performed all data collection, data interpretation, and the majority of manuscript writing and editing. Dr. Jacob Collen participated in data interpretation, manuscript writing and editing. Dr. Lisa Zacher participated in study design and data interpretation. Dr. Roy Haas, PhD, assisted in performing statistical analysis.
Declaration of interest The opinions in this essay do not constitute endorsement by San Antonio Army Medical Center, the U.S. Army Medical Department, the U.S. Army Office of the Surgeon General, the Department of the Army, Department of Defense, or the U.S. Government of the information contained therein. Dr. Morris is a paid speaker for SpirivaÕ by BoehringerIngelheim. The other authors have no financial interests to disclose. None of the authors have any relevant conflicts of interest to disclose. This study was not supported by any funding or financial sponsorship. The authors alone are responsible for the content and writing of the paper.
References 1. Abraham JH, Baird CP. A case-crossover study of ambient particulate matter and cardiovascular and respiratory medical encounters among US military personnel deployed to southwest Asia. J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 733–739. 2. Weese CB, Abraham JH. Potential health implications associated with particulate matter exposure in deployed settings in southwest Asia. Inhal Toxicol 2009;21:291–296. 3. Lange JL, Schwartz DA, Doebbeling BN, et al. Exposures to the Kuwait oil fires and their association with asthma and bronchitis among gulf war veterans. Environ Health Perspect 2002;110: 1141–1146. 4. Smith TC, Heller JM, Hooper TI, et al. Are Gulf War veterans experiencing illness due to exposure to smoke from Kuwaiti oil well fires? Examination of Department of Defense hospitalization data. Am J Epidemiol 2002;155:908–917. 5. Smith B, Wong CA, Smith TC, et al. Newly reported respiratory symptoms and conditions among military personnel deployed to Iraq and Afghanistan: a prospective population–based study. Am J Epidemiol 2009;170:1433–1442. 6. Smith B, Wong CA, Boyko EJ, et al. The effects of exposure to documented open-air burn pits on respiratory health among deployers of the Millennium Cohort Study. J Occup Environ Med/Am Coll Occup Environ Med 2012;54:708–716. 7. Sine C, Allan P, Haynes R, Scoville S, Shuping E, Hultman A, et al. Case series of 44 patients with idiopathic acute eosinophilic pneumonia in the deployed military setting. Chest 2011;140: 675A–675A(Meeting Abstract). 8. Shorr AF, Scoville SL, Cersovsky SB, et al. Acute eosinophilic pneumonia among US Military personnel deployed in or near Iraq. JAMA 2004;292:2997–3005.
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Downloaded by [New York University] at 00:17 15 November 2015
DOI: 10.3109/02770903.2014.973502
9. King MS, Eisenberg R, Newman JH, et al. Constrictive bronchiolitis in soldiers returning from Iraq and Afghanistan. New Engl J Med 2011;365:222–230. 10. Nish WA, Schwietz LA. Underdiagnosis of asthma in young adults presenting for USAF basic training. Ann Allergy 1992;69:239–242. 11. Army Regulation 40–501. Standards of medical fitness. Washington, DC: Department of the Army; 2002: p. 27. 12. Roop SA, Niven AS, Calvin BE, et al. The prevalence and impact of respiratory symptoms in asthmatics and nonasthmatics during deployment. Military Med 2007;172:1264–1269. 13. Szema AM, Peters MC, Weissinger KM, et al. New-onset asthma among soldiers serving in Iraq and Afghanistan. Allergy Asthma Proc 2010;31:67–71. 14. Miller MR, Hankinson J, Brusasco V, et al. Standardisation of spirometry. Eur Respir J 2005;26:319–338. 15. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med 1999;159:179–187. 16. Pellegrino R, Viegi G, Brusasco V, et al. Interpretative strategies for lung function tests. Eur Respir J 2005;26:948–968. 17. Crapo RO, Casaburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing-1999. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, July 1999. Am J Respir Crit Care Med 2000;161:309–329. 18. Morris MJ, Dodson DW, Lucero PF, et al. Study of active duty military for pulmonary disease related to environmental deployment exposures (STAMPEDE). Am J Respir Crit Care Med 2014. doi: 10.1164/rccm.201402–0372OC[published Online First: Epub Date]j. 19. Katz I, Moshe S, Sosna J, et al. The occurrence, recrudescence, and worsening of asthma in a population of young adults: impact of varying types of occupation. Chest 1999;116:614–618. 20. Szema AM, Salihi W, Savary K, et al. Respiratory symptoms necessitating spirometry among soldiers with Iraq/Afghanistan war
21.
22.
23.
24.
25. 26.
27.
28.
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lung injury. J Occup Environ Med/Am Coll Occup Environ Med 2011;53:961–965. Abraham JH, DeBakey SF, Reid L, et al. Does deployment to Iraq and Afghanistan affect respiratory health of US military personnel? J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 740–745. Baird CP, DeBakey S, Reid L, et al. Respiratory health status of US Army personnel potentially exposed to smoke from 2003 Al-Mishraq Sulfur Plant fire. J Occup Environ Med/Am Coll Occup Environ Med 2012;54:717–723. Morris MJ, Grbach VX, Deal LE, et al. Evaluation of exertional dyspnea in the active duty patient: the diagnostic approach and the utility of clinical testing. Military Med 2002; 167:281–288. Rose C, Abraham J, Harkins D, et al. Overview and recommendations for medical screening and diagnostic evaluation for postdeployment lung disease in returning US warfighters. J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 746–751. Rose CS. Military service and lung disease. Clin Chest Med 2012; 33:705–714. Zacher LL, Browning R, Bisnett T, et al. Clarifications from representatives of the Department of Defense regarding the article ‘‘Recommendations for medical screening and diagnostic evaluation for postdeployment lung disease in returning US warfighters’’. J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 760–761. Morris MJ, Eschenbacher WL, McCannon CE. Workshop D: recommendation for surveillance spirometry in military personnel. Deployment-related airborne hazards. Washington, DC: Borden Institute; 2013 (in-press). Skabelund A, Morris M. Baseline symptoms and pulmonary function of military personnel prior to deployment. Chest 2013; 144:480A–480A.
ISSN: 0277-0903 (Print) 1532-4303 (Online) Journal homepage: http://www.tandfonline.com/loi/ijas20
The impact of combat deployment on asthma diagnosis and severity Sally P. DelVecchio DO, Jacob F. Collen MD, Lisa L. Zacher MD & Michael J. Morris MD To cite this article: Sally P. DelVecchio DO, Jacob F. Collen MD, Lisa L. Zacher MD & Michael J. Morris MD (2015) The impact of combat deployment on asthma diagnosis and severity, Journal of Asthma, 52:4, 363-369 To link to this article: http://dx.doi.org/10.3109/02770903.2014.973502
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Date: 15 November 2015, At: 00:17
http://informahealthcare.com/jas ISSN: 0277-0903 (print), 1532-4303 (electronic) J Asthma, 2015; 52(4): 363–369 ! 2014 Informa Healthcare USA, Inc. DOI: 10.3109/02770903.2014.973502
RISK FACTORS FOR ASTHMA
The impact of combat deployment on asthma diagnosis and severity Sally P. DelVecchio, DO1, Jacob F. Collen, MD2, Lisa L. Zacher, MD3,4, and Michael J. Morris, MD2 Pulmonary/Critical Care Service, Womack Army Medical Center, Fort Bragg, NC, USA, 2Pulmonary/Critical Care Service, San Antonio Army Medical Center, Fort Sam Houston, TX, USA, 3Department of Medicine, Orlando Veterans’ Administration Medical Center, Orlando, FL, USA, and 4College of Medicine, University of Central Florida, Orlando, FL, USA
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Abstract
Keywords
Objectives: Environmental exposures during military deployments to Iraq and Afghanistan may lead to higher rates of respiratory complaints and diagnoses. This study investigates whether there is a relationship between rates of asthma diagnosis and severity associated with military deployment. Methods: Retrospective review of active duty Army personnel underwent fitness for duty evaluation (Medical Evaluation Board) for asthma. The electronic medical record was reviewed for onset of diagnosis (pre- or post-deployment), disease severity, screening spirometry, bronchodilator response and bronchoprovocation testing. We compared patients with and without a history of combat deployment to Operations Iraqi Freedom/Enduring Freedom. Results: Four hundred consecutive Army personnel with a clinical diagnosis of asthma were evaluated. Equal numbers of patients had deployed (48.5%) versus never deployed (51.5%). Of those who deployed, 98 (24.5%) were diagnosed post-deployment. The diagnosis of asthma was objectively confirmed in 74.8% of patients by obstructive screening spirometry, bronchodilator response, and/or methacholine challenge testing. There were no significant differences in spirometry between deployers and non-deployers or based on pre- and postdeployment diagnosis. Similarly, asthma severity classification did not differ between deployed and non-deployed service members, or by pre- and post-deployment diagnosis status. Conclusions: Among active duty military personnel with career limiting asthma, there is no significant relationship between rates of diagnosis or severity based on history of deployment to Southwest Asia.
Asthma, deployment, military personnel, pulmonary function testing
Introduction Combat deployments to Iraq and Afghanistan in Southwest Asia (SWA) have coincided with environmental exposures to inhaled particulate matter (PM) and increased respiratory symptoms among active duty military personnel [1,2]. Prior research has addressed airway symptoms and respiratory illness resulting from oil fire exposure in the first Gulf War [3,4]. However, current active duty service members (ADSM) are mobilized to SWA for longer periods of time and often for multiple deployments, raising concern that increased exposures may result in a rising burden of acute and chronic respiratory disease. Surveillance data by the United States Army Public Health Command demonstrated higher levels of PM secondary to dust, frequent sand storms, burn pits, explosives and vehicle exhaust among others. Additionally, non-specific upper and lower respiratory symptoms such as rhinorrhea, wheezing, cough and dyspnea have increased significantly based on survey data during the past decade of war[5]. Correspondence: Jacob F. Collen, Pulmonary/Critical Care Service (MCHE-MDP), San Antonio Military Medical Center, 3551 Roger Brooke Drive, JBSA Fort Sam Houston, TX 78234, USA. E-mail: [email protected]
History Received 6 September 2014 Revised 23 September 2014 Accepted 1 October 2014 Published online 22 October 2014
In susceptible individuals, prolonged exposure and inhalation of dust particles may result in increased pulmonary symptoms and/or result in diagnoses of respiratory disease, such as reactive airways disease, asthma or other airway disorders. However, there is little direct evidence that pulmonary toxicity explains these symptoms or clearly links them to deployment-related exposures [6]. A cluster of cases of acute eosinophilic pneumonia from Iraq/Afghanistan has been described which may have been linked to new onset or increased tobacco use in theater [7,8]. Another cohort of soldiers with histologic evidence of constrictive bronchiolitis has been published; however, these changes were of unclear clinical significance, given the paucity of abnormal physiologic and imaging findings [9]. These studies do not address the vast majority of cases of ADSM with respiratory symptoms of variable severity. The majority of literature on deployment-related respiratory exposures and resultant respiratory symptoms indicates a possible relationship with asthma and reactive airways symptoms [3,5]. Asthma is a relatively common condition in ADSM, despite the diagnosis limiting entrance into the military, and prior research indicates that a significant portion of new recruits are under diagnosed with asthma [10]. In addition, recent changes in medical guidelines for retention of
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military personnel allow soldiers with well-controlled asthma to remain in military service [11]. This potentially increases the pool of ADSM with compromised respiratory status prior to deployment. One study identified 5% of deploying service members with pre-existing asthma. Survey data from this study indicated a significant rise in respiratory symptoms among both asthmatics and non-asthmatics, and among asthmatics, an increase in healthcare utilization and symptoms among those with poor disease control at baseline [12]. A retrospective review of several thousand Veterans’ Administration (VA) medical records noted higher rates of ‘‘new-onset’’ asthma in deployed military personnel between 2004 and 2007 compared to non-deployed personnel stationed in the United States (6.6 versus 4.3%) [13]. Like much of the literature on this topic, these studies were limited by a paucity or lack of spirometry. Given that asthmatic symptoms are commonly reported post-deployment, the purpose of our study was to review medical records of ADSM diagnosed with asthma and determine if there is a significant relationship between asthma diagnoses and disease severity based on deployment status. Active duty personnel undergoing a Medical Evaluation Board (MEB) have chronic asthmatic symptoms felt to be incompatible with continued military service and may be referred to pulmonary specialists for evaluation.
Methods This study was conducted as a retrospective review of Department of Defense (DoD) electronic medical records after obtaining written approval from our hospital’s Institutional Review Board (IRB # C.2010.126 d). The MEB database was queried to identify ADSM with an International Classification of Disease, 9th edition (ICD-9) code for asthma (493.xx) for five consecutive years from 2005 to 2009. Patient records were abstracted from the database for ADSM who were undergoing an MEB (fitness for duty evaluation) for asthma. These patients referred to the MEB program had symptoms severe enough to limit their ability to continue active duty service in the military. Medical records that lacked any medical encounters or objective clinical information about the diagnosis of asthma were excluded from further analysis. Deployment information for Operations Iraqi Freedom/Enduring Freedom for individuals with qualifying medical records was obtained from the Armed Forces Health Surveillance Center. After the initial query was conducted and qualifying subjects with an asthma diagnosis were identified, consecutive electronic medical records were reviewed to obtain the following information: (1) patient demographics; (2) date of initial diagnosis; (3) asthma diagnosis prior to military service; (4) smoking history; (5) pulmonary function testing (PFT) results to include forced expiratory volume in one second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio (actual and predicted), post-bronchodilator FEV1; (6) methacholine challenge test (MCT) results; and (7) asthma severity. Spirometry was reviewed to determine if patients underwent a standard forced expiratory maneuver from maximal inhalation to maximal exhalation to record the FEV1 and FVC in accordance with American Thoracic Society standards for
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spirometry [14]. Reference values were taken from National Health and Nutrition Examination Survey III (NHANES III) equations [15]. Obstruction was defined as an FEV1/FVC ratio below the 5th percentile predicted (lower limits of normal based on the NHANES III reference equations in accordance with the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines) [15,16]. Patients were given two puffs of a short-acting beta-agonist to measure FEV1 improvement post-bronchodilator. Methacholine challenge testing was typically administered at the following concentrations: normal saline, 0.0625, 0.25, 1.0, 4, 8, and 16 mg/ml. Testing was repeated for all methacholine concentrations until maximal concentration or a 20% drop in the FEV1. The bronchoprovocation test was considered positive with 20% decrease in FEV1 at a dose of 4 mg/ml or less [17]. The diagnosis of asthma was based on: (1) FEV1/FVC ratio below the 5th percentile of the normal distribution (lower limit of normal) with evidence of airway obstruction on spirometry; (2) a bronchodilator response412% or 200 ml for FEV1 representing airflow variability; or (3) MCT with a greater than 20% decline in the FEV1 indicating bronchial hyperresponsiveness [14,15,17]. Patients were classified into three groups based on deployment history to Iraq (Operation Iraqi Freedom) and/ or Afghanistan (Operation Enduring Freedom). The timing of the diagnosis of asthma (pre-or post-deployment) was noted and patients were categorized as: (1) never deployed, (2) diagnosis pre-deployment or (3) diagnosis post-deployment. Further comparison was based on spirometry values (FEV1, FVC and FEV1/FVC) and asthma severity. Outcomes The primary outcomes of our study were whether or not rate of diagnosis and severity of asthma differed based on deployment status. Secondary outcomes assessed whether differences existed between the comparison groups with regards to spirometric values. Statistical analysis Statistical analysis was performed using commercially available software (R Version 3.0.2). Data are expressed as mean ± SD, unless otherwise noted. Normality was tested for the demographic and PFT variables, and a Student’s t test or Mann–Whitney U test was used as appropriate between the two groups. Specific comparisons were made for age, tobacco use, FEV1 (% predicted), FEV1 post-bronchodilator (% predicted) and percent change, FVC (% predicted), FEV1/FVC ratio and severity of disease. p Values less than 0.05 were considered statistically significant.
Results Four hundred consecutive patients with asthma and complete medical records were included in the final analysis after review of 1867 patient files in the Department of the Army’s MEB database between the years 2005 and 2009. The majority of patients were male (n ¼ 291, 73%). Based on Armed Forces deployment data, 194 (48.5%) individuals had deployed to SWA on one or more occasion for greater than
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60 days (Figure 1). The timing of asthma diagnosis was split equally between pre-deployment (n ¼ 93) and postdeployment (n ¼ 101). Non-deployers were younger than deployers (25.4 ± 7.0 years versus 27.1 ± 6.4 years, p ¼ 0.01), but there was no significant age difference between those diagnosed pre- and post-deployment. One quarter of the cohort smoked cigarettes and although there was a slight trend towards more smokers among the group that had deployed, there was no difference between those with a pre- or postdeployment diagnosis (Table 1). Among those who had deployed, the duration of deployment was longer for those with a pre-deployment diagnosis (373 ± 185 days) compared to those with a post-deployment diagnosis (329 ± 185). Pulmonary function test results were available for 355 (84%) of the cohort, equally split between deployed and nondeployed patients, and those with pre- and post-deployment diagnosis (Table 2). Comparison between subgroups demonstrated that the FEV1/FVC ratio was decreased in nondeployers compared to deployers. Although this difference was statistically significant, it did not appear to be clinically significant. Similarly, there was a trend towards a lower FEV1/FVC ratio in those with pre-deployment compared to post-deployment diagnosis, also too small a difference likely to be of clinical significance. There were no other significant differences in spirometry between groups. Testing for bronchodilator responsiveness was performed in 227 (57%)
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patients and 119 (30%) had a positive test (increase of 12% and 200 ml in FEV1) (Table 2). A diagnosis of asthma based on objective testing was identified in 74.8% of the entire cohort. Similar percentages (76.2 and 73.2%) were noted for all patients in the nondeployed and deployed groups, respectively (Figure 2). Fixed obstruction on spirometry was evident in 43.0% of the cohort with similar values for non-deployers and deployers (42.2 versus 44.3%). A similar range of test results (non-deployers versus deployers) was seen for post-BD response (30.1 versus 29.4%, respectively) and MCT (32.5–30.4%). When those asthma patients without any documented studies were excluded, 79.1% of the overall group met diagnostic criteria for asthma. Nearly half (47.9%) had fixed obstruction on spirometry, 46.9% responded to a bronchodilator and 94.7% had a reactive MCT when tested. The majority of patients were diagnosed with mild persistent (39%) or moderate persistent (44%) asthma. Seven percent had severe persistent asthma and 10% had exercise-induced asthma. There was no correlation between disease severity and deployment status (Figure 3). Nondeployers and deployers had similar percentages for mild asthma (34 versus 43%), moderate asthma (45 versus 41%) and severe asthma (8 versus 6%). Among those who had deployed, similar percentages for disease severity were present based on pre- or post-deployment asthma diagnosis.
Figure 1. Deployment history. Distribution of active duty service members with asthma based on deployment history and whether asthma diagnosis was established pre- or post-deployment.
MEB for Asthma (n = 400)
Deployed n = 194 (48.5%)
Asthma Diagnosis PreDeployment n = 93 (23.3%)
Non-Deployed n = 206 (51.5%)
Asthma Diagnosis PostDeployment n = 101 (25.2%)
Table 1. Clinical and demographic variables. Clinical and demographic variables for subjects based on deployment and non-deployment classification.
N Male (%) Age (years) Deployment duration (days) Smoking history
Overall cohort
Non-deployers
Deployers
p Value
Pre-deployment diagnosis
Post-deployment diagnosis
p Value
400 291 (72.8%) 26.2 ± 6.8 N/A 96 (24%)
206 135 (65.5%) 25.4 ± 7.0 N/A 41 (25%)
194 156 (80.4%) 27.1 ± 6.4 350 ± 186 55 (28%)
0.44 0.10 0.01 N/A 0.06
93 70 (73.5%) 26.8 ± 6.7 373 ± 185 25 (27%)
101 86 (85.1%) 27.3 ± 6.2 329 ± 185 30 (30%)
0.48 0.09 0.30 0.05 0.45
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Table 2. Pulmonary function testing.
N (%) FEV1 (% predicted) FVC (% predicted) FEV1/FVC (predicted) FEV1/FVC (actual) Post-BD FEV1 (% predicted)
Overall cohort
Non-deployers
Deployers
p Value
Pre-deployment diagnosis
Post-deployment diagnosis
p Value
337 (84%) 78.6 ± 17.5 87.5 ± 16.9 83.5 ± 6.1 75.1 ± 11.1 85.0 ± 16.7
173 (84%) 77.9 ± 18.0 88.0 ± 17.6 84.2 ± 4.7 74.6 ± 12.0 84.6 ± 18.1
169 (87%) 79.2 ± 17.1 87.1 ± 16.1 82.8 ± 7.2 75.6 ± 10.1 85.3 ± 15.4
– 0.51 0.63 – 0.05 0.76
82 (88%) 77.9 ± 18.7 86.0 ± 17.4 83.7 ± 3.6 75.2 ± 10.0 84.0 ± 15.7
87 (86%) 80.5 ± 15.4 88.1 ± 15.0 82.0 ± 9.5 76.1 ± 10.2 86.6 ± 15.1
– 0.17 0.21 – 0.07 0.18
Comparison of pulmonary function testing values for non-deployer and deployer groups with additional comparison within the deployer group based on whether the diagnosis of asthma was made pre- or post-deployment. FEV1 forced expiratory volume at one second; FVC forced vital capacity; BD bronchodilator
90% ALL
Non-Deploy
Deploy
Pre-Deploy
Post-Deploy
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80%
75% 76%
73%
70%
76% 70%
60% 50%
50% 43% 42% 44%
40%
40% 30% 30% 29%
30%
32% 33%
32%
30% 31% 30%
27%
20% 10% 0% Obstrucon
Post-BD
MCT
Any
Figure 2. Diagnostic criteria for asthma. Percentage of all patients with positive studies. Obstruction–reduction in FEV1/FVC ratio below the lower limits of normal or 5th percentile of the predicted value (based on the NHANES III reference equations in accordance with the 2005 ATS/ERS guidelines); Post-BD – 12% increase in FEV1 post-bronchodilator; MCT – reactive methacholine challenge test.
Discussion Among a cohort of patients with duty limiting asthma, deployment to SWA was not related to the rate of diagnosis or disease severity. The majority (75%) of ADSM in this cohort were diagnosed with asthma without having ever deployed or prior to SWA deployment. A smaller percentage (25%) was diagnosed post-deployment. Among those who deployed, there was no difference in clinical severity of disease or spirometry based on diagnosis pre- or post-deployment. In fact, non-deployers demonstrated a slightly lower (although statistically significant) FEV1/FVC ratio, and there was a trend towards a lower ratio in patients with a pre-deployment diagnosis. It was not determined what other differences may exist between these groups, or if post-deployment asthmatics represent a separate phenotype from those within the military that lack deployment exposures, or asthmatics without military service.
There is ongoing concern surrounding development of respiratory disease in ADSM following deployment to SWA. The most recently published study on this topic by Morris et al. prospectively evaluated ADSM 6 months postdeployment with a comprehensive evaluation that included spirometry, chest imaging, MCT and bronchoscopy. This study demonstrated that the majority of established respiratory diagnoses (40%) comprised airway hyperreactivity (AHR) syndromes, predominantly asthma [18]. The specific etiology of AHR was not established but could be related to exacerbation of pre-existing disease or new disease from PM exposure. Prior studies have demonstrated that asthma may be under diagnosed among new recruits [10] and may be increased in those persons with duties that entail a greater risk of environmental exposure to allergens and activity [19]. The current literature on asthma in relation to deployment has
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60% Non-Deployed
Deployed
Pre-Deploy Dx
Post-Deploy Dx
49%
50%
40%
40%
45%
45%
43%
41%
39%
34%
30%
20% 12% 8%
10%
8% 6%
7%
6%
7% 3%
0%
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Mild
Moderate
Severe
Exercise
Figure 3. Asthma severity. (mild, moderate, severe, exercise-induced) based on the percentage of total and categorized by deployment history (nondeployed, deployed) and whether the diagnosis of asthma was established pre- or post-deployment. There were no significant differences in the distribution of cases between deployed and non-deployed providers (exercise-induced, p ¼ 0.12; mild, p ¼ 0.96; moderate, p ¼ 0.15; severe, p ¼ 0.65). Nor were there any significant differences in the distribution of cases based on whether the diagnosis was established pre- or post-deployment (exerciseinduced, p ¼ 0.69; mild, p ¼ 0.31; moderate, p ¼ 0.44; severe, p ¼ 1.00).
demonstrated an increased rate of diagnosis post-deployment; however, these studies have been based primarily on survey results, or studies with limited spirometric data that relied on a clinical diagnosis. Szema and colleagues evaluated veterans’ medical records from their region in the northeast United States and separated them into groups based on deployment history. They found a higher rate of asthma diagnosis among those who had deployed (6.3 versus 4.4%), with an increase in symptoms leading to clinical encounters requiring spirometry [13,20]. A minority of patients in these studies had spirometry performed, and symptoms and diagnoses were based on a mix of primary care encounters rather than by a documented subspecialty referral to a pulmonologist. Roop et al. evaluated the impact of deployment on asthmatic and non-asthmatic subjects in a post-deployment survey and found that respiratory symptoms (cough, wheezing, sputum production, chest pain/tightness and allergic symptoms) were increased in both groups, but that the majority of symptoms and healthcare utilization in the subgroup with asthma occurred among those with poor baseline control [12]. Their study also found a high rate of smoking, increasing cigarette use during deployment and significantly associated with symptoms in both groups, notably more so in the subgroup with poor baseline asthma control. Recent studies of deployed military personnel have demonstrated that although respiratory complaints increase after deployment, they are not clearly linked to deploymentrelated environmental exposures or do not correlate with increased diagnosis rates or measures of healthcare utilization. An investigation by the Army Public Health Command found a significant rise in respiratory complaints and medical encounters post-deployment, which was not significantly related to the number of deployments or deployment duration [21]. Baird et al. also evaluated the impact of the 2003 Al-Mishraq sulfur plant fire to nearby service members.
Subjective respiratory complaints worsened among those post-deployment, as did clinical encounters to evaluate respiratory complaints, and overall estimation of health quality was worse among a quarter of respondents. There was not a corresponding increase in encounters for chronic respiratory disorders such as asthma or chronic obstructive pulmonary disease among those subjects with documented fume exposure in comparison to a general pool of respondents [22]. The Millennium Cohort Study is a longitudinal survey study conducted by the Naval Research Center evaluating the relationship between respiratory complaints and disease with deployment. Their ongoing study has identified an increase in respiratory complaints in deployed compared to never deployed personnel (14 versus10%), with no difference in the diagnosis of asthma (1%) or chronic bronchitis (1%). Additionally, significant relationships to diagnosed lung disease are lacking based on proximity to known burn-pit exposures in Iraq and inconsistently related to exposure duration/deployment time [5,6]. Limitations As a retrospective review, this study is subject to selection bias although we purposely selected asthma patients whose disease limited their ability to continue active duty service. As such, one would expect a more chronic course and detailed evaluation with documentation of spirometric abnormalities. Despite the use of this selected population, we identified 30% of the cohort without objective documentation of AHR, which suggests only a clinical diagnosis for asthma. We cannot be sure these patients did not have other evidence of asthma not available for review. Inpatient medical records were not reviewed nor were other types of physiologic testing such as cardiopulmonary exercise testing, plethysmography or impulse oscillometry. Conversely, these patients may have been misdiagnosed and had other pulmonary disorders
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(COPD, vocal cord dysfunction) depending on the extent of the evaluation. We cannot also exclude the possibility that parenchymal lung disease may have impacted the patient’s evaluation. Chest imaging with plain film radiographs and/or chest CT is routine for patients undergoing a medical evaluation board for pulmonary disease and is unlikely to have changed our results. Finally, the active duty population studied is unique and our findings may not apply to a National Guard, Reserve or VA population. Dyspnea among young and otherwise healthy members of the military can be challenging due to several potential confounders including comorbid illness (sleep disorders, psychiatric disease), tobacco use, symptoms that are disproportionate to objective test results, obesity, deconditioning and malingering [18,23]. Although our study did not find a clear association with cigarette use, previous research has cited higher rates of smoking, especially during deployment. Comorbid psychiatric disease and poor quality sleep can lead to fatigue and daytime sleepiness which can impact performance (such as 2-mile physical fitness run times) and perception of symptoms. Finally, obstructive lung disease such as COPD can evolve over time, and our results may be limited by lack of long-term data. Research addressing respiratory complaints in the deployed military population is ongoing. In addition to the confounders listed above, most deployment research is limited by a lack of both pre- and post-deployment spirometry. Recommendations have been made to perform screening in all deployers [24–26]. Unfortunately, performing screening spirometry for all deployers, and follow-up subspecialty referral and testing based on these results is likely cost-prohibitive and limited by subspecialty availability. An unpublished costanalysis by the military calculated that widespread screening spirometry alone for all DoD personnel would be in the tens of millions of dollars, which does not account for additional testing and referrals that would be generated by abnormal initial screening results [27]. An ongoing study conducted at Fort Hood has enrolled 1500 deploying Army personnel and performed pre-deployment spirometry [28]. Preliminary results have demonstrated pulmonary issues such as smoking (18%), persistent dyspnea (3.5%), inhaled medication use (3.1%), failed PT testing (23.4%) and increased body mass index above 30 mg/m2 in 1.9% of the deploying soldiers. Baseline spirometry showed an obstructive ventilatory defect in 8.7% of participants prior to deployment.
Conclusion Deployment-related environmental exposures have an unclear relationship to chronic respiratory disease. Whether such exposures lead to clinical disease, and what the culprit exposures are remains undetermined. In our population of patients with a diagnosis of asthma prompting a fitness for duty evaluation, we did not establish a relationship to SWA deployment. This may indicate that deployment-related lung conditions are subtle and may require a careful evaluation over time to determine the long-term impact on the development of respiratory disease. Furthermore, patients with suspected asthma should undergo adequate testing to meet the established objective criteria for disease. The increase in
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reported respiratory complaints following SWA deployment mandates that the ADSM receive comprehensive medical care, to include pulmonary specialty evaluations when appropriate. As a single evaluation may not reveal evidence of airway hyperreactivity, these patients should be followed longitudinally.
Acknowledgements Dr. Michael Morris is the guarantor for the accuracy and integrity of the data and results presented in this manuscript. Dr. Michael Morris participated in study design, data interpretation, and manuscript writing and editing. Dr. Sally DelVecchio participated in study design, performed all data collection, data interpretation, and the majority of manuscript writing and editing. Dr. Jacob Collen participated in data interpretation, manuscript writing and editing. Dr. Lisa Zacher participated in study design and data interpretation. Dr. Roy Haas, PhD, assisted in performing statistical analysis.
Declaration of interest The opinions in this essay do not constitute endorsement by San Antonio Army Medical Center, the U.S. Army Medical Department, the U.S. Army Office of the Surgeon General, the Department of the Army, Department of Defense, or the U.S. Government of the information contained therein. Dr. Morris is a paid speaker for SpirivaÕ by BoehringerIngelheim. The other authors have no financial interests to disclose. None of the authors have any relevant conflicts of interest to disclose. This study was not supported by any funding or financial sponsorship. The authors alone are responsible for the content and writing of the paper.
References 1. Abraham JH, Baird CP. A case-crossover study of ambient particulate matter and cardiovascular and respiratory medical encounters among US military personnel deployed to southwest Asia. J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 733–739. 2. Weese CB, Abraham JH. Potential health implications associated with particulate matter exposure in deployed settings in southwest Asia. Inhal Toxicol 2009;21:291–296. 3. Lange JL, Schwartz DA, Doebbeling BN, et al. Exposures to the Kuwait oil fires and their association with asthma and bronchitis among gulf war veterans. Environ Health Perspect 2002;110: 1141–1146. 4. Smith TC, Heller JM, Hooper TI, et al. Are Gulf War veterans experiencing illness due to exposure to smoke from Kuwaiti oil well fires? Examination of Department of Defense hospitalization data. Am J Epidemiol 2002;155:908–917. 5. Smith B, Wong CA, Smith TC, et al. Newly reported respiratory symptoms and conditions among military personnel deployed to Iraq and Afghanistan: a prospective population–based study. Am J Epidemiol 2009;170:1433–1442. 6. Smith B, Wong CA, Boyko EJ, et al. The effects of exposure to documented open-air burn pits on respiratory health among deployers of the Millennium Cohort Study. J Occup Environ Med/Am Coll Occup Environ Med 2012;54:708–716. 7. Sine C, Allan P, Haynes R, Scoville S, Shuping E, Hultman A, et al. Case series of 44 patients with idiopathic acute eosinophilic pneumonia in the deployed military setting. Chest 2011;140: 675A–675A(Meeting Abstract). 8. Shorr AF, Scoville SL, Cersovsky SB, et al. Acute eosinophilic pneumonia among US Military personnel deployed in or near Iraq. JAMA 2004;292:2997–3005.
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Downloaded by [New York University] at 00:17 15 November 2015
DOI: 10.3109/02770903.2014.973502
9. King MS, Eisenberg R, Newman JH, et al. Constrictive bronchiolitis in soldiers returning from Iraq and Afghanistan. New Engl J Med 2011;365:222–230. 10. Nish WA, Schwietz LA. Underdiagnosis of asthma in young adults presenting for USAF basic training. Ann Allergy 1992;69:239–242. 11. Army Regulation 40–501. Standards of medical fitness. Washington, DC: Department of the Army; 2002: p. 27. 12. Roop SA, Niven AS, Calvin BE, et al. The prevalence and impact of respiratory symptoms in asthmatics and nonasthmatics during deployment. Military Med 2007;172:1264–1269. 13. Szema AM, Peters MC, Weissinger KM, et al. New-onset asthma among soldiers serving in Iraq and Afghanistan. Allergy Asthma Proc 2010;31:67–71. 14. Miller MR, Hankinson J, Brusasco V, et al. Standardisation of spirometry. Eur Respir J 2005;26:319–338. 15. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med 1999;159:179–187. 16. Pellegrino R, Viegi G, Brusasco V, et al. Interpretative strategies for lung function tests. Eur Respir J 2005;26:948–968. 17. Crapo RO, Casaburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing-1999. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, July 1999. Am J Respir Crit Care Med 2000;161:309–329. 18. Morris MJ, Dodson DW, Lucero PF, et al. Study of active duty military for pulmonary disease related to environmental deployment exposures (STAMPEDE). Am J Respir Crit Care Med 2014. doi: 10.1164/rccm.201402–0372OC[published Online First: Epub Date]j. 19. Katz I, Moshe S, Sosna J, et al. The occurrence, recrudescence, and worsening of asthma in a population of young adults: impact of varying types of occupation. Chest 1999;116:614–618. 20. Szema AM, Salihi W, Savary K, et al. Respiratory symptoms necessitating spirometry among soldiers with Iraq/Afghanistan war
21.
22.
23.
24.
25. 26.
27.
28.
369
lung injury. J Occup Environ Med/Am Coll Occup Environ Med 2011;53:961–965. Abraham JH, DeBakey SF, Reid L, et al. Does deployment to Iraq and Afghanistan affect respiratory health of US military personnel? J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 740–745. Baird CP, DeBakey S, Reid L, et al. Respiratory health status of US Army personnel potentially exposed to smoke from 2003 Al-Mishraq Sulfur Plant fire. J Occup Environ Med/Am Coll Occup Environ Med 2012;54:717–723. Morris MJ, Grbach VX, Deal LE, et al. Evaluation of exertional dyspnea in the active duty patient: the diagnostic approach and the utility of clinical testing. Military Med 2002; 167:281–288. Rose C, Abraham J, Harkins D, et al. Overview and recommendations for medical screening and diagnostic evaluation for postdeployment lung disease in returning US warfighters. J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 746–751. Rose CS. Military service and lung disease. Clin Chest Med 2012; 33:705–714. Zacher LL, Browning R, Bisnett T, et al. Clarifications from representatives of the Department of Defense regarding the article ‘‘Recommendations for medical screening and diagnostic evaluation for postdeployment lung disease in returning US warfighters’’. J Occup Environ Med/Am Coll Occup Environ Med 2012;54: 760–761. Morris MJ, Eschenbacher WL, McCannon CE. Workshop D: recommendation for surveillance spirometry in military personnel. Deployment-related airborne hazards. Washington, DC: Borden Institute; 2013 (in-press). Skabelund A, Morris M. Baseline symptoms and pulmonary function of military personnel prior to deployment. Chest 2013; 144:480A–480A.
