G Model
JINJ-5562; No. of Pages 1 Injury, Int. J. Care Injured xxx (2013) xxx–xxx
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Letter to the Editor Battle and non-battle injury and posttraumatic stress disorder in military personnel I read with interest the recent article by Macgregor et al. [1]. The authors conducted risk assessment of posttraumatic stress disorder (PTSD) in patients of military personnel with battle injury (BI). They also conducted sub-analysis on predictive factors of PTSD in patients with BI. As a result, odds ratio (OR) and 95% confidence interval (CI) of patients with BI against patients with non BI for PTSD were 2.10 and 1.60–2.75, respectively. Furthermore, ORs (95% CIs) of BI patients with moderate injury, with serious-severe injury, with previous mental health diagnosis within 1 year of deployment, and with prior BI for PTSD were 1.49 (1.12–2.00), 1.64 (1.01–2.68), 2.69 (1.50–4.81), and 1.96 (1.22–3.16), respectively. I have two concerns on their study. First, the authors used many independent variables for the adjustment of OR. The number of independent variables to determine predictors of PTSD in patients with BI was 15. Among them, 5 independent variables were composed of 3 items of reply. This means that 20 independent variables were used for logistic regression analysis. The number of events per independent variable in multivariate regression analysis should be 10–20 to keep statistical power [2], and the authors should prepare 200–400 events for stable estimates. As the number of PTSD in patients with BI was 447, their study satisfied the criteria. More events would make stable estimate for predicting PTSD. Second, caution should be paid for their procedure of PTSD judgement. The authors used questionnaire for the screening of PTSD with 4-item instrument, named PC-PTSD [3]. A validation study was also quoted as a reference [4]. As they used 3/4 as a cutoff point of positive screen for PTSD, and I recommend quoting other references [5,6], because Veteran Administration changed the cut-off point of PC-PTSD from 2/3 to 3/4 in 2005. In addition, PC-PTSD is not an instrument for clinical diagnosis of PTSD, which was conducted by Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) PTSD symptoms [7]. Compared with PC-PTSD, PTSD checklist (PCL) was constructed as self-report measures of PTSD with keeping validity [8], and there is a risk of overestimation of PTSD prevalence by questionnaire survey.
Anyway, their study has presented information to prevent PTSD for military personnel. As a further study, validation study on PC-PTSD should be conducted by using a part of their study population. References [1] Macgregor AJ, Tang JJ, Dougherty AL, Galarneau MR. Deployment-related injury and posttraumatic stress disorder in US military personnel. Injury 2013;44:1458–64. [2] Concato J, Feinstein AR. Monte Carlo methods in clinical research: applications in multivariable analysis. Journal of Investigative Medicine 1997;45:394–400. [3] Prins A, Ouimette P, Kimerling R, Cameron RP, Hugelshofer DS, Shaw-Hegwer J, et al. The Primary Care PTSD screen (PC-PTSD): development and operating characteristics. Primary Care Psychiatry 2003;9:9–14. [4] Bliese PD, Wright KM, Adler AB, Cabrera O, Castro CA, Hoge CW. Validating the primary care posttraumatic stress disorder screen and the posttraumatic stress disorder checklist with soldiers returning from combat. Journal of Consulting and Clinical Psychology 2008;76:272–81. [5] Seal KH, Bertenthal D, Maguen S, Gima K, Chu A, Marmar CR. Getting beyond don’t ask; don’t tell: an evaluation of US Veterans Administration postdeployment mental health screening of veterans returning from Iraq and Afghanistan. American Journal of Public Health 2008;98:714–20. [6] Davis SM, Whitworth JD, Rickett K. Clinical inquiries. What are the most practical primary care screens for post-traumatic stress disorder? The Journal of Family Practice 2009;58:100–1. [7] DSM-IV A. Diagnostic and Statistic Manual of Mental Disorders. Washington, DC: American Psychiatric Association; 1994. [8] Wilkins KC, Lang AJ, Norman SB. Synthesis of the psychometric properties of the PTSD checklist (PCL) military, civilian, and specific versions. Depression and Anxiety 2011;28:596–606.
Tomoyuki Kawada* Department of Hygiene and Public Health, Nippon Medical School, Japan *Correspondence to: Department of Hygiene and Public Health, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8602, Japan. Tel.: +81 3 3822 2131; fax: +81 3 5685 3065 E-mail address: [email protected] (T. Kawada)
0020–1383/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2013.10.047
Please cite this article in press as: Kawada T. Battle and non-battle injury and posttraumatic stress disorder in military personnel. Injury (2013), http://dx.doi.org/10.1016/j.injury.2013.10.047
JINJ-5562; No. of Pages 1 Injury, Int. J. Care Injured xxx (2013) xxx–xxx
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Letter to the Editor Battle and non-battle injury and posttraumatic stress disorder in military personnel I read with interest the recent article by Macgregor et al. [1]. The authors conducted risk assessment of posttraumatic stress disorder (PTSD) in patients of military personnel with battle injury (BI). They also conducted sub-analysis on predictive factors of PTSD in patients with BI. As a result, odds ratio (OR) and 95% confidence interval (CI) of patients with BI against patients with non BI for PTSD were 2.10 and 1.60–2.75, respectively. Furthermore, ORs (95% CIs) of BI patients with moderate injury, with serious-severe injury, with previous mental health diagnosis within 1 year of deployment, and with prior BI for PTSD were 1.49 (1.12–2.00), 1.64 (1.01–2.68), 2.69 (1.50–4.81), and 1.96 (1.22–3.16), respectively. I have two concerns on their study. First, the authors used many independent variables for the adjustment of OR. The number of independent variables to determine predictors of PTSD in patients with BI was 15. Among them, 5 independent variables were composed of 3 items of reply. This means that 20 independent variables were used for logistic regression analysis. The number of events per independent variable in multivariate regression analysis should be 10–20 to keep statistical power [2], and the authors should prepare 200–400 events for stable estimates. As the number of PTSD in patients with BI was 447, their study satisfied the criteria. More events would make stable estimate for predicting PTSD. Second, caution should be paid for their procedure of PTSD judgement. The authors used questionnaire for the screening of PTSD with 4-item instrument, named PC-PTSD [3]. A validation study was also quoted as a reference [4]. As they used 3/4 as a cutoff point of positive screen for PTSD, and I recommend quoting other references [5,6], because Veteran Administration changed the cut-off point of PC-PTSD from 2/3 to 3/4 in 2005. In addition, PC-PTSD is not an instrument for clinical diagnosis of PTSD, which was conducted by Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) PTSD symptoms [7]. Compared with PC-PTSD, PTSD checklist (PCL) was constructed as self-report measures of PTSD with keeping validity [8], and there is a risk of overestimation of PTSD prevalence by questionnaire survey.
Anyway, their study has presented information to prevent PTSD for military personnel. As a further study, validation study on PC-PTSD should be conducted by using a part of their study population. References [1] Macgregor AJ, Tang JJ, Dougherty AL, Galarneau MR. Deployment-related injury and posttraumatic stress disorder in US military personnel. Injury 2013;44:1458–64. [2] Concato J, Feinstein AR. Monte Carlo methods in clinical research: applications in multivariable analysis. Journal of Investigative Medicine 1997;45:394–400. [3] Prins A, Ouimette P, Kimerling R, Cameron RP, Hugelshofer DS, Shaw-Hegwer J, et al. The Primary Care PTSD screen (PC-PTSD): development and operating characteristics. Primary Care Psychiatry 2003;9:9–14. [4] Bliese PD, Wright KM, Adler AB, Cabrera O, Castro CA, Hoge CW. Validating the primary care posttraumatic stress disorder screen and the posttraumatic stress disorder checklist with soldiers returning from combat. Journal of Consulting and Clinical Psychology 2008;76:272–81. [5] Seal KH, Bertenthal D, Maguen S, Gima K, Chu A, Marmar CR. Getting beyond don’t ask; don’t tell: an evaluation of US Veterans Administration postdeployment mental health screening of veterans returning from Iraq and Afghanistan. American Journal of Public Health 2008;98:714–20. [6] Davis SM, Whitworth JD, Rickett K. Clinical inquiries. What are the most practical primary care screens for post-traumatic stress disorder? The Journal of Family Practice 2009;58:100–1. [7] DSM-IV A. Diagnostic and Statistic Manual of Mental Disorders. Washington, DC: American Psychiatric Association; 1994. [8] Wilkins KC, Lang AJ, Norman SB. Synthesis of the psychometric properties of the PTSD checklist (PCL) military, civilian, and specific versions. Depression and Anxiety 2011;28:596–606.
Tomoyuki Kawada* Department of Hygiene and Public Health, Nippon Medical School, Japan *Correspondence to: Department of Hygiene and Public Health, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8602, Japan. Tel.: +81 3 3822 2131; fax: +81 3 5685 3065 E-mail address: [email protected] (T. Kawada)
0020–1383/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2013.10.047
Please cite this article in press as: Kawada T. Battle and non-battle injury and posttraumatic stress disorder in military personnel. Injury (2013), http://dx.doi.org/10.1016/j.injury.2013.10.047
