Heart Rate Variability and Posttraumatic Stress Disorder.

Letters COMMENT & RESPONSE Heart Rate Variability and Posttraumatic Stress Disorder To the Editor We appreciate the thoughtful editorial by Shah and Vaccarino 1 in JAMA Psychiatry in response to our prospective investigation of the association of predeployment heart rate variability (HRV) with postdeployment posttraumatic stress disorder (PTSD) in military service personnel. 2 We agree that the findings are in need of replication by other groups, par- ticularly with attention to limitations inherent in HRV indi- ces including the low frequency to high frequency ratio, among others. 3 Shah and Vaccarino 1 mentioned several concerns, briefly addressed here. The authors highlighted the attrition rate from predeploy- ment to postdeployment (39% in the first phase of the Marine Resiliency Study [MRS-I] and 36% in the second phase of the Marine Resiliency Study [MRS-II]) as a factor limiting causal inference. The t test comparisons between participants with and without a postdeployment visit yielded no differences in predeployment HRV, PTSD symptom scores, or Life Events Checklist scores. However, it remains possible that service members who did not return for their postdeployment assess- ment (eg, left the military following deployment) may have been a group uniquely affected by deployment. The main causes of attrition were deployment-related death, injury of such severity that postdeployment return with the battalion was precluded, or high mobility (eg, change of battalion, as- signment to specialized training, discharge from the military, and interference from a civilian work schedule). Of the avail- able participants for follow-up, only a very small number ac- tively declined to participate in the postdeployment assess- ment (4% in MRS-I and 0.04% in MRS-II). The MRS attrition rates matched other recent longitudinal studies of PTSD in ser- vice members (40% in the study by Stein et al 4 and 50% in the study by Polusny et al 5 ), with causes of attrition (ie, high mo- bility) being similar across studies. The authors also commented on the lack of inclusion of factors such as medical history, health behaviors, depres- sion, and trauma history. Our access to medical health rec- ords was incomplete; however, it should be noted that owing to deployment requirements, this was a relatively healthy population. When predeployment Beck Depression Inven- tory 2 scores were included in the regression model, the nor- malized low frequency to high frequency ratio retained sta- tistical significance as a predictor of postdeployment PTSD (odds ratio, 1.61; 95% CI, 1.11-2.34; P = .01). Similar results were obtained with postdeployment Beck Depression Inventory 2 jamapsychiatry.com scores. Likewise, when Life Events Checklist scores were in- cluded in the regression, again the low frequency to high fre- quency ratio retained its significance (odds ratio, 1.61; 95% CI, 1.12-2.30; P = .01). Therefore, we argue that predeployment HRV, although very likely to be influenced by a host of vul- nerability factors, may nevertheless hold independent value in understanding PTSD risk and resilience. We look forward to replication and extension of these findings, which may ul- timately provide new targets for prevention and treatment. Arpi Minassian, PhD Dewleen G. Baker, MD Victoria B. Risbrough, PhD Author Affiliations: Center of Excellence for Stress and Mental Health, Veterans Administration, San Diego, California (Minassian, Baker, Risbrough); Department of Psychiatry, University of California–San Diego (Minassian, Baker, Risbrough); Veterans Administration San Diego Healthcare System, San Diego, California (Baker, Risbrough). Corresponding Author: Arpi Minassian, PhD, Department of Psychiatry, University of California–San Diego, 200 W Arbor Dr, Mailcode 8620, San Diego, CA 92103-8620 (aminassian@ucsd.edu). Published Online: December 23, 2015. doi:10.1001/jamapsychiatry.2015.2663. Conflict of Interest Disclosures: None reported. Funding/Support: This study was funded by VA Health Service Research and Development project No. SDR 09-0128 (Drs Baker and Risbrough), the US Marine Corps (Drs Baker and Risbrough), the Navy Bureau of Medicine and Surgery (Drs Minassian, Baker, and Risbrough), the Center of Excellence for Stress and Mental Health (Drs Minassian, Baker, and Risbrough), and the National Institutes of Health (MH093500) (Drs Baker and Risbrough). Role of the Funder/Sponsor: The funding organizations had a role in the design and conduct of the study but not the collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Editorial Note: This letter was shown to the corresponding author of the original article, who declined to reply on behalf of the authors. 1. Shah A, Vaccarino V. Heart rate variability in the prediction of risk for posttraumatic stress disorder. JAMA Psychiatry. 2015;72(10):964-965. 2. Minassian A, Maihofer AX, Baker DG, Nievergelt CM, Geyer MA, Risbrough VB; Marine Resiliency Study Team. Association of predeployment heart rate variability with risk of postdeployment posttraumatic stress disorder in active-duty Marines. JAMA Psychiatry. 2015;72(10):979-986. 3. Berntson GG, Bigger JT Jr, Eckberg DL, et al. Heart rate variability: origins, methods, and interpretive caveats. Psychophysiology. 1997;34(6):623-648. 4. Stein MB, Kessler RC, Heeringa SG, et al; Army STARRS Collaborators. Prospective longitudinal evaluation of the effect of deployment-acquired traumatic brain injury on posttraumatic stress and related disorders: results from the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS) [published online September 4, 2015]. Am J Psychiatry. doi:10.1176 /appi.ajp.2015.14121572. 5. Polusny MA, Kehle SM, Nelson NW, Erbes CR, Arbisi PA, Thuras P. Longitudinal effects of mild traumatic brain injury and posttraumatic stress disorder comorbidity on postdeployment outcomes in national guard soldiers deployed to Iraq. Arch Gen Psychiatry. 2011;68(1):79-89. (Reprinted) JAMA Psychiatry Published online December 23, 2015 Copyright 2015 American Medical Association. All rights reserved. Downloaded From: http://archpsyc.jamanetwork.com/ by a University of California - San Diego User on 01/04/2016 E1