Patterns of Illness Explaining the Associations between Posttraumatic Stress Disorder and the Use of CT

Abstract

To examine the relationship between posttraumatic stress disorder (PTSD) and computed tomography (CT) utilization and to determine whether there were patterns of comorbid illness that could explain the relationship. The study was approved by the University of Iowa Institutional Review Board and the Iowa City Veterans Affairs Medical Center Research and Development Committee. By using a retrospective cohort design, a national sample of new veteran enrollees aged 18-35 years was studied. Associations were examined between the presence of PTSD, receipt of at least one and multiple CT scans, comorbid medical conditions (eg, abdominal pain, headaches), and measures of health care utilization (eg, primary care, emergency room, and mental health visits) and the daily probability of the receipt of at least one CT scan before and after a diagnosis of PTSD. Analyses included sequential multivariable generalized linear mixed models to examine the independent relationship between PTSD and CT scan utilization. Among the full cohort, 13.0% (10 018 of 76 812) received at least one CT scan. PTSD was identified in 21.1% (16 182 of 76 812) of the cohort, and 22.9% (3711 of 16 182) of veterans with PTSD received at least one CT scan as compared with 10.4% (6307 of 60 630) of veterans without PTSD (P < .0001). In sequential modeling, comorbid factors explaining the relationship between CT scans and PTSD were traumatic brain injury (odds ratio, 3.54; P < .0001), abdominal pain (odds ratio, 4.01; P < .0001), and headaches (odds ratio, 3.07; P < .0001). Associations were also strong for high levels of emergency room (odds ratio, 2.73; P < .0001) and primary care (odds ratio, 2.38; P < .0001) utilization. The daily chance of receiving a CT scan was seven times higher prior to the recognition of PTSD (daily chance, 0.007 before vs 0.001 after; P < .0001). Young veterans with PTSD are receiving more CT scans compared with those without PTSD; the daily probability of receiving CT scans is higher prior to recognition of PTSD. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13121593/-/DC1.