UCLA

Background. Every year, approximately 2.5 million individuals sustain traumatic physical injuries that require admission to an acute care facility. Several studies suggest that physical injury increases the risk for the development of Post-Traumatic Stress Disorder (PTSD). Nationally, 20% to 40% of acutely injured patients had symptoms consistent with PTSD. Most studies describe the prevalence of PTSD and other mental health conditions post-injury. However, there is limited attention to the effect of pre-existing mental health condition as pre-injury factor, and conclusions from these studies were limited by their small sample sizes, lack of population comparison group, and non-population based. The overall objective of this study was to examine the association between physical injury and PTSD and other mental health conditions in adult patients >18 years who were admitted in ED between 2009-2011. More specifically, those patients who were admitted with physical injury were compared with patients

who had a concurrent diagnosis of PTSD, or concurrent diagnosis of other mental health conditions with patients who did not have these concurrent conditions. The interaction between presenting diagnoses, patient characteristics, hospital setting, location, and risk for outcomes such as mortality rates, and costs were also explored.

Method. This is a cross-sectional, descriptive study that compares the prevalence of Injury (ICD-9-CM 800-999) for patients with and without PTSD (ICD-9-CM 308.91) and patients with and without other mental health diagnoses other than PTSD (ICD-9-CM 290-320) using the National Emergency Department Sample (NEDS) databases who were admitted to a US Emergency Department (ED) between January 1, 2009, through December 31, 2011. The interaction between presenting diagnoses, patient characteristics, hospital setting, location and risk for outcomes such as mortality rates, and costs were explored using univariate, bivariate, and

multivariate analyses.

Results. Adjusted analyses suggested that for the period 2009 to 2011, there were 308, 078,546 ED visits among adults in the US Approximately 22% (N=66,936, 140) of these ED visits had injury-related diagnoses, 0.25% (N=758,528) had PTSD diagnoses, and 25% (N=77,536,048) had mental health diagnoses other than PTSD. There were 133,243 adult patients that were diagnosed with both PTSD and Injury for this period. Adult patients with a diagnosis of PTSD had 1.03-fold higher odds of having injury diagnosis compared to those who are otherwise similar but unaffected adults. Adult patients with mental health diagnoses had

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1.30-fold higher odds of having injury-related ED visits compared to those that are unaffected.

Results from a survey-adjusted multivariate logistic regression analysis indicated that PTSD diagnosis increased the odds of injury-related ED visits to 1.30-fold compared to those that are unaffected. In comparison to adults aged 45-64, those who were aged 18-44 had 1.10-

fold higher odds of an injury, while aged 65-84 had 1.10-fold lesser odds. Males, compared to females, had 1.40-fold higher odds of having injury-related ED visits. Compared to patients with Medicare insurance, those that have private and other insurances had 1.50 and 2.60c-fold higher odds to have injury-related ED visits.

There were significant differences in mortality rates across the studied groups. Injured adult patients compared to otherwise similar but uninjured counterparts had significantly lower mortality rates (0.79% vs. 0.37%, p<0.0001). PTSD diagnosed adults had lower mortality rates in comparison to those that were unaffected (0.20% vs. 0.56%, p<0.0001). PTSD diagnosed patients with injury diagnoses also had a slightly lower mortality rate compared to their uninjured counterparts (0.19% vs. 0.20%, p<0.001). The mortality rates among adults with other mental health diagnoses compared to those that were unaffected were also lower (0.53% vs. 0.70%, p<0.0001). Adult patients with concurrent diagnoses of other mental health and injury showed a lesser mortality rate compared to those without injuries (0.25% vs. 0.61%, p<0.0001). There were significant differences in cost across the groups. Adult patients with injury had higher mean costs compared to those without injury ($45,271 vs. $33,197, p <0.001). Uninjured PTSD diagnosed adults showed lower costs compared to those that did not have PTSD ($21,061 vs. $33,272, p<0.001). Similarly, adults with mental health conditions without injury had lower costs compared to those who did not ($30,269 vs. $35,196, p<0.001). There was incremental

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increase in costs for ED patients with concurrent diagnoses. The mean cost for patients with a diagnosis of PTSD was $21,061. The cost increased by 26% when there was concurrent diagnoses of PTSD and Injury ($28, 319). The costs increased by 54% when there was concurrent diagnoses of PTSD, Injury, and other mental health conditions ($45,431).

Conclusion. These findings indicate that when investigating injury as an outcome, the

presence of PTSD and other mental health conditions is a potential confounder and effect modifier. For example, this study showed that PTSD diagnosis didn't increase the odds of dying among those who were diagnosed with injury. Likewise, diagnoses of injury didn't increase the odds of dying among those diagnosed with PTSD. In regards to hospital costs, adult patients with injury or PTSD diagnoses incurred more hospital costs compared to similar but unaffected patients. Results also showed that there were incremental costs incurred with the increased number of diagnoses. For example, combined diagnoses of Injury and PTSD increased the cost by 23% compared to just having PTSD diagnosis alone. Having concurrent diagnoses of PTSD, Injury, and other mental health disorder increased the cost further by 54% compared to just having a diagnosis of PTSD. Based from these findings, it is suggested that mental health and PTSD screening needs to be evaluated upon entry to ED, and immediate referral to mental health services must be considered a priority for patients with an injury. Strategies for injury prevention need to include mental health evaluation and management at the primary, secondary, and tertiary care service settings.