(272) Risk factors for post-injury mental health conditions: A retrospective cohort study using the Cox proportional hazards model.

Background: : Physical injuries can trigger mental health (MH) conditions, yet the role of demographic and clinical factors in this progression is not well defined. Prior research is often limited in scope, and the impact of medication duration as a risk indicator remains unclear.

Objective: : To evaluate the impact of demographic and clinical factors on the risk of developing a MH condition following a physical injury.

Methods: : A retrospective cohort study of 326,636 individuals with physical injuries in 2024 examined time to first mental health (MH) diagnosis within one-year post-injury. The primary outcome was the time from injury to the first MH diagnosis. Individuals without a diagnosis during follow-up were right censored at the end of the observation period or upon loss to follow-up. A Cox Proportional Hazards model was used to assess the impact of age, gender, injury type, and medication supply duration on MH outcomes. Multicollinearity among predictors was minimal, and no significant interaction terms were detected. Model performance was evaluated using the concordance index (C-index).

Results: : Among the eligible members, 17,476 individuals (5.4%) developed a MH condition post-injury. Most were aged 35 or older (94.3%) and male (58%). The median follow-up time was 312 days (IQR: 198–365 days). The median time from injury to MH diagnosis was 70 days. Compared to the reference group, hazard ratios (HRs) were significantly higher for individuals aged 35–44 (HR: 1.27; p < 0.001), 45–55 (HR: 1.44; p < 0.001), and over 55 (HR: 1.69; p < 0.001), while those under 25 had a lower risk (HR: 0.54; p < 0.001). Both female and males exhibited elevated risks, with HRs of 1.42 (p < 0.001) and 1.45 (p < 0.001), respectively. Injuries involving multiple head regions were significantly associated with an elevated risk (HR: 2.21; p < 0.001), whereas injuries affecting multiple body parts were linked to a modest increase in risk (HR: 1.02; p = 0.018). Conversely, vertebral injuries did not show a statistically significant association (HR: 1.00; p = 0.856). A medication supply duration of 61-90 days significantly increased the risk (HR: 2.26; p < 0.001), whereas a supply of 30 days or less was protective (HR: 0.57; p < 0.001).

Conclusions: : Age, gender, injury location, and medication duration significantly influence post-injury MH risk. Individuals with middle age and above, both males and females, and those with injuries involving multiple head regions or extended medication use are at elevated risk. These findings highlight the need for targeted screening and tailored interventions for high-risk groups.

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