Functioning Level as a Buffer: Longitudinal Associations Between Heart Rate Variability and Post-Traumatic Stress Disorder Risk Over 2 Years

Objective This study examined the modifying effects of functional levels on the associations of the low frequency (LF) and high frequency (HF) components of heart rate variability (HRV) with post-traumatic stress disorder (PTSD) development. Methods Participants with physical injuries were recruited from a trauma center and followed for 2 years. Baseline assessments included LF, HF, and functional levels measured by the Social and Occupational Functioning Scale. Socio-demographic and clinical covariates were collected. PTSD diagnoses were made at 3, 6, 12, and 24 months post-injury using the Clinician-Administered PTSD Scale for DSM-5. Logistic regression analyses were performed to assess associations. Among 538 participants, 58 (10.8%) developed PTSD during the study period. Results A significant modifying effect was found: lower LF/HF were significantly associated with PTSD in patients with lower functioning levels, but not in those with higher functioning levels, with significant interaction terms. Conclusion The study observed functioning level-dependent associations between LF/HF and PTSD development, highlighting the buffering effects of higher functioning levels. These findings underscore the importance of considering functional status in PTSD risk assessments and the potential benefits of interventions aimed at enhancing social and occupational functioning to mitigate PTSD risk.