High level of post-traumatic stress symptoms in patients with chronic neck pain is associated with poor mental health but does not moderate the outcome of a multimodal physiotherapy programme

Introduction: Chronic traumatic neck pain has a high prevalence of post-traumatic stress symptoms (PTSS). However, whether PTSS moderates treatment effects is unknown. This study investigated: 1) whether PTSS was associated with patient-reported outcomes and clinical test results at baseline; 2) whether PTSS moderated the effect of a multimodal physiotherapy intervention of exercise therapy and patient education; and 3) whether adherence to the intervention differed across PTSS groups. Methods: Secondary data analysis from a randomized controlled trial on chronic neck pain with 12-month follow-up was conducted. Patients were divided into three groups (NT = non-traumatic, LT = traumatic low PTSS, HT = traumatic high PTSS) based on self-reported onset of pain and the Impact of Event Scale. The baseline data were used to analyze the association of PTSS with patient demographics and scores of physical and mental health-related quality of life, depression, neck-related disability, kinesiophobia, and clinical tests. Baseline, 4-month and 12-month follow-up data were analyzed to investigate possible moderating effects on outcomes. Data on adherence were collected at four months. Results: 115 participants were included (NT n = 45; LT n = 46; HT n = 24). The HT group reported lower mental health scores and more depressive symptoms at baseline. PTSS did not significantly moderate the treatment effect on any outcomes. The HT group tended to have lower adherence to the multimodal physiotherapy intervention than the LT group. Conclusion: For patients with traumatic neck pain, high levels of PTSS are associated with poorer psychological outcomes but do not affect the outcomes of multimodal physiotherapy intervention.