Trait anxiety mediates the effect of stress exposure on post-traumatic stress disorder and depression risk in cardiac surgery patients

Background: Post-traumatic stress disorder (PTSD) and depression are common after cardiac surgery. Lifetime stress exposure and personality traits may influence the development of these psychiatric conditions. Methods: Self-reported rates of PTSD and depression and potential determinants (i.e., trait anxiety and stress exposure) were established 1.5 to 4 years after cardiac surgery. Data was available for 1125 out of 1244 (90.4%) participants. Multivariable linear regressions were conducted to investigate mediating and/ or moderating effects of trait anxiety on the relationship between stress exposure, and PTSD and depression. Pre-planned subgroup analyses were performed for both sexes. Results: PTSD and depression symptoms were present in 10.2% and 13.1% of the participants, respectively. Trait anxiety was a full mediator of the association between stress exposure and depression in both the total cohort and female and male subgroups. Moreover, trait anxiety partially mediated the relationship between stress exposure and PTSD in the full cohort and the male subgroup, whereas trait anxiety fully mediated this relationship in female patients. Trait anxiety did not play a moderating role in the total patient sample, nor after stratification on gender. Limitations: The unequal distribution of male (78%) and female patients (22%) might limit the generalizability of our findings. Furthermore, risk factors were investigated retrospectively and with variable follow-up time. Conclusions: In cardiac surgery patients, trait anxiety was found to be an important mediator of postoperative PTSD and depression. Prospective research is necessary to verify whether these factors are reliable screening measures of individuals' vulnerability for psychopathology development after cardiac surgery.