Fig. 2.
Interactive modifying associations of SDNN and post-injury surgical intervention status with posttraumatic stress disorder (PTSD) at 3, 6, 12, and -24months in patients with physical injuries. aInteractive modifying associations of SDNN and post-injury surgical interventions on PTSD onset were estimated using multinomial logistic regression; and bodds ratios (95% confidence intervals) were calculated using binary logistic regression for higher (> 22 ms) vs. lower (≤ 22 ms) SDNN at baseline on development of PTSD at each follow-up, adjusted for age, sex, education, previous psychiatric disorders, previous traumatic events, number of physical disorders, scores on Hamilton Depression Rating Scale, and heart rate. *P < 0.05; †P < 0.01.