Els van Meijel

74 Chapter 4 | Results of a 2–4-year follow-up study analysis to examine the association between multiple variables and PTSD and PTSS, and we would have accounted for the variance in the time between T1 and T2, which ranged between 2 and 4 years. However, the number of children with PTSD or PTSS in our sample was too low to perform this analysis (Peduzzi et al., 1996). Fourth, due to the range in ages of children, we used two different PTSS self-report measures, CRIES and IES-R. However, algorithms to transform raw scores into standardized scores are not available. Hence, we could not combine continuous data from these instruments and perform multivariate linear regression. Fifth, due to the acute situation after an accident, a retrospective pain rating was used. This increases the chance of unreliable pain ratings (Lewandowski, Palermo, Kirchner, & Drotar, 2009; van Meijel et al., 2019). Sixth, since the T1 information was available to the interviewers, they were not blinded to diagnoses and scores. To account for the possible implications of this aspect of the study, the interpretation of the results was performed in cooperation with an independent clinical statistician. The most important strength of this study is the much longer-term follow-up than in prior studies and the possibility to compare the results with short-term findings. Second, in addition to psychological aspects, we included acute pain and physical condition in our study. Third, we used parent and child-informed interviews as well as validated child questionnaires, thus increasing completeness and reliability of the information. Finally, although the sample size is relatively small, a 61% response for a long-term follow-up study is good. The results of our study can, therefore, make a valuable contribution to the overall knowledge of long-term consequences of accidental injury. Conclusions and clinical implications Our findings show that the long-term prevalence of PTSD in children and adolescents following accidents is comparable to the short-term prevalence. Over the long term, PTSD was related to a new traumatic event or to the initial accident. In our study, a small number of children completed trauma-focused psychotherapy after the accident. At follow-up they were still free of posttraumatic stress symptoms, in contrast to those who did not complete psychotherapy. A substantial number of the participating children reported permanent physical impairment, ongoing