Els van Meijel

62 Chapter 4 | Results of a 2–4-year follow-up study Methods Participants and procedures For reasons of brevity and readability, we decided to use one term for the participants in this manuscript, instead of specifying various age groups of children, adolescents and young adults. Since parents were also involved in the study to report about their children, we considered it appropriate to use “parents and children”. From 2008 to 2010, we conducted a study in which we evaluated the Screening Tool for Early Predictors of PTSD (STEPP; Winston et al., 2003), a screening instrument to determine the risk of PTSD in children who had been injured due to accidental trauma (van Meijel et al., 2015). The STEPP study concluded with the assessment of PTSD 3 months after the accident (T1). The follow-up assessment was not scheduled in the design of the initial study. In 2012, we had the opportunity to conduct a follow-up assessment but we were limited in time. Despite resulting variability due to the range of 2 to 4 years in follow-up, we decided to use this opportunity. For the current follow-up study, we approached the families (the children and one of their parents) who had participated in the first study and we assessed child PTSD 2 to 4 years after the accident (T2). The families received a letter in which the follow-up study was announced, including an explanation of the purpose of the study. Subsequently, we contacted the families via telephone. They were invited to participate in a telephone interview and to complete one questionnaire sent by email. Consent was given either in writing (by email) or during the initial telephone conversation (in which case this part of the conversation was audiotaped). The current study was approved by the Medical Ethical Committees of both hospitals of the Amsterdam UMC in Amsterdam, the Netherlands, and was performed from October 2012 to March 2013. Of the 147 participating families in the first study, 90 families (61%) participated in the follow-up study. See Figure 4.1, Flowchart of participation. Of the initial group, 33 families could not be reached (4 telephone numbers were no longer in use and 29 did not answer the call) and 24 declined to participate. Reasons for declining participation were serious medical and/or psychological problems (3 families) and lack of time or no interest (21 families). Of this group of 90 participants, 62 (69%) had been involved in a