Funding for this research was provided by:
Horizon 2020 Framework Programme (777090, 777090, 777090)
H2020 European Research Council (689043, 689043, 689043)
NTNU Norwegian University of Science and Technology
Received: 18 May 2021
Accepted: 22 August 2022
First Online: 1 September 2022
: The authors declare that they have no competing interests.
: Ethics approvals were obtained for both <scp>self</scp>BACK and Back-UP before the collection of data. Approval for the <scp>self</scp>BACK trial was obtained from the Regional Ethics Committees for Medical and Health Research Ethics in Denmark (S-20182000-24) and Norway (2018/791). Approval from the data protection agency was obtained for Denmark (18/17955) through the University of Southern Denmark. For the Back-UP trial, approval was obtained from the Regional Committee for Medical and Health Research Ethics in Central Norway (Ref. 2019/64084). All participants provided written informed consent that their data collected as part of the trial can be used in research. No formal ethical approval was required for data collected by Roessingh Center of Rehabilitation since according to the Dutch law (Medical Research Involving Human Subjects Act), the nature of this research did not require formal medical ethical approval. Access to the data was granted by an employee of the Roessingh Center of Rehabilitation who is responsible for managing the dataset, with the verbal agreement of not sharing the data with anyone else. At the beginning of the questionnaire, patients were asked whether they agreed to the use of their data for research purposes (informed consent), where they had to tick a checkbox if they agreed.
: All participants provided written informed consent acknowledging that their data may be used in research, results of which may be made public, but personal identifiable information will not be disclosed in any publication.