Article History
Received: 20 June 2017
Accepted: 29 May 2018
First Online: 30 June 2018
Ethics approval and consent to participate
: The local institutional review board (the Medical Ethics Committee of the University Medical Center Groningen) has reviewed the study protocol and waived further need for approval, because this study did not fall within the scope of the Dutch Medical Research with Human Subjects Law (Wet Medisch-wetenschappelijk Onderzoek met mensen, WMO). The study was performed in compliance with the principles outlined in the Declaration of Helsinki on ethical principles for medical research involving human subjects. Patients who were eligible to participate received a letter with the questionaires which informed them about the purpose of the study. The patients who gave their informed consent returned the letter and the corresponding questionaires.
: The authors declare that they have no competing interests.
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