Wouter Leclercq

Chapter 10 160 METHODS Study design and participants We did a multicentre, single-blind, randomised controlled trial at seven teaching hospitals in the Netherlands. We recruited potential study participants from the surgical waiting lists of these teaching hospitals. We judged patients eligible for the study if they were aged 18-75 years and scheduled for laparoscopic adnexal surgery, laparoscopic or open hernia inguinal surgery, or laparoscopic cholecystectomy. Exclusion criteria included surgery without curative intent or with additional radiotherapy or chemotherapy, deep infiltrating endo metriosis, (ectopic) pregnancy, adnexal surgery because of pelvic inflammatory disease or tubal ovarian abscess, a combination of several surgical procedures, and severe comorbidity that might complicate the postoperative course. We defined these exclusion criteria because the intervention would not be applicable for these patients. 10,11 Two further exclusion criteria were an inability to understand information about the research and insufficient understanding or ability to fill in (Dutch) questionnaires. We defined these two exclusion criteria because patients meeting these criteria would not be able to participate in the study. We obtained written informed consent from all patients who met the inclusion criteria and were willing to participate. The study was approved by the local medical ethics committee of the VU University Medical Centre (registration number 2014.301) and by the institutional review boards of all participating hospitals. The quality committee of the Amsterdam Public Health research institute reviewed and approved the study. The study protocol has been published. 9 Randomisation and masking After informed consent had been signed we asked participants to complete a baseline questionnaire (T0) in the 4-week period before surgery. Randomisation to either the intervention or control group took place directly after the baseline questionnaire had been completed. Randomisation was done in a 1:1 ratio using computer-generated lists and was stratified by hospital, sex, and surgical procedure using a block size of two. A researcher who was independent from the recruitment process and data analyses did the randomisation process. Immediately after randomisation, participants received an email that was generated automatically, containing a link to one of the two care programmes (intervention or control). Participants were unaware of the study hypothesis: they knew they were allocated to one of two care programmes, but they did not know that one programme was developed as an intervention and the other as a control. The researcher who did the analyses was masked to the random allocation throughout. Health-care providers were not masked to the allocation.