Participant recruitment
Inclusion took place between January 2019 and October 2020 in six Dutch academic hospitals (23.7% of the patients) and eight non-academic hospitals (46.7%) and also by the Dutch and Belgian endometriosis foundation (29.6%). Women who were interested could visit the website (www.endokeuze.com) for information about the study. It was especially noted that only women with DE and bowel involvement could participate in this study. Women willing to participate had to pass three inclusion questions, which are commonly used and accepted in endometriosis questionnaire studies (15) (16) (17). For this DCE only women with surgically or radiologically (ultrasound and/or MRI) diagnosed DE with bowel involvement, prior to a treatment decision and currently not in any fertility treatment trajectory could participate. Women could not see which answer would in- or exclude them. The first question was: “Do you have deep endometriosis with bowel involvement, which is diagnosed by a doctor by ultrasound, MRI or surgery?” Patients who answered this with ‘yes’ received a second question; “Are you prior to a treatment choice with medication or surgery?” Patients who answered this with ‘yes’ received a final question; “Are you currently in a trajectory to become pregnant (e.g. hormonal treatment for ovulation induction, IVF)?” Patients who answered these questions with ‘no’ were included in the study prior to a digital informed consent form. Patients who did not meet the inclusion criteria, were acknowledged for their interest in the study, but could not further participate. Further exclusion criteria were low health literacy, this was tested with three questions (18).
Further exclusion criteria were low health literacy, this was tested with three questions (18). We excluded patients who indicated to always have difficulties with understanding medical information about their disease and treatment, always need help with reading information about their disease and treatment and have no confidence at all in filling in medical forms. Furthermore, patients with no informed consent, patients who did not complete the 10 DCE questions, patients who completed the whole survey in ≤ 10 minutes time (this ‘too fast’ threshold was set after the pilot) and patients who gave the same answer on all questions in the first section of the survey and DCE, were excluded. A total of 641 patients started the survey (Supplementary table S1), 141 patients were excluded at inclusion question one (no DE with bowel involvement), 152 patients were excluded at inclusion question two (not prior to a treatment decision), 53 patients were excluded at inclusion question three (patients in fertility treatment). A total of 91 patients who met the inclusion criteria but stopped after reading the information were also excluded, five patients with no informed consent were excluded. One patient who filled in the same answer at all questions (survey fatigue), 24 patients who did not complete the DCE task, three patients with poor health literacy were excluded. One patient indicated to always have difficulties with understanding medical information about her disease and treatment, one patient always needed help with reading information about her disease and treatment and one patient who had no confidence at all in filling in medical forms. Furthermore, two patients were excluded who completed the DCE within 10 minutes. This resulted in 169 patients who met all inclusion criteria (26.4% of the initial amount of patients who started the survey).