"You can't always get what you want": from doctrine to practicability of study designs for clinical investigation in endometriosis

Background: Patients, now generally well informed through dedicated websites and support organizations, are beginning to look askance at clinical experimentation. We conducted a survey investigation to verify whether women with endometriosis would still accept to participate in a randomized controlled trial (RCT) on treatment for pelvic pain. Methods: A total of 500 patients consecutively self-referring to an academic outpatient endometriosis clinic, were asked to compile two questionnaires focused on hypothetical comparisons between a new drug and a standard drug, and between medical and surgical treatment, for endometriosis-associated pelvic pain. The main outcome measure was the percentage of patients willing to participate in a theoretical RCT. Results: A total of 239 (48 %) women would decline participation in a comparative study on a new drug and a standard drug, as 204 (41 %) would prefer the former medication, and 35 (7 %) the latter. Fifty women (10 %) would participate in a RCT, but only 24 (5 %) would accept blinding. The most frequently chosen option was the patient preference trial (211; 42 %). No significant differences were observed in demographic and clinical characteristics between the 50 women who would accept and the 450 who would decline to be enrolled in a RCT. A total of 229 women (46 %) would decline participation in a comparative study on medical versus surgical treatment, as 186 (37 %) would prefer pharmacological therapy and 43 (9 %) a surgical procedure. Only 11 (2 %) women would participate in such a RCT. More than half of the women (260; 52 %) selected the patient preference trial. No significant variations in distributions of answers were observed between women who did or did not undergo a previous surgical procedure. Conclusion: Only a small minority of the women included in our study sample would accept randomization, and even less so blinding. Patient preference appears to play a central role when planning interventional trials on endometriosis-associated pelvic pain. Adequately designed observational analytic studies could be considered when recruitment in a RCT appears cumbersome.