A core outcome set for future endometriosis research: an international consensus development study

Objective To develop a core outcome set for endometriosis. Design Consensus development study. Setting International. Population One hundred and sixteen healthcare professionals, 31 researchers, and 206 patient representatives. Methods Modified Delphi method and modified Nominal Group Technique. Results The final core outcome set includes three core outcomes for trials evaluating potential treatments for pain and other symptoms associated with endometriosis: overall pain, improvement in the most troublesome symptom, and quality of life. In addition, eight core outcomes for trials evaluating potential treatments for infertility associated with endometriosis were identified: viable intrauterine pregnancy confirmed by ultrasound, pregnancy loss including ectopic pregnancy, miscarriage, stillbirth, and termination of pregnancy, live birth, time to pregnancy leading to live birth, gestational age at delivery, birth weight, neonatal mortality, and major congenital abnormalities. Two core outcomes applicable to all trials were also identified: adverse events and patient satisfaction with treatment. Conclusions Using robust consensus science methods, healthcare professionals, researchers, and women with endometriosis have developed a core outcome set to standardise outcome selection, collection, and reporting across future randomised controlled trials and systematic reviews evaluating potential treatments for endometriosis.