Study question: Do the infertility core outcome set and standardized definitions affect the outcome selection for randomized controlled trials, and what aspects should be further improved in the future?
Summary answer: Intrauterine pregnancy demonstrated the highest uptake level, whereas others were low, especially in neonatal outcomes; as time progresses, the sample size increases, and with prospective registration, the consistency of outcome reporting improves significantly.
What is known already: The infertility core outcome set aims to standardize outcome reporting and prevent selective reporting bias; however, there is a paucity of research evaluating its actual adoption, which is crucial for the timely promotion of transparency, standardization, adjustment of development strategies, and efficient resource utilization.
Study design, size, duration: This cross-sectional study included 1534 eligible randomized controlled trial registrations for infertility in 16 registries from March 17, 2004, to October 8, 2023 based on registry entries.
Participants/materials, setting, methods: A total of 4192 infertility-related studies from November 1, 1999, to October 8, 2023, were retrieved in the World Health Organization’s International Clinical Trials Registry Platform. Finally, 1534 randomized controlled trial registrations were selected and divided into the four period groups. Period, target sample size, prospective registration, and blinding were potential influencing factors. The consistency of outcomes, definitions, and standardized denominators of randomized controlled trial registry entries with the recommendations of the infertility core outcome set were the main outcomes. Independent retrieval, screening, data extraction, and consistency evaluations by two assessors and expert consultations were conducted to assess uptake and potential influencing factors of the infertility core outcome set in randomized controlled trials involving infertile patients undergoing in vitro fertilization.
Main results and the role of chance: Results reveal that reporting level in the pregnancy domain was significantly higher than that in the neonatal domain (13.5% vs. 5.5%). Intrauterine pregnancy (66.9%), live birth (26.9%), and miscarriage (26.7%) had relatively high uptake levels. Uptake of most core outcomes and domains as well as the total number of reported core outcomes were influenced positively by periods, target sample sizes, and prospective registrations. Multivariable analyses supported the above finding. Reasons responsible for the results may be attributed to the lack of effective propaganda measures, as well as the limited researcher awareness regarding this core outcome set.
Limitations, reasons for caution: Some results in this study may have been influenced by the subjective judgment of the evaluators due to the complexity of the information in registries.
Wider implications of the findings: Achievements related to infertility core outcomes are continually evolving, which enhances the consistency of outcome reporting. Uptake of most outcomes or domains tends to be growing but is not yet ideal. The key to promoting uptake is to form a consensus by synthesizing a large number of existing research achievements, further expand and publicize the core outcome set, cooperate with the registries, and foster multidisciplinary cooperation.
Contributors: Wenqiang Li1,2, Nanxi Jia1,3, Hongbin Chi4, Siyan Zhan1,2,3, Lin Zeng1,2*
Affiliations/Organisations:
1Research Center of Clinical Epidemiology, Peking University Third Hospital, 49 Huayuan North Road, Haidian District, Beijing 100191, China;
2Key Laboratory of Epidemiology of Major Diseases (Peking University), Ministry of Education, Beijing 100191, China;
3School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China;
4Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, 49 Huayuan North Road, Haidian District, Beijing 100191, China.
*the principal investigator or supervisors
Disease Category: Pregnancy & childbirth
Disease Name: Infertility
Age Range: 18 - 120
Sex: Female
Nature of Intervention: Any
- Researchers
- Statisticians
- COS uptake study
- Other
- Survey
Independent retrieval, screening, data extraction, and consistency evaluations by two assessors and expert consultations