Importance Vasa previa, although a rare condition affecting 0.46 per 1000 pregnancies, results in high rates of fetal and neonatal mortality and morbidity. Widespread use of a core outcome set and reporting checklist may enable data harmonization, enhance evidence synthesis, and ensure prioritization of patient-important outcomes in clinical practice, future research, and clinical practice guidelines.
Objective To develop a core outcome set for studies on vasa previa that includes perinatal screening, diagnosis, and management of vasa previa.
Design, Setting, and Participants This survey study involved a 2-round international and cross-disciplinary Delphi survey and virtual consensus meetings conducted between March 14, 2021, and October 4, 2022. Health care professionals (HCPs) and health service users (HSUs) were invited to participate in the development of the core outcome set.
Exposure Perinatal screening, diagnosis, and management of vasa previa.
Main Outcome and Measures Core outcomes and reporting checklist items for future studies on vasa previa were developed using Delphi surveys, small group discussions, and a consensus meeting.
Results An international group of 204 participants, comprising 115 HSUs and 89 HCPs representing 27 countries, rated 67 outcomes identified through a systematic review and qualitative interviews in a 2-round online Delphi survey. Through virtual small group discussions and a consensus meeting, 13 core outcomes were identified: pregnancy outcome (live birth, fetal loss [miscarriage or stillbirth], or neonatal death), severe neonatal morbidity, fetal/neonatal blood loss, neonatal intensive care unit admission for >24 hours, gestational age at birth, third trimester confirmation of vasa previa diagnosis, neurocognitive and developmental outcomes, mode of birth, maternal death or severe morbidity, maternal quality of life, duration of antepartum admission, and antepartum or peripartum hemorrhage. A 22-item reporting checklist was simultaneously developed to include important items in studies on vasa previa when possible and/or relevant.
Conclusions and Relevance The core outcome set and reporting checklist for vasa previa are hoped to encourage researchers to incorporate patient-important outcomes in future studies to enable data harmonization, improve evidence synthesis, and facilitate the development of clinical practice guidelines for this rare and highly lethal condition for which timely diagnosis and management may prevent fetal and maternal morbidity and mortality.
Tiffany Yeretsian, Nasrin Javid, Natasha Hirschhorn-Edwards, Rizwana Ashraf, Alisha Adams, John Kingdom, Rohan D’Souza
Disease Category: Pregnancy & childbirth
Disease Name: Vasa Previa
Age Range: 18 - 50
Sex: Female
Nature of Intervention: Any
- Charities
- Clinical experts
- Conference participants
- Consumers (caregivers)
- Consumers (patients)
- Epidemiologists
- Families
- Methodologists
- Patient/ support group representatives
- Policy makers
- Researchers
- COS for clinical trials or clinical research
- COS for practice
- Recommendations for outcome measures (measurement/how)
- Consensus meeting
- Delphi process
- Focus group(s)
- Systematic review
Stage 1) Identifying core outcomes:
a) Systematic review -
A systematic review of the study reports will catalogue outcomes and outcome measures. The following two questions will be addressed and considered the primary and secondary outcome of the review:
(1) What maternal, fetal, neonatal and obstetric outcomes have been reported in studies investigating the antenatal diagnosis and management of Vasa Previa in pregnant women?
(2) How have these reported outcomes been defined and/or measured? What is the outcome reporting quality [(using the MOMENT criteria (Harman, 2013)]?
Studies will be searched using the databases MEDLINE, EMBASE and Clinicaltrials.gov. All interventions and exposures will be included. Randomized or non-randomized studies, prospective and retrospective cohort studies, and systematic reviews will be included in the search. We will exclude letters to the editor, commentaries, editorials, case-control studies, case reports and case series with less than 5 cases reported, conference abstracts that do not describe clinical outcomes and reviews that do not contain original research.
Two reviewers will extract the following data using a piloted data extraction form: publication details, study design, study aim, number of participants, primary and secondary outcomes reported, definitions of reported outcomes, tools used to measure outcomes, rationale for outcome use and methods used to enhance quality of outcome measurement. Reviewers will independently assess the quality of reporting outcomes within each study. The extracted outcomes and measures will be grouped as maternal, fetal, neonatal or obstetric. The number of studies in each group, and the study’s reporting quality score will be reported.
b) Qualitative Patient Interviews: Patients will be recruited to take part in semi-structured interviews. Interview questions will be developed in consultation qualitative research experts in conjunction with patient representatives identified through the International Vasa Previa Association, and will be guided by the literature review. Thematic content analysis will identify potential core outcomes.
c) Outcome Inventory: A comprehensive inventory of outcomes identified by the literature review and qualitative patient interviews will be developed prior to entering into the Delphi process.
Stage 2) Determining core outcomes:
Delphi methodology: Patients, their family members and patient representatives as well as other stakeholders including clinicians involved in the care of these women (maternal-fetal medicine physicians, obstetricians, obstetric nurses, neonatologists, radiologists, family doctors, specialist midwives, obstetric anaesthesiologists), researchers, administrators, policy makers and guideline developers will be invited to participate in a process that assesses the extent of agreement (consensus measurement) and then resolves disagreement (consensus development). Repeated reflection and scoring will be encouraged, to increase the likelihood of stakeholder group convergence towards consensus core outcomes. If this is not achieved, a consensus group meeting will be convened.
Stage 3) Determining How Core Outcomes Should be Measured:
a) Quality Assessment: Once core outcomes have been agreed upon, an assessment framework (truth, discrimination, feasibility) will evaluate the quality of these potential outcome measures using recommendations set out by COSMIN (COnsensus-based Standards for the selection of health Measures and INstruments). This will include evaluating the studies by statistical method, methodological quality and generalizability of the results. High-quality outcome measures will then be incorporated into the core outcome set.
b) Stakeholder Consultation: Stakeholder feedback will be collated, reviewed, and incorporated into the finalised core outcome set prior to distribution.