(591) A Core Outcome Set for studies on Vasa Previa (COVasP): an international consensus study

There is little consistency in how outcomes are measured and reported across screening, diagnostic, and management studies of Vasa Previa (VP). Our objective was to develop a core outcome set for diagnostic and management studies of VP.

Study Design:

This was an international Delphi consensus study, a part of the Core Outcome set for studies on Vasa Previa (COVasP) project. Previously, 67 outcomes were identified from interviews and literature reviews. Health service users (HSUs) and healthcare professionals (HCPs) from around the world were asked to participate in 2 rounds of online Delphi surveys, virtual small group meetings, and a virtual consensus meeting to finalize the core outcome set.

Results: A total of 115 HSUs and 89 HCPs from 23 countries participated in the Delphi survey, while 8 HSUs and 11 HCPs participated in virtual small group sessions. From these discussions, core outcomes were identified for all VP studies, such as fetal/neonatal survival, fetal/neonatal blood loss from rupture of fetal vessels, gestational age at birth, and severe neonatal morbidity. Others were deemed relevant only where screening was routinely performed (time interval between antepartum bleeding and birth) or not performed (mode of birth, neonatal intensive care unit admission and rupture of membranes).  Process measures, intermediary events, and outcomes not specific to VP studies were excluded. Following a final consensus meeting, the number of core outcomes and categorizations were ratified. Outcomes not identified as core were assigned categories such as: important but not core, minimal data items, and clinical practice recommendations.

Conclusion: This international consensus study identified core outcomes to be measured and reported in published studies on VP, in addition to other important data items to be incorporated into future research and clinical practice. This will enable harmonization of outcome reporting and measurement, facilitating appropriate meta-analyses and the drawing of meaningful conclusions to inform clinical practice and health policy.