Core Outcome Set for Studies on Cardiac Disease in Pregnancy (COSCarP): An International Delphi Consensus Study.

Background: Outcome reporting in cardio-obstetrics studies is inconsistent. The objective of the COSCarP study (Core Outcome Set on Cardiac Diseases in Pregnancy) was to develop a core outcome set through international consensus and harmonize outcome reporting in cardio-obstetrics studies.

Methods: We conducted a multimethod study between February 2021 and April 2023 that included an online 2-round Delphi survey, 3 small group discussions and a consensus meeting with health service users (people with lived experience of pregnancy and heart disease) and health care professionals.

Results: A total of 110 participants (22 health service users and 88 health care professionals) from 13 countries in Africa, Asia, Europe, and North America scored 71 candidate items obtained through literature reviews and qualitative interviews. Participants identified 12 core outcomes and 12 core reporting checklist items (which may not always represent outcomes) for inclusion in all cardio-obstetrics studies. Core outcomes included: maternal mortality, cardiac arrest, cerebrovascular events, heart failure, arrhythmias requiring treatment or change in treatment, thromboembolism, syncope, maternal intensive care unit admission, cardiovascular interventions, perinatal loss (miscarriage, stillbirth, neonatal death), severe neonatal morbidity, and prolonged neonatal intensive care unit admission. Reporting checklist items included: hypertensive disorders, major bleeding, anesthetic complications, adverse reactions, labor and birth details, maternal hospitalization and re-admissions, treatment compliance, fetal growth restriction, congenital malformations, gestational age at birth, and nonsevere neonatal morbidity. Participants also identified 7 condition-specific outcomes and 7 other patient-important outcomes, which may be challenging to measure in all studies and should be reported when feasible and relevant.

Conclusions: The COSCarP study has identified core outcomes, reporting checklist items, and patient-important outcomes, which researchers are encouraged to measure and report in future cardio-obstetrics studies. Widespread use of the COSCarP checklists could support data harmonization, enable meaningful comparisons between studies, facilitate meta-analyses, and ensure that future guidelines incorporate patient-important outcomes while making clinical practice recommendations.