Outcome reporting in cardio-obstetrics studies: A systematic review

Abstract

Background

Although considerable variation in the reporting and definition of outcomes in cardio-obstetrics studies is acknowledged, the extent of this variation has not been documented. The primary objective of this systematic review was to highlight this variation and inform the development of a Core Outcome Set for studies on Cardiac disease in Pregnancy (COSCarP).

Methods

Medline, Embase, Web of Science and Cochrane Central databases were searched from 1980 to 2018 to identify all English-language publications on pregnancy and heart disease. Title/abstract screening and data extraction which included details on the study, patient population, and all reported outcomes, was performed in duplicate by 2 reviewers. As the aim of the review was to identify variation in outcome reporting, risk-of-bias assessment was not performed. The study protocol was registered on PROSPERO (CRD42016038218).

Results

The final analysis included 422 cardio-obstetric studies. Maternal mortality or survival were reported in 232/422 studies, with inconsistency in terms of cause of death (all-cause [n = 65], cardiac [n = 55] or obstetric [n = 10]) or timeframe (ranging from in-hospital mortality [n = 11] to mortality 5 years following pregnancy). In 95/232 (41%) studies, the cause and timeframe were not specified. Similar inconsistencies in reporting and definitions were noted for outcomes such as heart failure (n = 298), perinatal loss (n = 296), fetal growth (n = 221), bleeding (n = 205), arrhythmias (n = 202), preterm birth (n = 191), thromboembolism (n = 153) and hypertensive disorders (n = 122). Functioning / life-impact and adverse effects of treatment were sparingly reported in published cardio-obstetric studies.

Conclusions

This systematic review hopes to create awareness among cardio-obstetrics teams about the inconsistencies in reporting and defining outcomes which makes it difficult to compare studies and perform meta-analyses. COSCarP which is being developed through international consensus between patients and care-providers will provide cardio-obstetrics teams with a minimal set of outcomes to be reported in future cardio-obstetrics studies.