Core Outcome Measures in Effectiveness Trials

Variation in hyperemesis gravidarum definition and outcome reporting in randomised clinical trials: a systematic review

General Information

BACKGROUND: Hyperemesis gravidarum (HG) is a common cause of hospital admission in early pregnancy. There is no international consensus on the definition of HG, or on outcomes that should be reported in trials. Consistency in definition and outcome reporting is important for the interpretation and synthesis of data in meta-analyses. OBJECTIVE: We aimed to identify which HG definitions and outcomes are currently in use in trials. SEARCH STRATEGY: We searched the following sources: (1) Cochrane Central Register of Controlled Trials, (2) Embase and (3) Medline for published trials and the WHO-ICTRP database for ongoing trials (27-Ocotber-2017) SELECTION CRITERIA: All randomised clinical trials reporting on any intervention for HG were eligible. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial eligibility and extracted data on HG definition and outcomes. RESULTS: We included 31 published trials reporting data from 2511 women and 3 ongoing trials with a planned sample size of 360 participant. We identified 11 definition items. Most commonly used definition items were vomiting (34 trials) and nausea (30 trials We identified 34 distinct outcomes. Most commonly reported outcomes were vomiting (29 trials), nausea (26 trials), need for hospital treatment (14 trials) and duration of hospital (re)admission(s) (14 trials). CONCLUSION: There is substantial variation of HG definition and outcome reporting in trials. This hampers meaningful aggregation of trial results in meta-analysis and implementation of evidence in guidelines. To overcome this, international consensus on a definition and a core outcome set for HG trials should be developed. This article is protected by copyright. All rights reserved.

Koot, M. H. Boelig, R. C. van 't Hooft, J. Limpens, J. Roseboom, T. J. Painter, R. C. Grooten, I. J.


Further Study Information

Funding source(s):

Health Area

Disease Category
Pregnancy & childbirth

Disease Name
Hyperemesis gravidarum

Target Population

Age Range


Nature / type of Intervention


Systematic review

Stakeholders Involved


Study Type

Systematic review of outcomes measured in trials

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