A call to action for data definition standardisation and core outcome sets.

Abstract

Systematic reviews, which form the pinnacle of the ‘levels of evidence pyramid’, synthesise knowledge and serve to evolve evidence-based medical practice. Duffy and colleagues present a systematic review of maternal and offspring outcome reporting across 79 randomised controlled trials (RCTs) evaluating 55 various therapeutic interventions for pre-eclampsia. These RCTs reported 119 different outcomes (72 maternal and 47 offspring outcomes) for 31 615 maternal and 28 172 offspring participants. Surprisingly, some critical yet easily acquirable outcomes were often not reported: for example, maternal mortality and offspring mortality were reported in 14% and 35% of RCTs, respectively. Fewer than half of all RCTs reported maternal and offspring harm, only six RCTs reported childhood outcomes (with the longest duration of follow-up being 2 years), and three RCTs performed economic evaluations. Relatively recently, it has become apparent to researchers and clinicians that variation and heterogeneity in reported outcomes among related RCTs create impediments to aggregating data. This problem stems from several sources, including multiple potential definitions for a single outcome and from wide variations in reporting from the panoply of potential outcomes. For example, an RCT on the treatment of postpartum haemorrhage may define it as 500 mL for vaginal delivery and 1000 mL for caesarean delivery, whereas another may use a definition of 1000 mL in the first 24 hours, regardless of delivery mode. A study on interventions for pre-eclampsia may base the definition of severe pre-eclampsia upon the American Congress of Obstetricians and Gynecologists (ACOG), the UK National Institute for Health and Care Excellence (NICE), the International Society for the Study of Hypertension in Pregnancy (ISSHP), or other recognised, but essentially different, guidelines. Concerted efforts to standardize clinical definitions, such as ACOG's reVITALize campaign, are needed to improve outcome reporting and aggregate analysis in subsequent systematic reviews (Menard et al. Obstet Gynecol 2014;124:150–3). The COMET Initiative (Core Outcome Measures in Effectiveness Trials), formed in Liverpool in 2010, is a database focused on studies for the development and implementation of standardised core outcomes sets (COSs), which are determined by consensus methodology involving multiple stakeholders and contain the minimum number of variables deemed critically important to a topic (Williamson & Clarke Cochrane Database Syst Rev 2012;5:ED000041). The CROWN Initiative (Core Outcomes in Women's Health) aims to form a consortium to promote the development of COSs in our specialty (Khan BJOG 2014;121:1181–2). At present, three COSs are endorsed by CROWN (epilepsy in pregnancy, preterm birth prevention, and maternity care), with many others in development. One significant limitation of systematic reviews is the potentially short shelf life: one study reported that 23% of systematic reviews needed updating within 2 years of publication (Shojania et al. Ann Intern Med 2007;147:224–33). Data definition standardisation, implementation of COSs, and data sharing via repositories (Coady et al. N Engl J Med 2017;376:1849–58) should accelerate our ability to make timely systematic review updates and changes to best practice. So, let this be a call to action for collaborative efforts among researchers, publishers, guideline makers, grant-making agencies, insurers, and patient advocacy groups for a further focus on the development of data definition standardisation and COSs in obstetrics and gynecology research. None declared. Completed disclosure of interests form available to view online as supporting information. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.