Background: Over the last five years, we have observed an increase in the registration of projects aiming to develop core outcome sets (COS) and address the inconsistencies in outcome reporting. The trend is particularly apparent in the area of women’s and newborns' health research. A recent systematic review showed that despite there being 46 registered COS, there are only 20 systematic reviews in the existing literature that evaluate variation in outcomes. These systematic reviews described the observed variation in outcome reporting as ‘considerable’, but provided no further details.
Objective: We aim to identify systematically the number of registered COS with published (or registered) reviews of the literature in the area of women’s and newborns' health and evaluate how their authors defined variation in outcome reporting.
Methods: We will perform a systematic review of the literature (MEDLINE) and relevant registers (Core Outcome Measures in Effectiveness Trial [COMET] initiative and the Core Outcomes in Women’s and Newborn Health [CROWN] initiative). We will include systematic reviews of variation in outcome reporting, COS registry entries, COS protocols and published COS on the conditions affecting women’s and newborns' health. For each study, we will record funding status, the timing of the publication or COS registration, whether the review was part of COS development or triggered it, the number of outcomes reported by the review, and authors’ results and conclusions regarding the degree of variation. We will tabulate the results and present them as frequencies.
Results and discussion: Inconsistent selection and reporting of outcomes in clinical studies is a serious hindrance to medical research and is an example of research waste. Hastily commenced COS development that has no real need consumes researchers' time and effort, and exacerbates the problem it intends to address. We will provide a detailed description of our findings and their implications for the evaluation of variation in outcome reporting and development of COSs. We intend to identify the most valuable method of presenting variation in outcome reporting for the future studies.