To share or not to share data: how valid are trials evaluating first-line ovulation induction for polycystic ovary syndrome? Esmee M. Bordewijk 1,2 , Rui Wang 1 , Madelon van Wely 2 , Michael F. Costello 3 , Robert J. Norman 4,5 , Helena Teede 6 , Lyle C. Gurrin 7 , Ben W. Mol 1 , and Wentao Li 1, * 1 Department of Obstetrics and Gynecology, Monash University, Clayton, Australia 2 Centre for Reproductive Medicine, Amsterdam UMC, Amsterdam, The Netherlands 3 School of Women’s and Children’s Health, The University of New South Wales, Sydney, Australia 4 Robinson Research Institute, The University of Adelaide, Adelaide, Australia 5 Fertility SA, Adelaide, Australia 6 Monash Centre for Health Research and Implementation, Monash University, Clayton, Australia 7 Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Australia *Correspondence address. Department of Obstetrics and Gynecology, Monash University, Clayton, Australia. E-mail: wentao.li@mona- sh.edu https://orcid.org/0000-0001-8980-0909 Submitted on April 27, 2020; resubmitted on June 25, 2020; editorial decision on June 30, 2020 TABLE OF CONTENTS ................................................................................................................................ • Introduction • Methods Inclusion of RCTs Data extraction Data synthesis Quality assessments • Results Inclusion of RCTs Characteristics of RCTs Quality of evidence of shared and non-shared IPD RCTs • Discussion BACKGROUND: In our recent individual participant data (IPD) meta-analysis evaluating the effectiveness of first-line ovulation induction for polycystic ovary syndrome (PCOS), IPD were only available from 20 studies of 53 randomized controlled trials (RCTs). We noticed that the summary effect sizes of meta-analyses of RCTs without IPD sharing were different from those of RCTs with IPD sharing. Granting access to IPD for secondary analysis has implications for promoting fair and transparent conduct of RCTs. It is, however, still common for authors to choose to withhold IPD, limiting the impact of and confidence in the results of RCTs and systematic reviews based on aggregate data. OBJECTIVE AND RATIONALE: We performed a meta-epidemiologic study to elucidate if RCTs without IPD sharing have lower quality and more methodological issues than those with IPD sharing in an IPD meta-analysis evaluating first-line ovulation induction for PCOS. SEARCH METHODS: We included RCTs identified for the IPD meta-analysis. We dichotomized RCTs according to whether they provided IPD (shared group) or not (non-shared group) in the IPD meta-analysis. We restricted RCTs to full-text published trials written in English. V C The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com Human Reproduction Update, Vol.26, No.6, pp. 929–941, 2020 Advance Access Publication on September 16, 2020 doi:10.1093/humupd/dmaa031 Downloaded from https://academic.oup.com/humupd/article/26/6/929/5906174 by guest on 01 April 2021