Uptake of core outcome sets by clinical trialists publishing in major medical journals: Protocol [version 2; peer review: 2 approved] oleh Karen Matvienko-Sikar, Kerry Avery, Jane Blazeby, Karen Hughes, Pamela Jacobsen, Jamie Kirkham, Jan Kottner, Katie Mellor, Ian Saldanha, Valerie Smith, Caroline B. Terwee, Paula R. Williamson, MRC-NIHR TMRP Outcomes Working Group Core Outcome Set Theme