eprintid: 10175670
rev_number: 6
eprint_status: archive
userid: 699
dir: disk0/10/17/56/70
datestamp: 2023-08-24 13:08:11
lastmod: 2023-08-24 13:08:11
status_changed: 2023-08-24 13:08:11
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Riley, Richard D
creators_name: Ensor, Joie
creators_name: Hattle, Miriam
creators_name: Papadimitropoulou, Katerina
creators_name: Morris, Tim P
title: Two-stage or not two-stage? That is the question for IPD meta-analysis projects
ispublished: inpress
divisions: UCL
divisions: B02
divisions: D65
divisions: J38
keywords: individual participant data (IPD), meta-analysis, one-stage approach, two-stage approach
note: © 2023 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/).
abstract: Individual participant data meta-analysis (IPDMA) projects obtain, check, harmonise and synthesise raw data from multiple studies. When undertaking the meta-analysis, researchers must decide between a two-stage or a one-stage approach. In a two-stage approach, the IPD are first analysed separately within each study to obtain aggregate data (e.g., treatment effect estimates and standard errors); then, in the second stage, these aggregate data are combined in a standard meta-analysis model (e.g., common-effect or random-effects). In a one-stage approach, the IPD from all studies are analysed in a single step using an appropriate model that accounts for clustering of participants within studies and, potentially, between-study heterogeneity (e.g., a general or generalised linear mixed model). The best approach to take is debated in the literature, and so here we provide clearer guidance for a broad audience. Both approaches are important tools for IPDMA researchers and neither are a panacea. If most studies in the IPDMA are small (few participants or events), a one-stage approach is recommended due to using a more exact likelihood. However, in other situations, researchers can choose either approach, carefully following best practice. Some previous claims recommending to always use a one-stage approach are misleading, and the two-stage approach will often suffice for most researchers. When differences do arise between the two approaches, often it is caused by researchers using different modelling assumptions or estimation methods, rather than using one or two stages per se.
date: 2023-08-22
date_type: published
publisher: Wiley
official_url: https://doi.org/10.1002/jrsm.1661
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2046642
doi: 10.1002/jrsm.1661
lyricists_name: Morris, Timothy
lyricists_id: TNMOR17
actors_name: Morris, Timothy
actors_id: TNMOR17
actors_role: owner
funding_acknowledgements: MR/V038168/1 [Medical Research Council & National Institute for Health and Care Research]; [National Institute for Health and Care Research Birmingham Biomedical Research Centre]; MC_UU_00004/07 [UKRI Medical Research Council]; MC_UU_00004/06 [UKRI Medical Research Council]
full_text_status: public
publication: Research Synthesis Methods
event_location: England
citation:        Riley, Richard D;    Ensor, Joie;    Hattle, Miriam;    Papadimitropoulou, Katerina;    Morris, Tim P;      (2023)    Two-stage or not two-stage? That is the question for IPD meta-analysis projects.                   Research Synthesis Methods        10.1002/jrsm.1661 <https://doi.org/10.1002/jrsm.1661>.    (In press).    Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10175670/1/2023%20-%20Riley%20-%20two%20stage%20or%20not%20two%20stage%20-%20research%20syn%20meth.pdf