PT  - JOURNAL ARTICLE
AU  - Schandelmaier, Stefan
AU  - Briel, Matthias
AU  - Varadhan, Ravi
AU  - Schmid, Christopher H.
AU  - Devasenapathy, Niveditha
AU  - Hayward, Rodney A.
AU  - Gagnier, Joel
AU  - Borenstein, Michael
AU  - van der Heijden, Geert J.M.G.
AU  - Dahabreh, Issa J.
AU  - Sun, Xin
AU  - Sauerbrei, Willi
AU  - Walsh, Michael
AU  - Ioannidis, John P.A.
AU  - Thabane, Lehana
AU  - Guyatt, Gordon H.
TI  - Development of the Instrument to assess the Credibility of Effect Modification Analyses (ICEMAN) in randomized controlled trials and meta-analyses
AID  - 10.1503/cmaj.200077
DP  - 2020 Aug 10
TA  - Canadian Medical Association Journal
PG  - E901--E906
VI  - 192
IP  - 32
4099  - http://www.cmaj.ca/content/192/32/E901.short
4100  - http://www.cmaj.ca/content/192/32/E901.full
SO  - CMAJ2020 Aug 10; 192
AB  - BACKGROUND: Most randomized controlled trials (RCTs) and meta-analyses of RCTs examine effect modification (also called a subgroup effect or interaction), in which the effect of an intervention varies by another variable (e.g., age or disease severity). Assessing the credibility of an apparent effect modification presents challenges; therefore, we developed the Instrument for assessing the Credibility of Effect Modification Analyses (ICEMAN).METHODS: To develop ICEMAN, we established a detailed concept; identified candidate credibility considerations in a systematic survey of the literature; together with experts, performed a consensus study to identify key considerations and develop them into instrument items; and refined the instrument based on feedback from trial investigators, systematic review authors and journal editors, who applied drafts of ICEMAN to published claims of effect modification.RESULTS: The final instrument consists of a set of preliminary considerations, core questions (5 for RCTs, 8 for meta-analyses) with 4 response options, 1 optional item for additional considerations and a rating of credibility on a visual analogue scale ranging from very low to high. An accompanying manual provides rationales, detailed instructions and examples from the literature. Seventeen potential users tested ICEMAN; their suggestions improved the user-friendliness of the instrument.INTERPRETATION: The Instrument for assessing the Credibility of Effect Modification Analyses offers explicit guidance for investigators, systematic reviewers, journal editors and others considering making a claim of effect modification or interpreting a claim made by others.