UMMS Affiliation

Department of Population and Quantitative Health Sciences

Publication Date


Document Type

Letter to the Editor


Digestive System Diseases | Gastroenterology | Research Methods in Life Sciences | Therapeutics


Dear Editor, In their network meta-analyses (NMAs) of treatments for ulcerative colitis (UC), Singh et al1 did not take into account a complication associated with studies that re-randomized patients for the maintenance phase: differential carryover effects from induction can bias the results. In those studies, patients who responded to induction were re-randomized to maintenance treatments that included placebo. If, however, carryover effects from induction differ substantially among active treatments, the effects of those treatments, relative to placebo, are not comparable.


Ulcerative Colitis, treatment, network meta-analyses, pharmacotherapies

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© 2020 by the AGA Institute. This article is available under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed.

DOI of Published Version



Naessens D, Cameron C, Hoaglin DC. Network Meta-Analysis of Ulcerative Colitis Pharmacotherapies: Carryover Effects from Induction and Bias of the Results. Clin Gastroenterol Hepatol. 2020 Oct 13:S1542-3565(20)31428-2. doi: 10.1016/j.cgh.2020.10.016. Epub ahead of print. PMID: 33065309. Link to article on publisher's site

Journal/Book/Conference Title

Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association

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PubMed ID


Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.