PT - JOURNAL ARTICLE AU - Buch, Maya H AU - Maksymowych, Walter P AU - Boers, Maarten TI - Managing the selection of placebo group switched to experimental treatment group in post-randomised controlled trial extension studies AID - 10.1136/annrheumdis-2021-221775 DP - 2022 Jan 12 TA - Annals of the Rheumatic Diseases PG - annrheumdis-2021-221775 4099 - http://ard.bmj.com/content/early/2022/01/12/annrheumdis-2021-221775.short 4100 - http://ard.bmj.com/content/early/2022/01/12/annrheumdis-2021-221775.full