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Volume 21, Number 1—January 2015
Online Report

Workshop on Use of Intravenous Immunoglobulin in Hand, Foot and Mouth Disease in Southeast Asia

Sokkosal Chea, Yi-bing Cheng, Kulkanya Chokephaibulkit, Tawee Chotpitayasunondh, H. Rogier van DoornComments to Author , Zen Hafy, Surinda Kawichai, Ching-Chuan Liu, Nguyen Tran Nam, Mong How Ooi, Marcel Wolbers, and Mei Zeng
Author affiliations: Angkor Hospital for Children, Siem Reap, Cambodia (S. Chea); Zhenzhou Children’s Hospital, Henan, China (Y. Cheng); Siriraj Hospital, Mahidol University, Bangkok, Thailand (K. Chokephaibulkit); Queen Sirikit National Institute of Child Health, Bangkok (T. Chotpitayasunondh); Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam (H.R. van Doorn, M. Wolbers); Family Health International 360, Bangkok (Z. Hafy, S. Kawichai); National Cheng Kung University, Tainan, Taiwan (C.-C. Liu); Children’s Hospital 2, Ho Chi Minh City (N.T. Nam); Sarawak General Hospital, Kuching, Sarawak, Malaysia (M.H. Ooi); Fudan University Children’s Hospital, Shanghai, China (M. Zeng)

Main Article

Table 2

Total required sample size for a 1:1 randomized trial designed to demonstrate noninferiority of placebo compared with IVIg at the 1-sided 2.5% significance level with 90% power*

Absolute risk of progression† Noninferiority margin Δ‡
5% 7.5% 10% 15%
15% 2,144 954 536 240
20% 2,690 1,196 674 300

*Sample sizes are total sample sizes (i.e., for both groups combined) but do not account for loss-to-follow-up or increases in sample size that would be required if formal interim analyses with stopping boundaries are planned. IVIg, intravenous immunoglobulin.
†Assumed to be identical for both groups.
‡The noninferiority margin Δ is the absolute risk increase in the placebo arm to be exclude with the trial. That is, if the assumptions are correct, the sample sizes above guarantees that we can reject the hypothesis that placebo increases the absolute risk by +Δ (or more) at the 1-sided 2.5% significance level with 90% power. (Or, equivalently, the sample sizes above guarantee a probability of 90% that the 2-sided 95% CI for the absolute risk difference excludes an excess risk of +Δ, at worst, in the placebo arm.)

Main Article

Page created: December 10, 2014
Page updated: December 10, 2014
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