TY - JOUR
T1 - Sample size calculation for comparing time-averaged responses in k-group repeated-measurement studies
AU - Zhang, Song
AU - Ahn, Chul
N1 - Funding Information:
This work was supported in part by NIH grants UL1TR0000451 and P30CA142543 , and CPRIT grants RP110562-C1 and RP120670-C1 .
PY - 2013/2
Y1 - 2013/2
N2 - Many clinical trials compare the efficacy of K (<3) treatments in repeated measurement studies. However, the design of such trials has received relatively less attention from researchers. Zhang and Ahn (2012) derived a closed-form sample size formula for two-sample comparisons of time-averaged responses using the generalized estimating equation (GEE) approach, which takes into account different correlation structures and missing data patterns. In this paper, we extend the sample size formula to scenarios where K (<3) treatments are compared simultaneously to detect time-averaged differences in treatment effect. A closed-form sample size formula based on the noncentral χ 2 test statistic is derived. We conduct simulation studies to assess the performance of the proposed sample size formula under various correlation structures from a damped exponential family, random and monotone missing patterns, and different observation probabilities. Simulation studies show that empirical powers and type I errors are close to their nominal levels. The proposed sample size formula is illustrated using a real clinical trial example.
AB - Many clinical trials compare the efficacy of K (<3) treatments in repeated measurement studies. However, the design of such trials has received relatively less attention from researchers. Zhang and Ahn (2012) derived a closed-form sample size formula for two-sample comparisons of time-averaged responses using the generalized estimating equation (GEE) approach, which takes into account different correlation structures and missing data patterns. In this paper, we extend the sample size formula to scenarios where K (<3) treatments are compared simultaneously to detect time-averaged differences in treatment effect. A closed-form sample size formula based on the noncentral χ 2 test statistic is derived. We conduct simulation studies to assess the performance of the proposed sample size formula under various correlation structures from a damped exponential family, random and monotone missing patterns, and different observation probabilities. Simulation studies show that empirical powers and type I errors are close to their nominal levels. The proposed sample size formula is illustrated using a real clinical trial example.
KW - Generalized estimating equation (GEE)
KW - Longitudinal outcome
KW - Sample size
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U2 - 10.1016/j.csda.2012.08.013
DO - 10.1016/j.csda.2012.08.013
M3 - Article
C2 - 23183937
AN - SCOPUS:84869086497
SN - 0167-9473
VL - 58
SP - 283
EP - 291
JO - Computational Statistics and Data Analysis
JF - Computational Statistics and Data Analysis
IS - 1
ER -