. Author manuscript; available in PMC: 2015 Sep 1.

Published in final edited form as: Aliment Pharmacol Ther. 2014 Jul 13;40(5):477–485. doi: 10.1111/apt.12862

Table 7.

Number of UC Patients and Number of Rectal Biopsies Required to Detect Differences in Gene Expression Corresponding to Active versus Inactive Disease

	Number of Patients

Number of Biopsies	IL-1β	IL-6	IL-8	TNFα	IP-10	CXCL-13	MMP3	S100A8
3	2	2	2	2	2	6	2	2
6	2	2	2	2	2	4	2	2
9	2	2	2	2	2	2	2	2

Using a linear mixed effect model with repeated measures, the power to detect changes in inflammatory gene expression in rectal biopsies corresponding to active versus inactive UC was calculated. With a fixed number of biopsies before and after treatment, the minimum number of UC patients needed to obtain a power of 80% is reported.