Table 3

Sample size estimations
Outcome Minimum relevant difference Risk of type I error Risk of type II error Total number of participants needed
Total sick days 5 days (SD* 21 days) 1.67% 20% 742
DLQI 1.2 points (SD 4.8 points) 1.67% 20% 672
Subjective assessment of hand eczema severity 20% risk reduction from 60% event rate in the control group 1.67% 20%§ 720

*Standard deviation of the mean.

Dermatology Life Quality Index.

Will be reduced to 15.7% when 742 participants are included.

§Will be reduced to 18.6% when 742 participants are included.

Fisker et al.

Fisker et al. BMC Dermatology 2013 13:16   doi:10.1186/1471-5945-13-16

Open Data