Table 1

Sample size calculations for the primary trial outcomes

OutcomeValue in standard dose (20 mg/day) groupExpected value in low-dose groupsNon-inferiority marginPower, significance levelSample size per arm
(with ~5% attrition)
Duration of diarrhoea, mean (SD)3.0 (2.7) days3.0 (2.7) days
Lower dose equally effective
0.3 days90%, 5%1460
Percentage of children with diarrhoea >5 days16%16%
Lower dose equally effective
+4%90%, 5%1500
Total number of loose or watery stools during follow-up, mean (SD)10 (9) stools10 (9) stools
Lower dose equally effective
+2 stools90%, 5%1460
Percentage of children with vomiting during follow-up20%15%
Lower dose safer
Not applicable because of superiority hypothesis for this outcome90%, 5%1340