Table 4.

Sample Size Estimates for Use of Supplemental Oxygen–Free Days as an End Point in Clinical Trials of Proven/Probable Respiratory Syncytial Virus Lower Respiratory Tract Infection in Hematopoietic Cell Transplant Recipients

End Point
Day 28 mortality rate, reduction from baseline,b %	Odds Ratio	Recipients/Arm, No.a
2.5	0.874	4677
5	0.757	1128
10	0.542	260
15	0.352	105
20	0.182	52
Oxygen-free days by day 28, increase from baseline,c no.	Effect Sized	Recipients/Arm, No.e
2	0.164	586
4	0.328	147
6	0.492	66
8	0.656	38
10	0.82	25

Estimates were made on the assumptions of a type 1 error of 5% and a power of 80%.

^aCalculated by a 2-sided Pearson χ² test.

^bThe baseline value was 26%.

^cThe baseline value was 15 days.

^dCalculated as the increase from baseline, divided by a SD of 12.2.

^eCalculated by a 2-sided test.