TABLE 3 ] .

Sample Size Estimates for Selected Cohorts in a Two-Year Study

	Sample Size Estimate (90% Power)
Cohort/End Point	HR = 0.50	HR = 0.60	HR = 0.70	HR = 0.80
GAP stage 1
Death	4,548	7,454	13,938	33,024
Death or hospitalization	1,302	2,140	4,014	9,532
GAP stage 2
Death	1,820	2,988	5,596	13,280
Death or hospitalization	456	758	1,430	3,420
GAP stage 3
Death	456	758	1,430	3,420
Death or hospitalization	230	386	738	1,784
GAP stages 1 and 2
Death	2,602	4,268	7,986	18,936
Death or hospitalization	676	1,116	2,098	5,000
GAP stages 2 and 3
Death	730	1,204	2,264	5,390
Death or hospitalization	306	510	968	2,328
GAP stages 1, 2, and 3
Death	1,012	1,666	3,128	7,436
Death or hospitalization	410	680	1,286	3,076

To achieve 90% power with a two-sided type I error of 0.05, an HR of 0.50 would require 87 events; an HR of 0.60, 161 events; an HR of 0.70, 330 events; and an HR of 0.80, 844 events. Samples sizes reported are the total sample sizes required for a two-arm study using a 1:1 allocation ratio, assuming uniform enrollment over 1 y followed by a minimum of 1-y follow-up for the last patient enrolled. One-year death rates for the control group are assumed to be 2%, 5%, and 20% for GAP stages 1, 2, and 3, respectively. One-year death or hospitalization rates for the control group are assumed to be 7%, 20%, and 40% for GAP stages 1, 2, and 3, respectively. HR = hazard ratio. See Table 1 legend for expansion of other abbreviation.