Table 2.

Power for effects of a single agent on CVD in VITAL, a 2×2 factorial trial of 10,000 men aged ≥50 and 10,000 women aged ≥55, with 5 years of follow-up

Observed RRa	True RRb	Major CVDc	Total CVDd	CVD Mortality	MI	Stroke
0.90	0.875	34.6	52.8	-	-	-
0.85	0.812	66.1	86.9	-	-	-
0.80	0.750	89.4	98.6	45.1	50.9	51.0
0.75	0.687	98.2	>99.9	64.4	71.0	71.1
0.70	0.625	99.9	>99.9	80.9	86.4	86.5
0.65	0.560	>99.9	>99.9	91.9	95.2	95.2
0.60	0.500	>99.9	>99.9	97.3	98.8	98.8

^aObserved RR=intent-to-treat RR, including noncompliant participants. Compliance is assumed to be 80%.

^bTrue RR=that with perfect compliance.

^cMajor CVD=myocardial infarction, stroke, and CVD mortality

^dTotal CVD=myocardial infarction, stroke, CVD mortality, and coronary revascularization (coronary artery bypass grafting or percutaneous coronary intervention)

CVD, cardiovascular disease; MI, myocardial infarction; RR, rate ratio.