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Table 2 Sample size justification

From: Inhibiting the progression of arterial calcification with vitamin K in HemoDialysis patients (iPACK-HD) trial: rationale and study design for a randomized trial of vitamin K in patients with end stage kidney disease

Control arm CAC progression rate

Relative risk reduction

Phylloquinone arm progression rate

Sample size per arm for 80% power

80

20%

64%

123

70

20%

56%

186

60

20%

48%

270

50

20%

40%

388

80

25%

60%

80

70

25%

53%

121

60

25%

45%

173

50

25%

38%

247

RRR = Relative risk reduction

  
  1. Estimate of the power for testing the effect of the intervention. The effect sizes are described in terms of relative risk reduction for a > 15% increase in CAC score over baseline in 12 months. The bolded row indicates estimates utilized for sample size calculation for the iPACK-HD trial.