Sample size calculation
It was assumed that 24% of the patients would be on β-blockers and/or
ACEI. A χ2 test with a two-sided 5% significance level has an 80%
power to detect the difference between the group without
antihypertensive medication with 6% systemic AE during VIT and the
group on β-blockers and/or ACEI with 12.3% systemic AE during VIT (OR =
2.2) when the sample sizes are 631 and 200 (a total sample size of 831),
respectively. The drop-out rate included study drop-outs (30%) who did
not start VIT and study drop-outs (10%) who did not finish VIT. This
resulted in a drop-out rate of 37% and a required number of 1,319
patients.