Sample Size Estimation
Based on previous studies on exercise in hypertension, we expected
the intervention to result in a decrease of daytime systolic 24-hour
ABP (primary end point) of 6 mm Hg in the training group with no
changes in the control group.
13–15
This difference was considered to
be clinically relevant. A sample size of 23 in each group has 80%
power to detect this difference assuming that the common SD is 7
mm Hg with a 2-sided P0.05. We estimated the dropout rate to be
5% to 10%, leading to an overall sample size of 50 patients.