2.2. Sample Size
PMS
The sample size for the primary outcome was calculated based on the difference in mean DRSP scores for a two-group parallel clinical trial with equal allocation. The acceptable effect at which superiority could be declared if there was a decrease in the summary DRSP score of six on the DRSP tool in the intervention group compared to the control group was used. The true difference was considered to be seven, and the conservative estimate of an expected standard deviation in the population in the trial was considered to be 1.5, resulting in an effect at a size of 0.67. For a power of 80% and α of 5%, the required sample size in each group was 28 subjects. Anticipating a dropout of 25%, the expected sample size was 35 PMS subjects in each group. nMaster 2.0 software was used to calculate the sample size [