2.3. Sample Size Calculation and Statistical Power
MINOR
For our randomized, placebo-controlled trial, the primary objective was to discern a 15% reduction in LDL-C levels in the omega-3 fatty acid group compared to the placebo group, with an anticipated average LDL-C level of 145 mg/dL. We considered a standard deviation of 15% in LDL-C level changes across both groups. The sample size calculation, incorporating a two-sided significance level of 5% and aiming for a power of 90%, was adjusted to account for the frequency of PPARG polymorphism. We initially estimated, based on the Hardy–Weinberg equilibrium and the minor allele frequency of PPARG, that 48 participants per group would be sufficient. To account for the PPARG polymorphism distribution in our target population and a potential dropout rate of 5%, we further adjusted the number. Consequently, we determined that enrolling 51 participants per group, inclusive of both polymorphic and non-polymorphic patients, would maintain the study’s statistical power. This adjustment brought the total sample size for the trial to 102 participants.