Sample size
The trial was designed to recruit a total of 495 dyads (165 per arm) to detect a difference of 3 points in NPI-Q total severity score between the MI plus SC and SC alone at 90 days post-randomisation. This assumes 90% power, a two-tailed significance level of 5%, an equal standard deviation of 7.5 points in the groups, no correlation between baseline and 12 weeks (conservative) and 20% attrition. A 3-point change from baseline in NPI-Q total severity score is considered a clinically meaningful difference [