Table 4.

Sample size calculation and assumption of postoperative complications for each surgical procedure

Surgical procedure	All procedures	Pouch surgery	APR	TC
Patients with CDC complications, n (%)	321/588 (54.59)	214/425 (50.35)	48/72 (66.67)	59/91 (64.84)
XX % reduction in complications	40	40	40	40
Mean CCI±SD	15.23±18.35	13.16±14.53	14.63±18.54	25.38±28.37
Δ	10	10	10	10
Sample size/group (CDC)	80	92	54	58
Sample size/group (CCI)	54	35	55	128

CDC, Clavien-Dindo classification; CCI, comprehensive Complication index; APR, abdominal perineal resection; TC, total colectomy.

CDC: calculated sample size to achieve 80% power by the χ² test.

CCI: calculated sample size to achieve 80% power by the t test.