There were no significant differences between the colchicine and placebo groups for the secondary end points of postoperative AF ( colchicine , @ patients -LSB- @ % -RSB- ; placebo , @ patients -LSB- @ % -RSB- ; absolute difference , @ % ; @ % CI , -@ % to @ % ) or postoperative pericardial/pleural effusion ( colchicine , @ patients -LSB- @ % -RSB- ; placebo , @ patients -LSB- @ % -RSB- ; absolute difference , @ % ; @ % CI , -@ % to @ % ) , although there was a reduction in postoperative AF in the prespecified on-treatment analysis ( placebo , @/@ patients -LSB- @ % -RSB- ; colchicine , @/@ patients -LSB- @ % -RSB- ; absolute difference , @ % ; @ % CI , @ % -@ % ) .