Well depends you've also gotta do something ridiculous like glue their hands to their nipples/genetals because otherwise they could simply cut the thread before their anus seals and well then they'd have a bloody anus but they'd beting and you'd be losing out on their death.
Personally if I was ever going to chain someone up I would do it with something where even the attempt to escape would result in extreme pain for example, piercing a guys ballsack and nipples and then chaining that to the wall, so long as the chain is strong the weak point will be their skin/body part can you see any guy voluntarily ripping his balls off to escape? Same with women and their clitoris...That in itself is torture, knowing that you can escape, the door isn't even locked but that to do so you've gotta inflict the most pain you could ever think of on yourself.