First, if there is another wizard, they can cancel your Levicorpus. Like Tonks saved Harry on the Hogwarts Express when Malfoy cursed Harry with full body-bind curse.
Second, I think those binding spells have a time limit. In the first book, Hermione casts 'Petrificus Totalus', which is a Full Body-Bind Curse to Neville and then leaves the room to find the stone and comes one day later. But Neville is fine. (It is also possible that someone from the common room lifted it, so first case.)
Third, this person is only affected by the spell as long as you live. When Dumbledore dies, Harry is freed from his body binding spell. So you can not leave them there forever.
Lastly and the best answer to your question, I think non-wand magic casters (like Voldemort and Dumbledore) can free themselves from the spell, even disarmed.
I know this is not all about Levicorpus but as Valorum stated out, in your example the killing factor is leaving someone in a room without food or water and making them immobile. This can all be done in the muggle world without much effort.(Don't try this at home!!)
Edit: After watching Fantastic Beasts movie, I have remembered another method to get away from this Spell. You can easily Apparate to a safe location and even though you are still under the spell, you can let someone cancel the spell. Of course this does not work in Hogwarts.