Bitcoin is great for hiding funds and u can use mixers to retain anonymity so for now it does lead to corruption I think. In the future however if you pay someone in bitcoin you can demand and see proof of which addresses a business or politician sends funds to provided you know their original address.
Mixer use to split the bitcoin in multiple segment of pieces. This will shows anonymity of bitcoin transaction, but its nothing will do for the corruption. You need clearly understand that bitcoin is wil take out the corruption if it is been implemented as legal money then all would be under one ledger.
Right now too everything comes under one ledger, but you cannot track the end to end user who involved into the particular transaction. You could have transparency in the transaction and if the anonymity is lost its same as using our traditional fiat. Bitcoin doesn't lead to corruption, but the knowledge base of people make use of it for corruption as it gives ease of transaction and anonymity.