We don't know since there is no way as of now to scientifically compare those firmwares.
No device that has Denim now has had Cyan. (830, 730, 535 launched with Denim firmware)
No current Cyan (and earlier) device has Denim (Unless I'm horribly mistaken)
So there's no way to really compare the two directly yet.
Although I'm going to wager no. Don't see why it would. It's possible, but I doubt it.
Even if there was drain, we probably won't know 100% if it was due to Denim or something else.