Considering the Communists only had 20% support and United Russia appears to be walking away with 50%, that leaves 30% of the vote up in the air. I doubt the loss of support for United Russia flipped to the Communists, so they might have gone to other parties.
The Communists received 12% of the vote in 2007 and 20% in 2011. That’s quite an accomplishment and Gennady Zyuganov has studied the record of the only Communist Party to win a free election in the post-Soviet space, the Party Of Communists of Moldavia, now in opposition in that country. Its the only Russian political party with anything like a nationwide organization.
Two pro-Kremlin satellite parties gained seats so UR should be able to get its agenda easily passed with their support. Putin’s advantage is there is no real challenger in sight who can threaten his presidential run. If the economy sours, then of course it could all change quickly by then.