Contacts Storage process consumes more than 53% of battery life

I have a Nexus 5 running Android 5.0 Lollipop. The Battery Doctor app points to "Contacts Storage," which is a native Android process as the chief consumer of battery life. The Contacts Storage process consumes more than 53% of battery life. Can't disable the process because no other app can reach or display my contacts when "contacts storage" is disabled. Tried factory reset and things looked OK for the first two weeks. Now it's back to consuming battery life like crazy. Any app can replace this native, horrid process?