Should I be concerned, 3 hosts in a cluster showing datastores with however the backing storage has been removed. Whats the safest thing to do to clear this?

I have 3 hosts (version 5.0 build 1476327) that are showing the datastores present but the backing device has now gone.  Oddly others in the same cluster are fine, I'm mildly concerned about the host crashing due to a APD condition.  Unfortunately evacuating the hosts is probably not an option due to licensing, can anyone advise of the best/safest course of action.