The bushes will have lost their leaves because they could not take up water from the frozen ground, but they may not be dead. If you can bear to see the leafless branches for another month or two I would leave them and see what happens.

i agree i have a ceanothus and they shed their leaves readily in times of stress, leaves them for a bit and then prune them back a bit if there are any bare branches.

All suspected deaths should be left until at least June, especially after the winter that we have had!