We prove that for a one-ended hyperbolic graph X, the size of the quotient X G by a group G acting freely and cocompactly bounds from below the number of simplices in an Eilenberg-MacLane space for G. We apply this theorem to show that one-ended hyperbolic cubulated groups (or more generally, one-ended hyperbolic groups with globally stable cylinders à la Rips-Sela) cannot contain isomorphic finite-index subgroups of different indices.