The technical difference is lack of language-level module support, requiring manual management of vtables. It can be done, see Linux kernel for an example, but often times degenerates in a ball of globals.

To further clarify, one can use DOP style in many languages, including languages that are ostensibly OO. DOP is a style, using data hiding and polymorphism as sparingly as possible, as opposed to OOP style, which strongly encourages using data hiding and polymorphism at every corner.