Sending hidden form field to server on a Wordpress site

I am new to working with Wordpress and I'm using a JQuery plugin called textcomplete with Algolia search to allow users to @ mention other users in the comment section of my site as shown in the code below.

    $input.textcomplete([
    {
        match: /\B@(\w*)$/,
        search: function(term, callback) {
            lastQuery = term;

            myIndex.search(term, { hitsPerPage: 5 }, function(err, content) {
                if (err) {
                    throw err;
                }

                if (content.query === lastQuery) {
                    callback(content.hits);
                }
            });

        },
        template: function (hit) {
            console.log(hit);
            return hit._highlightResult.display_name.value;
        },
        replace: function (hit) {
            return ' @' + hit.display_name + ' ';
        },
        index: 1
    }
]);

I want to send my hit.display_name variable to the server to use as part of a MySQL query. Normally I would do this by making it a hidden form field and posting it to the php file where it is required (in this case wp-comments-post.php) but with the way comment forms are handled with Wordpress (using a comment_form function and passing it an associative array of objects) I am not sure how to do this... So my question is how do I access this hit.display_name variable in my wp-comments-post.php file?