I would think DM neurogenic bladder almost invariably results in overflow incontinence (i.e., lack of detrusor function), since this is LMN. You wouldn't get hyperfunction unless the denervation were UMN, but that's not really a diabetic aetiology - more MS. Any DM patient I've seen in clinic with bladder issues, it's always overflow. No, you would not use anticholinergics in these patients and would be sitting in front of a judge if you did.