I think it is a common and understandable mistake to assert that Patrick Bateman does not "actually" kill in the book, and to cite as evidence for this the fact that no one is reported missing after their deaths, and that people Patrick has supposedly killed are spotted at parties, etc.
In fact, this evidence is misleading. To take American Psycho as part of a major arc of fiction by Ellis, we see that in ALL of his books there are cases of identity-confusion, or in fact the total loss of individual identity altogether.
Even within American Psycho itself, Bateman is often mistaken for other people, and other people mistaken for Bateman or for other other people! This is simply because Ellis is satirising the fact that all 20-something Wall Street wannabe Yuppies in the 80s looked and sounded the same - they all aspired to the Gordon Gecko look (itself an image that started as satire and achieved aspirational iconic status much to its creator, Oliver Stone's, horror).
So when people tell Patrick they have seen his "victims" alive and well at restaurants after their supposed deaths, the suggestion is that they are truly dead, but will never be missed because they were never identifiable or memorable individually anyway. It is a soulless universe where lives are as interchangable as ties or handbags.
As I said, this continues a major theme in Brett Easton Ellis' other novels Less Than Zero and Rules of Attraction, where again people often claim to have seen characters in places we know they have no been because of this identity confusion (in these cases the blond, tanned, slim, muscular, vacant Californian pretty boys are the "clones").
This theme continues through Glamorama and into the wonderful short story collection The Informers, to the point where a father does not even recognise whether a figure through a window is his son, his son's boyfriend, or any one of a million such "boys".
Better evidence for Bateman's violence being as imaginary as his success is the mythical/movie-like escape from imminent police capture. This echoes Bateman's addiction to cheap action movies and cable TV shows, and shows his narcissism and self-aggrandisement in equal measure.
This is a great book, one of the true greats. That is why it is loved and hated so ferociously. And as a reviewer says above, if a book is so dark it forces you to feel repulsed or even look away, it has achieved a state very little art still can in our desensitised times. Power like that is very hard to achieve in print.