The review conducted at University Hospital went back 15 years and turned up four deaths from dog attacks, all attributed to pit bulls, the San Antonio Express-News reported Sunday.
The review also concluded injuries from pit bulls tended to be more serious and cost more to treat than other dog bites.
The newspaper said the study, published in the April issue of Annals of Surgery, concluded the distinct differences were a reason pit bulls should be subject to stricter regulations.
Some dog owners and veterinarians took issue with the study, saying it was not scientific enough to justify legislation restricting ownership of the animals.
Britney Spears debuts 'Perfume' video
Wisconsin business offering 'therapeutic cuddling' forced to close