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Why The Texas Study on Mortality, Mauling & Maiming by Vicious Dogs Is Scientifically Unreliable

Delise Critiques Methodolgy
of Study and Conclusions

In April 2011, The Annals Of Surgery published the Texas based study Mortality, Mauling and Maiming by Vicious Dogs. The study detailed severe and fatal injuries and credited pit bulls as the culprits responsible for the injuries. It claimed the study examined the medical records of patients admitted to the level I trauma center in San Antonio University Hospital with dog bite injuries over a 15-year period.


The Stated Objective of the Study: Maiming and death due to dog bites are uncommon but preventable tragedies. We postulated that patients admitted to a level 1 trauma center with dog bites would have severe injuries and that the gravest injuries would be those caused by pit bulls.

Delise: Pit Bull Bites Are Not Identifiable
From Other Big Breed Dogs

Yet, according to fatal-dog-bite expert Karen Delise, it is impossible to look at injuries resulting from a dog attack and determine what breed or type of dog was involved. In fact, Delise says “If you’ve seen enough autopsy photos like I have, if what they are saying is true, that pit bulls inflict injuries unlike any other dogs well then you should be able to look at a photograph of a person that received a severe dog bite and tell me what breed did it. But you can’t. I mean I’ve seen hundreds of hundreds of photos and you can’t tell the difference from one breed or type of dog to another. If a dog intends to inflict a severe bite it’s going to inflict a severe bite.”

So how did non-animal experts Bini (MD), Cohn (MD), Acosta (RN, BSN), McFarland (RN, MS), Muir (MD), and Michalek (PhD) conclude that pit bulls are more capable of inflicting the gravest injuries?

The Stated Design of the Study: We reviewed the medical records of patients admitted to our level 1 trauma center with dog bites during a 15-year period. We determined the demographic characteristics of patients, their outcomes, and the breed and characteristics of the dogs that caused the injuries.

Okay, they should all have plenty of experience with the review of medical records. But how did they determine ‘the breed and characteristics of the dogs that caused the injuries’ from reviewing medical records?

Canine Expert Voith Disagrees with Concept of Breed Visual Identification

According to Victoria Voith, PhD, DVM, DACVB who conducted a study of adoption agency (shelter) personnel [people that work with dogs of different breeds, types and mixes every day] had a success rate of less than 25% when visual ID was compared to DNA testing of the dogs included in the study.

Stated Results of the Study: Our Trauma and Emergency Surgery Services treated 228 patients with dog bites injuries; for 82 of those patients, the breed of dog involved was recorded (29 were injured by pit bulls). Compared with attacks by other breeds of dogs, attacks by pit bulls were associated with a higher median Injury Severity Scale score (4 vs. 1; P=0.002), a higher risk of an admission Glasgow Coma Scale score of 8 or lower (17.2% vs. 0%; P = 0.006), higher median hospital charges ($10,500 vs. $7200; P = 0.003), and a higher risk of death (10.3% vs 0%; P = 0.041).

So, if we can’t rely on animal shelter workers that see hundreds of dogs of various breeds and types on a regular basis to correctly identify a breed of dog 75% of the time, how do we rely on ‘medical records’ to correctly identify a breed or type of any dog involved in an attack?


Stated Study Conclusion: Attacks by pit bulls are associated with higher morbidity rates, higher hospital charges, and a higher risk of death than are attacks by other breeds of dogs. Strict regulation of pit bulls may substantially reduce the US mortality rates related to dog bites.

This is the conclusion Bini (et al) came too after reviewing 228 patient records over a 15 year period? This is the conclusion Bini (et al) came to without consulting a single expert from the animal profession?

Bite Expert Addresses

In a “Letter to the Editor” of the Annals Of Surgery published this month, Delise responds “On the basis of my experience with this issue, I am dismayed by the erroneous data,the use of questionable sources, and the lack of fact checking that characterizes Dr Bini’s article.3 On the basis ofmy experience with this issue, I am dismayed by the erroneous data, the use of questionable sources, and the lack of fact checking that characterizes Dr Bini’s article.

Now, readers should understand that writing a letter to the editor of the Annals of Surgery is unlike writing a letter to the editor of your local newspaper.  Not just ‘anything’ will be published in the journal.  It is considered by peers in the medical profession, and when it debates a peer reviewed study the study author is provided a period of time to review it and respond to allegations of discrepancies before the letter will be printed. 

Ms. Delise responded immediately to the Bini (et al) study.  The Journal provided ample time for Dr. Bini to respond but no response was ever received.  No rebuttal was provided. 

Therefore it appears that information used as a basis to determine any and all of Dr. Bini’s (et al) conclusion is less than reliable.  For instance, according to the response by Ms. Delise in her Letter to the Editor there are in fact several errors.

Case Presentation 

In the first line, Dr. Bini writes, “An 11-month-old boy arrived at our level 1 trauma center after being mauled by 2 pit bulls.”  Delise contends “There is no documented evidence from any authority that either dog involved in this incident were “pit bulls”.  To determine whether the breed attributed to these dogs could be visually substantiated by a recognized expert, I submitted photographs of both dogs to Dr. Amy Marder, VMD, CAAB.  Dr. Marder reported the breed(s) of dog could not be reasonably determined by visual identification.”

Massaging the Numbers

Dr. Bini (et al) cite the 1982 Pediatrics study “Traumatic deaths from dog attacks in the United States” (Pinckney and Kennedy), “Between 1966 and 1980…although 16 deaths were attributable to German Shepherd Dogs and only 6 were attributable to pit bulls, there were 74,723 registered German Shepherd Dogs and only 929 registered pit bulls.”

Pinckney based his ‘pit bull’ population number and the resulting rate or highest number of deaths on the total of 1976 AKC registrations of “Bull Terriers”.  Yet, a pit bull as defined by Bini is an “American Staffordshire Terrier, American Pit Bull Terrier, and a Staffordshire Bull Terrier.  How can the study compare apples and oranges and have any credibility?

Denver Influence

 Delise goes on to outline problems within the studies use of Tables, identifying that in Table 2 the authors describe Table 2 as “adapted from Reference 14”.  (Reference 14 is Nelson KA. One city’s experience: why pit bulls are more dangerous and breed-specific legislation is justified. Municipal Lawyer. 2005;46:6)  “It is an article in the periodical Municipal Lawyer that contains no tabular information of any kind or nature.” and the Media

Again, a questionable source is cited on page 795 of the Journal when Bini claims “Over a recent 3-year period from January 2006 to March 30, 2009, a total of 98 dog bite fatalities involving 179 dogs occurred…A total of 113 pit bulls were involved in these deaths, and they accounted for 63% of the dogs involved in fatal attacks (Table 2).”  Bini’s ‘source’?


Bini used this as a basis for including Table 2 when according to Delise’s Letter, queries of the CDC database and state vital statistics reveal that from January 2006 to March 20, 2009, there were 101 dog bite-related fatalities, involving at least 187 dogs – a total of 3 more dog bite fatalities and 8 more dogs than is reported at using the media accounts.  Delise’s findings, based on interviews with veterinarians, animal control, and police investigators revealed that most of these dogs were of unknown pedigree (even when the media was quick to report an incident as a specific breed of dog attack) outline the discrepancies. 

A Quick Wave of the Wand

Table 2, Column 3 of Dr. Bini’s study did not total the registered dogs as defined by the studies definition of pit bull.  The first breed listed is ‘pit bull, with a total of 2239 registrations for 2007.  The study has an author’s footnote that defines the ‘term pit bull refers to “American Pit Bull Terrier, American Staffordshire Terrier and Staffordshire Bull Terrier” but also notes that ‘data presented only for dog breeds for which registration information is available from the American Kennel Club (AKC).’ 

Delise explains that while authors use breed club registrations as a tool to analyze the US dog population (a practice that most animal experts disagree with), Dr Bini (et al) seems unaware that the American Pit Bull Terrier, the most popular of the 3 breeds Bini (et al) define as pit bull is not even recognized by the AKC. 

Since APBTs are registered only by the United Kennel Club and the American Dog Breeders Association, the total in column 3 of Table 2 would indeed be incomplete, or untallied, by not including the number of registrations by each of the clubs that would hold the registrations. 

Delise cited only a small few of the numerous errors in the source material used by Dr. Bini concerning dog bite-related fatalities but offered additional case examples upon request.  

So, was this just a case of a sloppy study?  I would like to hope that medical professionals conducting studies that impact the lives of thousands (both human and animal alike) would ensure their expertise as well as the reliability of their sources. 

Biased Sources 

Not only did Bini’s sources share erroneous statistics, but also chooses their material on a very selective, if not deceitful, manner.  For instance, Delise points out:

1. Cause of deathwas not a result of dog bites:

On February 9, 2007, James Chapple was attacked by 2 dogs identified by the media as “pit bulls.” Mr Chapple received severe injuries but fully recovered and was discharged from the hospital. On May 17, 2007, Chapple was found dead in his bed. The Shelby County Medical Examiner (Case nos. 2007–1177) listed the cause of death as hypertensive and atherosclerotic cardiovascular disease. Dog bites were neither the cause nor a contributing factor in the death of Mr Chapple.

2. Unresolvable disagreement as to breed descriptor: On October 5, 2008, a 2-month-old boy was killed by a dog. One media source reported the dog to be a “pit bull” on the basis that “neighbors believe the dog to be a pit bull.” Other news stories quoted the Hawaiian Humane Society, which had custody of the dog, which officially reported that the dog “was not a pit bull.” Honolulu Police Investigators list the dog as a “Sharpei mix” on their incident report. (Voith)

Blatant bias in selecting the sources for her own ‘research’, as Pit Bulletin Legal News reported last month is normal procedure in the pro-bsl world.

The conclusion of this study should most likely read:There are a number of things that you can do to avoid dog bites, ranging from properly training and socializing your pet to educating your children on how, or if, they should approach a dog. Information is one of the best cures for this public health crisis.

The study will undoubtedly be cited by those in favor of Breed Specific Legislation as proof of the danger of Pit Bulls. Never mind there is no such breed. It is therefore imperative to understand how the study was done and its flawed methodolgy in order to bring objectivity to the discussion.

Selma 19.04.2012 (20:08:34)  
Mauling Study from Texas No0  

I'm sick of this BS. The major problem with the study is right in the objectives:

The Stated Objective of the Study: Maiming and death due to dog bites are uncommon but preventable tragedies. We postulated that patients admitted to a level 1 trauma center with dog bites would have severe injuries and that the gravest injuries would be those caused by pit bulls.


This is not a scientific question, it's a postulated conclusion which they then tried to prove. Odd method indeed.


In the Netherlands, where they did a report on their 15-yr-old ban before scrapping it, they actually found the opposite. This is a clip from a radio spot I did re: comparative severity of bites by 'pit bull terriers' vs other types:

They then compared bites by 'pit bull terriers' to those of other dogs to see if there was a difference in severity. They explain how they derive all of their data but it is complicated and likely too boring to go into here. This study was very thorough, the report is 92 pages long. The conclusion about severity was as follows, and I quote:

There appears to be no significant correlation between the breed type of the dog bite (whether or not the dog was of the type pit bull terrier) and the severity of the injury: 20 of the 64 bites caused by a pit bull terrier type were serious (31%), compared with 51 of the 145 bites (35%) which caused severe wounds made by dogs other than dogs of the type pit bull terrier (P = 0091 N = 209).

Regarding fatalities, this was the finding:

When they looked at dog bite data from 1982 to 2006, specifically dog bite related fatalities, they found that on average there were zero to two per year. I quote from the translated report:

"This is a small fraction of the total number of deaths with a non-natural cause (in 2006 it was 0.04%). The number of deaths caused by a bite from a dog is almost equal to the number of people killed by a lightning strike."

Karen Delise 20.04.2012 (02:55:49)  
Bini \"Study\" No0  

Thank you for PBLB for covering this.

When I first submitted my Letter to Editor at the Annals of Surgery they would not publish it because it was too long.

I actually had four type written pages of errors found in Bini's study. I was happy they eventually published my letter, but dismayed that I had to shorten it to such a degree that many other errors were left unaddressed.

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