Many people consider their dogs as best friends, but hospital records suggest some pooches feel otherwise.

Each year, approximately 4.5 million people in the United States are bitten by dogs, with some bites needing emergency treatment. Over a 16-year period, in fact, the number of hospital admissions caused by dog bites nearly doubled, increasing from 5,100 in 1993 to 9,500 in 2008, according to a recent report by the U.S. Agency for Healthcare Research and Quality.