Dr. John M. Leventhal, professor of pediatrics and nursing at Yale University in New Haven, Conn., and director of the Child Abuse Programs at Yale-New Haven Children's Hospital, said the findings were in sharp contrast to data from child protective services agencies, which show a 55 percent decrease in physical abuse cases from 1997 to 2009.
Leventhal and study co-author Julie R. Gaither, a graduate student in the Yale School of Public Health, studied data from the Kids' Inpatient Database, a sample of discharges from U.S. hospitals from 1997 to 2009.
The data also provided information on demographics, health insurance, if the child died during hospitalization and the length of hospital stay.
The study, scheduled to be published in the journal Pediatrics in November, found the number of children hospitalized due to abuse-related injuries increased by 4.9 percent over the 12 years.
The study raises concerns that improved results from the U.S. child protective services agencies might be due to reporting changes rather than a true lessening in abuse.
One possible reason for the divergent results is that studies by child protective services agencies included all cases of physical abuse regardless of age or severity, while the Yale study focused only on serious physical abuse, Leventhal said.