Method: Data from 1998-2014 from the National Inpatient Sample (NIS) was used for this retrospective study. ICD-9-CM diagnosis and external cause of injury codes were used to identify hospital admissions in which a child 3 years or younger had experienced physical abuse. Physical abuse was partitioned into three categories: 1) abuse not involving SBS (No SBS), 2) abuse involving confirmed SBS (Confirmed SBS), and 3) possible SBS. Cases were identified as possible SBS when there was no ICD-9-CM SBS diagnosis despite the presence of a type 1 traumatic brain injury (TBI) and either retinal hemorrhage or OT convulsions. Time trends for the probability of the three types of abuse were estimated using Generalized Estimating Equations (GEE) based on the multinomial distribution with the generalized logit link function. All analyses were done in SAS 9.4. NIS sampling weights were incorporated into all analyses to provide nationally representative estimates.
Results: Analysis included 71,854 children under three admitted to the hospital for physical abuse. Confirmed SBS accounted for 14% of admissions, possible SBS 6%, and no SBS 80%. A majority of admissions were male (54%) and white (48%). Blacks accounted for 22% of admissions, Hispanics 16%, and Asian or Pacific Islander, Native American, and Other 14%. A quadratic trend in time was found to be a better fit than a linear trend based on QIC (85,454 vs. 85,611). The trends for the probability of the three admission codes were all found to be statistically significant. The trend in the probability of no SBS physical abuse increased from 0.79 to 0.85 (p < 0.05) from 1998 through 2014, while the trend in confirmed SBS abuse decreased from 0.18 to 0.05 (p < 0.05). The trend in possible SBS also increased from 0.03 to 0.09 (p < 0.05).
Conclusion: Although many hospitals have introduced child abuse and maltreatment prevention programs, our analysis indicates that rates of SBS among children hospitalized for child maltreatment remained stable between 1998 and 2014. Several intervention strategies could reduce the number of hospitalizations and cost for taxpayers, including improved measures or assessment methods for diagnosing SBS and effective primary prevention programs.