Representativeness of the Traumatic Brain Injury Model Systems National Database.

OBJECTIVE: To determine whether the Traumatic Brain Injury Model Systems National Database (TBIMS-NDB) is representative of individuals aged 16 years and older admitted for acute, inpatient rehabilitation in the United States with a primary diagnosis of traumatic brain injury (TBI).
DESIGN: Secondary analysis of existing data sets.
SETTING: Acute inpatient rehabilitation facilities. PARTICIPANTS: Patients aged 16 years and older with a primary rehabilitation diagnosis of TBI. MAIN OUTCOME MEASURES: Demographic characteristics, functional status, and hospital length of stay.
RESULTS: Patients included in the TBIMS-NDB from October 2001 through December 2007 were largely representative of all individuals 16 years and older admitted for rehabilitation in the United States with a primary diagnosis of TBI. The major difference in distribution was age-the TBIMS-NDB cohort did not include as large a proportion of patients older than 65 years as were admitted for rehabilitation with a primary diagnosis of TBI in the United States. Distributional differences for age-related characteristics were observed; however, groups of patients partitioned at aged 65 years differed minimally, especially within the younger than 65 years subset. Regardless of age, the proportion of patients with a rehabilitation stay of 1 to 9 days was larger nationwide. Nationwide admissions showed an age distribution similar to patients discharged alive from acute care with moderate, severe or penetrating TBI. The proportion of patients aged 70 years and older admitted for TBI rehabilitation in the United States increased every year, a trend that was not evident in the general population, TBIMS-NDB or among TBI patients in acute care.
CONCLUSIONS: These results provide substantial empirical evidence that the TBIMS-NDB is representative of patients receiving inpatient rehabilitation for TBI in the United States. Researchers utilizing the TBIMS-NDB may want to adjust statistically for the lower percentage of patients older than 65 years or those with stays less than 10 days.