Factors affecting hospital length of stay and charges following traumatic brain injury

Objective: To examine the effect of initial severity of traumatic brain injury (TBI), level of functional independence at admission to rehabilitation, medical complications, mechanism of injury, and payer source on hospital length of stay (LOS) and charges. Design: Cohort analysis. Setting: Inpatient rehabilitation. Patients: 525 subjects from the National Institute on Disability and Rehabilitation Research TBI Model Systems National Data Base with relatively mild to severe TBI, an average Glasgow Coma Scale (GCS) score of 8.5 (SD=3.9), and average duration of impaired consciousness (DIC) of 15.1 days (SD=40.6). Intervention: Inpatient rehabilitation. Main Outcome Measures: Hospital LOS, hospital charges. Results: Persons with lower initial GCS scores generally reached the rehabilitation setting later and stayed longer than persons with higher initial GCS scores. Within each GCS level, lower initial Functional independence Measure (FIM) scores were associated with longer acute care and rehabilitation LOS. For persons admitted to rehabilitation with relatively high or medium FIM scores, greater severity of injury resulted in relatively modest increases in rehabilitation LOS. In contrast, low admission FIM scores were associated with much longer rehabilitation LOS for patients with severe injuries, compared with those with relatively mild injuries. Initial GCS score, DIC, admission FIM, and acute LOS accounted for 48% (adjusted R(2)) of the variance in rehabilitation LOS and 42% of the variance in rehabilitation hospital charges. Of the medical complications examined, only neurologic complications and intracranial operations added significantly to the model, explaining an additional 2% of the variance In rehabilitation LOS. The effect of payer source on LOS is complicated by age as well as by severity and mechanism of injury. Conclusions: Age, severity of injury, and medical complications are powerful predictors of rehabilitation LOS and hospital charges. Other factors, such as functional independence at rehabilitation admission and length of acute hospitalization, explain additional variance. None of these factors in isolation is able to sufficiently predict rehabilitation LOS or charges. Multidimensional analysis of these factors is necessary to plan or administer the delivery of brain injury services.