Mortality After Discharge From Acute Care Hospitalization With Traumatic Brain Injury: A Population-Based Study

Abstract 

Ventura T, Harrison-Felix C, Carlson N, DiGuiseppi C, Gabella B, Brown A, DeVivo M, Whiteneck G. Mortality after discharge from acute care hospitalization with traumatic brain injury: a population-based study.

Objective

To characterize mortality after acute hospitalization with traumatic brain injury (TBI) in a socioeconomically diverse population.

Design

Population-based retrospective cohort study.

Setting

Statewide TBI surveillance program.

Participants

Colorado residents with TBI discharged alive from acute hospitalization between 1998 and 2003 (N=18,998).

Interventions

Not applicable.

Main Outcome Measures

Vital status at the end of the study period (December 31, 2005) and statewide population mortality rates were used to calculate all-cause and cause-specific standardized mortality ratios (SMRs) and life expectancy compared with population mortality rates. The influence of demographics, injury severity, and comorbid conditions on time until death was investigated using age-stratified Cox proportional hazards modeling.

Results

Patients with TBI carried about 2.5 times the risk of death compared with the general population (SMR=2.47; 95% confidence interval [CI], 2.31–2.65). Life expectancy reduction averaged 6 years. SMRs were largest for deaths caused by mental/behavioral (SMR=3.84; 95% CI, 2.67–5.51) and neurologic conditions (SMR=2.79; 95% CI, 2.07–3.77) and were smaller but significantly higher than 1.0 for an array of other causes. Injury severity and older age increased mortality among young people (age <20y). However, risk factors for mortality among adults age 20 and older involved multiple domains of demographics (eg, metropolitan residence), injury-related measures (eg, falls versus vehicular incidents), and comorbidity (eg, ≥3 comorbid health conditions versus none).

Conclusions

TBI confers an increased risk of mortality in the months and years after hospital discharge. Although life expectancy is reduced across the population, the excess in mortality lessens as time since injury increases. Specific risk factors (eg, high injury severity, poor general health) pose an especially high threat to survival and should prompt an increased vigilance of health status, especially among younger patients.

Key Words: Brain injuries, Comorbidity, Mortality, Population surveillance, Rehabilitation

List of Abbreviations: AIS, Abbreviated Injury Scale, CDC, Centers for Disease Control and Prevention, CDPHE, Colorado Department of Public Health and Environment, CI, confidence interval, CTBISS, Colorado Traumatic Brain Injury Surveillance System, GCS, Glasgow Coma Scale, HR, hazard ratio, ICD-9, International Classification of Diseases–9th Revision, ICD-9-CM, International Classification of Diseases–9th Revision–Clinical Modifications, ICD-10, International Classification of Diseases–10th Revision, MSA, metropolitan statistical area, PH, proportional hazard, SMR, standardized mortality ratio, TBI, traumatic brain injury