Traumatic brain injury as a chronic disease: insights from the United States Traumatic Brain Injury Model Systems Research Program.

Traumatic brain injury (TBI) is a global health priority, associated with substantial burden. Historically conceptualised as an injury event with finite recovery, TBI is now recognised as a chronic condition that can affect multiple domains of health and function, some of which might deteriorate over time. Many people who have had a TBI remain moderately to severely disabled at 5 years, are rehospitalised up to 10 years post-injury, and have a reduced lifespan relative to the general population. Understanding TBI as a chronic disease process can be highly informative for optimising care, which has traditionally focused on acute care. Chronic brain injury care models must be informed by a holistic understanding of long-term outcomes and the factors that can affect how care needs evolve over time. The United States Traumatic Brain Injury Model Systems of Care follows up individuals with moderate-to-severe TBI for over 30 years, allowing characterisation of the chronic (2-30 years or more post injury) functional, cognitive, behavioural, and social sequelae experienced by individuals who have had a moderate-to-severe TBI and the implications for their health and quality of life. Older age, social determinants of health, and lower acute functional status are associated with post-recovery deterioration, while younger age and greater functional independence are associated with risky health behaviours, including substance misuse and re-injury. Systematically collected data on long-term outcomes across multiple domains of health and function are needed worldwide to inform the development of models for chronic disease management, including the proactive surveillance of commonly experienced health and functional challenges.

Life Expectancy of 1-Year Survivors of Traumatic Brain Injury, 1988-2019: Updated Results From the TBI Model Systems.

OBJECTIVE: To update the life expectancy estimates according to age, sex, mobility, and feeding skills reported in the 2015 study of Brooks et al. To examine trends in survival over the past decade. DESIGN: Observational cohort study. SETTING: Poisson regression and life table analysis applied to long-term follow-up data on United States (US) Traumatic Brain Injury (TBI) Model Systems patients recorded in the national database. Functional mobility and feeding skills were assessed with FIM. PARTICIPANTS: A total of 14,803 persons with TBI during the years 1988-2019 who underwent inpatient rehabilitation and provided at least 1 long-term assessment of functional skills 1 year or more postinjury (N=14,803). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Survival, mortality rates, and life expectancy. RESULTS: Life expectancy was lower than that of the age- and sex-matched general population. Older age and severity of functional impairments were risk factors for mortality (both P<.0001 in regression models). Among ambulatory individuals, mortality was 51% (95% confidence interval, 35%-69%) higher in men than women. Life expectancy of 20-year-old women who walked well (FIM ambulation score 7) was 55 (SE=0.8) additional years to age 75, representing a reduction of 6.9 years from the normal general population figure. For 20-year-old men who walked well, the life expectancy was 49 (SE=0.5) additional years, representing a reduction of 8.1 years from normal. Life expectancies for men and women who did not walk and were fed by others were much lower. There was no significant change in mortality rates during the study period (hazard ratio, 1.008; P=.07). CONCLUSIONS: There has been no significant change in the long-term survival of persons with TBI in the US since the late 1980s. The life expectancies reported here are similar to those reported in the 2015 study of Brooks et al, although they are more precise because of the larger sample size and longer follow-up.

Long-term survival after traumatic brain injury part I: external validity of prognostic models.

OBJECTIVES: To develop prognostic models for long-term survival in adults with traumatic brain injury (TBI) and to assess their external validity in 2 independent populations. DESIGN: Survival analysis. SETTING: Post-discharge from rehabilitation units and long-term follow-up at regional centers. PARTICIPANTS: Two cohorts of long-term survivors of TBI (N=12,481): the Traumatic Brain Injury Model Systems (TBIMS) cohort comprised 7365 persons who were admitted to a TBIMS facility and were assessed at ≥1 years postinjury, and the California Department of Developmental Services (CDDS) cohort comprised 5116 persons who sustained a TBI and received long-term services from the CDDS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Survival/mortality. RESULTS: Older age, male sex, and severity of disability in walking and feeding were significant predictors of increased long-term mortality rates (all P<.05, both databases). The CDDS model predicted 623 deaths for persons in the TBIMS cohort, with an observed-to-expected ratio of .94 (95% confidence interval [CI], 0.87-1.02). The TBIMS model predicted a total of 525 deaths for persons in the CDDS cohort, with an observed-to-expected ratio of 1.08 (95% CI, 0.99-1.17). Regression calibration statistics were satisfactory, and both models ranked survival times well from shortest to longest (TBIMS: C index, .78; 95% CI, .76-.80; CDDS: C index, .80; 95% CI, .78-.82). CONCLUSIONS: Long-term survival prognosis in TBI is related to age, sex, and severity of disability. When compared on the basis of these factors, the survival estimates derived from the TBIMS and CDDS cohorts are found to be similar. The close agreement between model predictions and actual mortality rates confirm the external validity of the prognostic models presented herein.

Long-Term Survival After Traumatic Brain Injury Part II: Life Expectancy.

OBJECTIVES: To compute the life expectancy of persons with traumatic brain injury (TBI) based on validated prognostic models from 2 cohorts, to compare mortality and life expectancy of persons with TBI with those of the U.S. general population, and to investigate trends toward improved survival over the last 2 decades. DESIGN: Survival analysis. SETTING: Postdischarge from rehabilitation units and long-term follow-up at regional centers. PARTICIPANTS: Two cohorts of long-term survivors of TBI (N=12,481): the Traumatic Brain Injury Model Systems (TBIMS) cohort comprised 7365 persons who were admitted to a TBIMS facility with moderate to severe TBI and were assessed at ≥1 years postinjury, and the California Department of Developmental Services (CDDS) cohort comprised 5116 persons who sustained a TBI and received long-term services from the CDDS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Life expectancy. RESULTS: The estimates of age-, sex-, and disability-specific life expectancy of persons with TBI derived from the CDDS and TBIMS were similar. The estimates of age- and sex-specific life expectancy were lower than those of the U.S. general population. Mortality rates of persons with TBI were higher than those of the U.S. general population. Mortality rates did not improve and the standardized mortality ratio increased over the study period from 1988 to 2010. CONCLUSIONS: Life expectancy of persons with TBI is lower than that of the general population and depends on age, sex, and severity of disability. When compared, the survival outcomes in the TBIMS and CDDS cohorts are remarkably similar. Because there have been no marked trends in the last 20 years, the life expectancies presented in this article may remain valid in the future.

Long-term disability and survival in traumatic brain injury: results from the National Institute on Disability and Rehabilitation Research Model Systems.

OBJECTIVES: To document long-term survival in 1-year survivors of traumatic brain injury (TBI); to compare the use of the Disability Rating Scale (DRS) and FIM as factors in the estimation of survival probabilities; and to investigate the effect of time since injury and secular trends in mortality. DESIGN: Cohort study of 1-year survivors of TBI followed up to 20 years postinjury. Statistical methods include standardized mortality ratio, Kaplan-Meier survival curve, proportional hazards regression, and person-year logistic regression. SETTING: Postdischarge from rehabilitation units. PARTICIPANTS: Population-based sample of persons (N=7228) who were admitted to a TBI Model Systems facility and survived at least 1 year postinjury. These persons contributed 32,505 person-years, with 537 deaths, over the 1989 to 2011 study period. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Survival. RESULTS: Survival was poorer than that of the general population (standardized mortality ratio=2.1; 95% confidence interval, 1.9-2.3). Age, sex, and functional disability were significant risk factors for mortality (P<.001). FIM- and DRS-based proportional hazards survival models had comparable predictive performance (C index: .80 vs .80; Akaike information criterion: 11,005 vs 11,015). Time since injury and current calendar year were not significant predictors of long-term survival (both P>.05). CONCLUSIONS: Long-term survival prognosis in TBI depends on age, sex, and disability. FIM and DRS are useful prognostic measures with comparable statistical performance. Age- and disability-specific mortality rates in TBI have not declined over the last 20 years. A survival prognosis calculator is available online (http://www.LifeExpectancy.org/tbims.shtml).

Standardizing data collection in traumatic brain injury.

Collaboration among investigators, centers, countries, and disciplines is essential to advancing the care for traumatic brain injury (TBI). It is thus important that we "speak the same language." Great variability, however, exists in data collection and coding of variables in TBI studies, confounding comparisons between and analysis across different studies. Randomized controlled trials can never address the many uncertainties concerning treatment approaches in TBI. Pooling data from different clinical studies and high-quality observational studies combined with comparative effectiveness research may provide excellent alternatives in a cost-efficient way. Standardization of data collection and coding is essential to this end. Common data elements (CDEs) are presented for demographics and clinical variables applicable across the broad spectrum of TBI. Most recommendations represent a consensus derived from clinical practice. Some recommendations concern novel approaches, for example assessment of the intensity of therapy in severely injured patients. Up to three levels of detail for coding data elements were developed: basic, intermediate, and advanced, with the greatest level of detail attained in the advanced version. More detailed codings can be collapsed into the basic version. Templates were produced to summarize coding formats, explanation of choices, and recommendations for procedures. Endorsement of the recommendations has been obtained from many authoritative organizations. The development of CDEs for TBI should be viewed as a continuing process; as more experience is gained, refinement and amendments will be required. This proposed process of standardization will facilitate comparative effectiveness research and encourage high-quality meta-analysis of individual patient data.

Common data elements for traumatic brain injury: recommendations from the interagency working group on demographics and clinical assessment.

Comparing results across studies in traumatic brain injury (TBI) has been difficult because of the variability in data coding, definitions, and collection procedures. The global aim of the Working Group on Demographics and Clinical Assessment was to develop recommendations on the coding of clinical and demographic variables for TBI studies applicable across the broad spectrum of TBI, and to classify these as core, supplemental, or emerging. The process was consensus driven, with input from experts over a broad range of disciplines. Special consideration was given to military and pediatric TBI. Categorizing clinical elements as core versus supplemental proved difficult, given the great variation in types of studies and their interests. The data elements are contained in modules, which are grouped together in categories. Three levels of detail for coding data elements were developed: basic, intermediate, and advanced, with the greatest level of detail in the advanced version. In every case, the more detailed coding can be collapsed into the basic version. Templates were produced to summarize coding formats, motivation of choices, and recommendations for procedures. Work is ongoing to include more international participation and to provide an electronic data entry format with pull-down menus and automated data checks. This proposed standardization will facilitate comparison of research findings across studies and encourage high-quality meta-analysis of individual patient data.

Mortality over four decades after traumatic brain injury rehabilitation: a retrospective cohort study.

OBJECTIVE: To investigate mortality, life expectancy, risk factors for death, and causes of death in persons with traumatic brain injury (TBI). DESIGN: Retrospective cohort study. SETTING: Used data from an inpatient rehabilitation facility, the Social Security Death Index, death certificates, and the U.S. population age-race-sex-specific and cause-specific mortality rates. PARTICIPANTS: Persons with TBI (N=1678) surviving to their first anniversary of injury admitted to rehabilitation from an acute care hospital within 1 year of injury between 1961 and 2002. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Vital status, standardized mortality ratio, life expectancy, cause of death. RESULTS: Persons with TBI were 1.5 times more likely to die than persons in the general population of similar age, sex, and race, resulting in an estimated average life expectancy reduction of 4 years. Within the TBI population, the strongest independent risk factors for death after 1 year postinjury were being older, being male, having less education, having a longer hospitalization, having an earlier year of injury, and being in a vegetative state at rehabilitation discharge. After 1 year postinjury, persons with TBI were 49 times more likely to die of aspiration pneumonia, 22 times more likely to die of seizures, 4 times more likely to die of pneumonia, 3 times more likely to commit suicide, and 2.5 times more likely to die of digestive conditions than persons in the general population of similar age, sex, and race. CONCLUSIONS: This study demonstrated life expectancy after TBI rehabilitation is reduced and associated with specific risk factors and causes of death.

Treatment efficacy of social communication skills training after traumatic brain injury: a randomized treatment and deferred treatment controlled trial.

OBJECTIVE: To evaluate the efficacy of a replicable group treatment program to improve social communication skills after traumatic brain injury (TBI). DESIGN: Randomized treatment and deferred treatment controlled trial, with follow-up at 3, 6, and 9 months post-treatment. SETTING: Community. PARTICIPANTS: Volunteer sample of 52 people with TBI who were at least 1 year postinjury, who received rehabilitation, and who had identified social communication deficits. INTERVENTION: Twelve weekly group sessions (1.5 h each) to improve social communication. MAIN OUTCOME MEASURES: The Profile of Functional Impairment in Communication (PFIC), Social Communication Skills Questionnaire-Adapted (SCSQ-A), Goal Attainment Scale (GAS), Craig Handicap Assessment and Reporting Technique-Short Form social integration and occupation subscales, Community Integration Questionnaire social integration and productivity subscales, and Satisfaction With Life Scale (SWLS). RESULTS: Independent samples t test analysis showed significant treatment effect compared with no treatment on 7 of 10 of the PFIC subscales (P range, .024 to <.001) and the SCSQ-A (P=.005) after the first 12 weeks of the study. After 12 weeks of treatment for all participants, repeated-measures analysis showed significant improvements from baseline on 9 of 10 PFIC subscales (P range, .01-.001), SCSQ-A (P < or = .001), GAS (P < or = .001), and SWLS (P = .011). At 6-month follow-up, scores were significantly better than baseline on 6 of 10 PFIC scales (P range, .01-.001), the SCSQ-A (P < or = .001), GAS (P < or = .001), and SWLS (P < or = .001). CONCLUSIONS: TBI subjects who received social communication skills training had improved communication skills that were maintained on follow-up. Overall life satisfaction for participants was improved.

Quantifying environmental factors: a measure of physical, attitudinal, service, productivity, and policy barriers.

OBJECTIVE: To develop and test a new instrument to assess environmental barriers encountered by people with and without disabilities by using a questionnaire format. DESIGN: New instrument development. SETTING: A rehabilitation hospital and community. PARTICIPANTS: Two convenience samples: (1) 97 subjects, 50 with disabilities and 47 without disability, and (2) 409 subjects with disabilities from spinal cord injury, traumatic brain injury, multiple sclerosis, amputation, or auditory or visual impairments. In addition, a population-based sample in Colorado of 2269 people (mean age, 44 y; 57% men) with and without disabilities. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Item development; factor structure; test-retest, subject-proxy and internal consistency reliability; content, construct, and discriminant validity; and subscale and abbreviated version development. RESULTS: Panels of experts on disability developed items for the Craig Hospital Inventory of Environmental Factors (CHIEF). The instrument measured the frequency and magnitude of environmental barriers reported by individuals. Five subscales were derived from factor analysis measuring (1) attitudes and support, (2) services and assistance, (3) physical and structural, (4) policy, and (5) work and school environmental barriers. The CHIEF total score had high test-retest reliability (intraclass correlation coefficient [ICC]=.93) and high internal consistency (Cronbach alpha=.93), but lower participant-proxy agreement (ICC=.62). Significant differences were found in CHIEF scores among groups of people with known differences in disability levels and disability categories. CONCLUSIONS: The CHIEF has good test-retest and internal consistency reliability with evidence of content, construct, and discriminant validity resulting from its development strategy and psychometric assessments in samples of the general population and among people with a variety of disabilities.