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.

Life Expectancy after Stroke Based On Age, Sex, and Rankin Grade of Disability: A Synthesis.

BACKGROUND: Stroke is a leading cause of death and disability in the developed world. The major factor affecting long term survival (other than age) is known to be the severity of disability. Yet to our knowledge there are no studies reporting life expectancies stratified by both age and severity. Remaining life expectancy is a key measure of health. METHODS: We identified 11 long-term follow-up studies of stroke patients that reported the multivariate effects of age, sex, the modified Rankin Scale (mRS) grade of disability, and other factors. From these we computed the composite effects of these factors on survival, then used these to calculate age-, sex-, and mRS-specific mortality rates. Finally we used the rates to construct life tables, and hence obtain life expectancies. RESULTS: Life expectancy varies by age, sex, and mRS. The life expectancies of males age 70, for example, were 13, 13, 11, 8, 6, and 5 years for Rankin Grades 0-5, respectively, representing reductions of 1, 1, 3, 6, 8, and 9 years from the corresponding general population figure. CONCLUSIONS: These figures demonstrate the importance of rehabilitation following stroke, and can be used in discussion of public policy and benchmarking of future results.

An update on survival after anoxic brain injury in adolescents and young adults.

While much is known about long-term survival after traumatic brain injury, less is known about survival after anoxic/hypoxic brain injury. We previously compared the two and found no significant difference (hazard ratio [HR] 0.97, p=0.92) after controlling for age, sex, and severity of disability. The present study updates this, based on 1,802 patients with TBI and 380 with anoxic, aged 15 to 25, evaluated in 1986 or later, and who survived one year post injury. The anoxic group had higher mortality (HR = 1.13), though again the difference was not statistically significant (p=0.58).

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.

Improvements in long-term survival after spinal cord injury?

OBJECTIVE: To investigate whether there have been improvements in long-term survival after spinal cord injury in recent decades. DESIGN: Survival analysis using time-varying covariates. The outcome variable was survival or mortality, and the explanatory variables were age, sex, level and grade of injury, and calendar year. The data were analyzed using the logistic regression model, Poisson regression model with comparison to the general population, and the computation of standardized mortality ratios for various groups. SETTING: National Spinal Cord Injury Model Systems facilities. PARTICIPANTS: Persons (N=31,531) who survived 2 years postinjury, were older than 10 years, and who did not require ventilator support. These persons contributed 484,979 person-years of data, with 8536 deaths over the 1973 to 2012 study period. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Survival; survival relative to the general population; life expectancy. RESULTS: After adjustment for age, sex, race, etiology of injury, time since injury, and level and grade of injury, mortality in persons with spinal cord injury was higher in the 2005 to 2012 period than in 1990 to 2004 or 1980 to 1989, the odds ratios for these 3 periods were .857, .826, and .802 as compared with the 1970 to 1979 reference period. CONCLUSIONS: There was no evidence of improvement. Long-term survival has not changed over the past 30 years.

Recent trends in cerebral palsy survival. Part I: period and cohort effects.

AIM: To determine whether the trend of improved survival among individuals with cerebral palsy (CP) in California during the 1980s and 1990s has continued during the most recent decade. METHOD: In an observational cohort study we evaluated individuals with CP, aged 4 years and older, who were clients of the California Department of Developmental Services. Medical diagnoses, functional disabilities, and special health care requirements were assessed with Client Development Evaluation Reports made between 1983 and 2010. Trends in birth cohort survival were analyzed with Kaplan-Meier curves and Cox regression. Calendar year period effects were analyzed with Poisson regression. RESULTS: A total of 51,923 persons with CP (28,789 males [55%], 23,134 females [45%]; mean age 14y 11mo, SD 14y 1mo, range 4y 0mo to 96y 10mo) collectively contributed 662,268 years of follow-up. There were 7690 deaths for an overall mortality rate of 11.6 per 1000 persons per year. No significant birth cohort effects on survival were observed in 4-year-olds who had no severe disabilities. By contrast, children who did not lift their heads in prone position who were born in more recent years had significantly lower mortality rates (Cox hazard ratio 0.971, p<0.001) than those with comparable disabilities born earlier. With regard to calendar year period effects, we found that age-, sex-, and disability-specific mortality rates declined by 1.5% (95% CI 0.9-2.1) year-over-year from 1983 to 2010. The estimate increased to 2.5% (95% CI 1.9-3.1) per year when we additionally controlled for tube-feeding status. Mortality rates in tube fed adolescents and adults, ages 15 to 59 years, declined by 0.9% (95% CI, 0.4-1.4) per year. No improvement was observed for adolescents or adults who fed orally or for those over age 60. In fact, the ratio of age-specific mortality rates for these latter groups to those in the general population, increased by 1.7% (95% CI 1.3-2.0) per year during the study period. INTERPRETATION: The trend toward improved survival has continued throughout the most recent decade. Declines in CP childhood mortality are comparable to the improvements observed in the United States general population (i.e. the mortality ratio in childhood has remained roughly constant over the last three decades). In contrast, the mortality ratio for most adolescents and adults with CP, relative to the general population, has increased.

Recent trends in cerebral palsy survival. Part II: individual survival prognosis.

AIM: The aim of the study was to determine survival probabilities and life expectancies for individuals with cerebral palsy based on data collected over a 28-year period in California. METHOD: We identified all individuals with cerebral palsy, aged 4 years or older, who were clients of the California Department of Developmental Services between 1983 and 2010. Kaplan-Meier survival curves were constructed for 4-year-old children, and the estimated survival probabilities were adjusted to reflect trends in mortality by calendar year. For persons aged 15, 30, 45, and 60 years, separate Poisson regression models were used to estimate age-, sex-, and disability-specific mortality rates. These mortality rates were adjusted to reflect trends of improved survival, and life expectancies were obtained using life table methods. RESULTS: The sample comprised 16,440, 14,609, 11,735, 7023, and 2375 persons at ages 4, 15, 30, 45, and 60 years, respectively. In 1983, 50% of 4-year-old children who did not lift their heads in the prone position and were tube fed lived to age 10.9 years. By 2010, the median age at death had increased to 17.1 years. In ambulatory children the probability of survival to adulthood did not change by more than 1%. Life expectancies for adolescents and adults were lower for those with more severe limitations in motor function and feeding skills, and decreased with advancing age. Life expectancies for tube-fed adolescents and adults increased by 1 to 3 years, depending on age and pattern of disability, over the course of the study period. INTERPRETATION: Over the past three decades in California there have been significant improvements in the survival of children with very severe disabilities. There have also been improvements to the life expectancy of tube-fed adults, though to a lesser extent than in children.

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).

Survival of individuals with cerebral palsy receiving continuous intrathecal baclofen treatment: a matched-cohort study.

AIM: To determine whether intrathecal baclofen (ITB) changes mortality risk in persons with cerebral palsy (CP). METHOD: Records were reviewed for all persons with CP who were managed with ITB for hypertonicity at a specialty hospital in Minnesota between May 1993 and August 2007. A comparison cohort was randomly selected from clients of the California Department of Developmental Services who were initially evaluated between 1987 and 1990 and were matched to those with ITB for age, sex, Gross Motor Function Classification System (GMFCS) level, presence or absence of epilepsy, and feeding-tube use. Survival probabilities were estimated using the Kaplan-Meier method, and differences were tested via log-rank. RESULTS: Three hundred and fifty-nine persons with CP (202 males, 157 females) receiving ITB for hypertonicity (mean age 12y 8mo, SD 7y 9mo, range 3y 1mo to 39y 9mo) were matched to 349 persons without ITB pumps (195 males, 154 females; mean age 12y 7mo, SD 8y 4mo, range 2y 7mo to 40y). The proportion of patients at different GMFCS levels in the ITB and in the non-ITB cohorts, respectively, was as follows: level II 3% and 3%, level III 16% and 16%, level IV 38% and 37%, and level V 43% and 44%. Survival at 8 years of follow-up was 92% (SD 1.9%) in the ITB cohort and 82% (SD 2.4%) in the non-ITB cohort (p<0.001). After adjustment to account for recent trends in improved survival in CP, 8-year survival in the non-ITB cohort was 88%, which was not significantly different from the ITB cohort (p=0.073). INTERPRETATION: ITB therapy does not increase mortality in individuals with CP and may suggest an increase in life expectancy.

Cognitive impairment and mortality in the Cardiovascular Health Study.

Cognitive impairment is associated with increased mortality, depending on the severity of impairment. We analyzed data from the Cardiovascular Health Study (CHS), using Cox proportional hazards regression models to quantify the effect of the impairment. After adjustment for age, sex, and medical risk factors, we found the resulting relative risks to range from 1.19 for mild impairment to 1.98 for severe.

Smoking habit and mortality: a meta-analysis.

Cigarette smoking leads to excess mortality risk. Although it is well known that the risk increases with the number of pack-years of smoking--that is, how much a person smokes, or "habit"--there is apparently no published studies that organize and synthesize the evidence on this topic. This paper provides a meta-analysis of the latest published findings relating to cigarette smoking habit and excess mortality. A combined estimate of the relative risk (RR) of death for smokers, stratified by habit (light, medium, or heavy smoking), compared with non-smokers is provided.

Underwriting the presidents.

The United States has had 43 presidents. We examined whether they survive significantly longer or shorter than their contemporaries. We found that survival was better for presidents elected in the 1789-1841 and 1933-2001 periods (SMRs of 0.7 and 0.6, respectively), but worse for those elected in 1845-1929 (SMR = 2.9). We also found increased mortality during the years lived in office (SMR = 1.4), but no increase in mortality after leaving office (SMR = 1.0).

Long-term survival after childhood spinal cord injury.

OBJECTIVE: To determine whether persons who incur a spinal cord injury as children are at increased risk of mortality compared with persons injured as adults given comparable current age, sex, and injury severity. METHODS: A total of 25,340 persons admitted to the National Spinal Cord Injury Statistical Center database or the National Shriners Spinal Cord Injury database who were not ventilator dependent and who survived more than 2 years after injury were included in this study. These persons contributed 274,020 person-years of data, with 3844 deaths, over the 1973-2004 study period. Data were analyzed using pooled repeated observations analysis of person-years. For each person-year the outcome variable was survival/mortality, and the explanatory variables included current age, sex, race, cause of injury, severity of injury, and age at injury (the focus of the current analysis). RESULTS: Other factors being equal, persons who were less than 16 years of age at time of injury had a 31% (95% CI = 3%-65%) increase in the annual odds of dying compared with persons injured at older ages (P= 0.013). This increased risk did not vary significantly by current age, sex, race, injury severity, or era of injury (P > 0.05). CONCLUSION: Life expectancy for persons injured as children appears to be slightly lower than that of otherwise comparably injured persons who suffered their injuries as adults. Nonetheless, persons who are injured young can enjoy relatively long life expectancies, ranging from approximately 83% of normal life expectancy for persons with minimal deficit incomplete injuries to approximately 50% of normal in high-cervical-level injuries without ventilator dependence.

Worklife after traumatic spinal cord injury.

OBJECTIVE: To develop predictive models to estimate worklife expectancy after spinal cord injury (SCI). DESIGN: Inception cohort study. SETTING: Model SCI Care Systems throughout the United States. PARTICIPANTS: 20,143 persons enrolled in the National Spinal Cord Injury Statistical Center database since 1973. INTERVENTION: Not applicable. MAIN OUTCOME MEASURE: Postinjury employment rates and worklife expectancy. RESULTS: Using logistic regression, we found a greater likelihood of being employed in any given year to be significantly associated with younger age, white race, higher education level, being married, having a nonviolent cause of injury, paraplegia, ASIA D injury, longer time postinjury, being employed at injury and during the previous postinjury year, higher general population employment rate, lower level of Social Security Disability Insurance benefits, and calendar years after the passage of the Americans with Disabilities Act. CONCLUSIONS: The likelihood of postinjury employment varies substantially among persons with SCI. Given favorable patient characteristics, worklife should be considerably higher than previous estimates.

Long-term survival of persons ventilator dependent after spinal cord injury.

BACKGROUND/OBJECTIVE: Identify factors related to long-term survival, and quantify their effect on mortality and life expectancy. SETTING: Model spinal cord injury systems of care across the United States. STUDY DESIGN: Survival analysis of persons with traumatic spinal cord injury who are ventilator dependent at discharge from inpatient rehabilitation and who survive at least 1 year after injury. METHODS: Logistic regression analysis on a data set of 1,986 person-years occurring among 319 individuals injured from 1973 through 2003. RESULTS: The key factors related to long-term survival were age, time since injury, neurologic level, and degree of completeness of injury. The life expectancies were modestly lower than previous estimates. Pneumonia and other respiratory conditions remain the leading cause of death but account for only 31% of deaths of known causes. CONCLUSIONS: Whereas previous research has suggested a dramatic improvement in survival over the last few decades in this population, this is only the case during the critical first few years after injury. There was no evidence for such a trend in the subsequent period.

Computing exact excess death rates from a published mortality study.

We wish to estimate the associated excess death rate (EDR) or mortality ratio (MR) from a published study of persons with a given medical condition. This requires computation of the expected mortality in the study population. If age- and sex-specific person years of data are available, this task is straightforward. Most often, however, we have only descriptive statistics--percentage male, average and standard deviation of age--at the beginning of follow up. We show here how this limited information can be used to compute an exact EDR or other quantities of interest.