Effects of age on survival and neurological recovery of individuals following acute traumatic spinal cord injury

Concomitant traumatic brain injury as a determinant of survival, and neurological and functional outcomes after traumatic spinal cord injury: A retrospective cohort study

BACKGROUND

Although concomitant traumatic brain injury (TBI) is not infrequently associated with spinal cord injury (SCI), there is relatively scarce information about the effects of concomitant TBI on outcomes after SCI.

OBJECTIVE

To assess the impact of concomitant mild-to-moderate TBI on survival, and neurological and functional outcomes within the first year after acute traumatic SCI.

DESIGN

Retrospective cohort study.

SETTING

Acute spine trauma centers in the United States.

PARTICIPANTS

This study includes all individuals who were enrolled into the Third National Spinal Cord Injury Study (NASCIS-3). The study population was classified into SCI + TBI group and SCI-alone group. TBI was defined as a Glasgow Coma Scale score <15 on admission.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Both groups were compared regarding their survival and neurological outcomes (ie, NASCIS motor, sensory and pain scores) and functional outcome (ie, Functional Independence Measure score) within the first year following SCI. Data analyses were adjusted for major potential confounders.

RESULTS

There were 413 individuals in the SCI-alone group and 86 individuals in the SCI + TBI group (17.2%). Both groups were comparable regarding gender distribution (p = .621). However, the SCI + TBI group was older (p < .001), had a higher proportion of complete (p = .006) and cervical SCI (p = .003), and had a higher blood alcohol level (p < .001) than the SCI-alone group. The SCI + TBI group did not significantly differ from the SCI-alone group regarding survival within the first year after SCI (p = .768). Among the survivors, concomitant mild-to-moderate TBI did not significantly affect neurological and functional outcomes at 1 year after SCI in the multiple regression analyses after adjusting for major potential confounders.

CONCLUSIONS

The results of this study suggest that concomitant mild-to-moderate TBI did not have a significant impact on survival, neurological recovery, and functional outcomes at 1 year after SCI, even though there were some epidemiological differences between SCI-alone and SCI + TBI groups.

Racial and Ethnical Discrepancies and Similarities in the Epidemiology, Survival, and Neurological Outcomes After Acute Traumatic Spinal Cord Injury: A Retrospective Cohort Study Using Data from the NASCIS-1 Trial

Background

Little is known about the impact of race/ethnicity on the clinical and neurological outcomes after acute traumatic spinal cord injury (tSCI).

Objectives

This study examined the influence of race/ethnicity on the individuals' survival and neurological recovery within the first year after tSCI.

Methods

The 306 cases enrolled in the First National Acute Spinal Cord Injury Study (NASCIS-1) were grouped as African American individuals (n = 84), non-Hispanic White individuals (n = 159), and other races/ethnicities that included Hispanic individuals (n = 60) and Asian individuals (n = 3). Outcome measures included survival and neurological recovery within the first year after tSCI. Data analyses were adjusted for major potential confounders.

Results

There were 39 females and 267 males with mean age of 31 years who mostly sustained cervical severe tSCI after motor vehicle accidents or falls. The three groups were comparable regarding sex distribution, level and severity of tSCI, level of consciousness at admission, and total received dose of methylprednisolone. African American individuals were significantly older than non-Hispanic White individuals (p = .0238). African American individuals and individuals of other races/ethnicities more often had a tSCI with open wound caused by missile and water-related accidents than non-Hispanic White individuals (p < .0001). Survival rates within the first year after tSCI were comparable among the three groups (p = .3191). Among the survivors, there were no significant differences among the three groups regarding motor and pinprick and light-touch sensory recovery (p > .0500).

Conclusions

The results of this study suggest that, while there were few differences among the racial/ethnical groups regarding the epidemiology of tSCI, race/ethnicity did not influence survival rate or neurological recovery within the first year post-tSCI.

Sex-Related Discrepancies in the Access to Optimal Care and Outcomes After Traumatic Spinal Cord Injury: A Retrospective Cohort Study Using Data From a Canadian Registry

OBJECTIVE

To compare males and females who were stratified into subgroups corresponding to premenopausal, perimenopausal, and postmenopausal ages, regarding access to optimal care and their outcomes after traumatic spinal cord injury (tSCI).

STUDY DESIGN

Retrospective cohort study.

SETTING

Eighteen acute care centers and 13 rehabilitation facilities across Canada.

PARTICIPANTS

This study included 5571 individuals with tSCI at C1-L2 who were enrolled in the Rick Hansen Spinal Cord Injury Registry from July 2004 to September 2019 (N=5571). Females were compared with males in the younger (aged ≤40 years), middle-aged (ages 41-50), and older (aged >50 years) subgroups.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Females were compared with males in each subgroup with regard to their demographic data, pre-existing comorbidities, injury characteristics, management choices, access to optimal care, and clinical, neurologic, and functional outcomes after tSCI.

RESULTS

In the younger subgroups, females (n=408) were significantly younger, had a greater proportion of aboriginals and transportation-related tSCIs, underwent surgical treatment more often, and had a greater sensory score change than males (n=1613). In the middle-aged subgroups, females (n=174) had a greater proportion of high-thoracic tSCIs than males (n=666). In the older subgroups, females (n=660) were significantly older, had more fall-related and less severe tSCIs, had a shorter stay at the rehabilitation center, had less spasticity, and were discharged home less often than males (n=2050).

CONCLUSIONS

The results of this study suggest some sex-related differences in individuals' demographics and injury characteristics, but fewer discrepancies between females and males regarding their access to optimal care and outcomes after tSCI. Overall, future clinical trials could consider inclusion of males and females of all age groups to enhance recruitment and augment generalizability.

Improving translatability of spinal cord injury research by including age as a demographic variable

Pre-clinical and clinical spinal cord injury (SCI) studies differ in study design, particularly in the demographic characteristics of the chosen population. In clinical study design, criteria such as such as motor scores, neurological level, and severity of injury are often key determinants for participant inclusion. Further, demographic variables in clinical trials often include individuals from a wide age range and typically include both sexes, albeit historically most cases of SCI occur in males. In contrast, pre-clinical SCI models predominately utilize young adult rodents and typically use only females. While it is often not feasible to power SCI clinical trials to test multi-variable designs such as contrasting different ages, recent pre-clinical findings in SCI animal models have emphasized the importance of considering age as a biological variable prior to human experiments. Emerging pre-clinical data have identified case examples of treatments that diverge in efficacy across different demographic variables and have elucidated several age-dependent effects in SCI. The extent to which these differing or diverging treatment responses manifest clinically can not only complicate statistical findings and trial interpretations but also may be predictive of worse outcomes in select clinical populations. This review highlights recent literature including age as a biological variable in pre-clinical studies and articulates the results with respect to implications for clinical trials. Based on emerging unpredictable treatment outcomes in older rodents, we argue for the importance of including age as a biological variable in pre-clinical animal models prior to clinical testing. We believe that careful analyses of how age interacts with SCI treatments and pathophysiology will help guide clinical trial design and may improve both the safety and outcomes of such important efforts.