The burden of somatic comorbidities in patients surviving a traumatic brain injury

Abstract

Background: The long-term development of somatic comorbidities in patients surviving a traumatic brain injury (TBI) may contribute to both the individual and public health burden; however, a systematic investigation has not yet been undertaken.

Methods: We investigated the long-term burden of somatic comorbidities in patients surviving a TBI. We included all Danish residents (≥ 18.0 years) who were hospitalized with a TBI between 1994 and 2018 and survived beyond discharge (n = 153,177). TBIs were defined within a selected list of ICD-10 codes. Each TBI patient was age-matched to five non-TBI Controls ("Controls", n = 752,224). The following age groups were considered: 18.0-39.9, 40.0-69.9, and ≥ 70.0. Within each age group, we analyzed (1) TBI patients vs Controls and (2) subsequently categorized patients based on their length of stay (LOS) to better capture that patients with more severe injuries stay longer in the hospital (vs Controls). Somatic comorbidities within the Charlson Comorbidity Index (CCI) were considered. Adjusted odds ratios for developing cerebrovascular disease, cancer, diabetes, and cardiovascular disease were obtained using binomial regression. Using all CCI conditions, we employed a recurrent event regression weighted by the corresponding CCI scores to estimate the adjusted mean cumulative CCI score since index.

Results: The landscape of CCI conditions shifts in TBI survivors and is predominated by a higher long-term odds ratio of developing cerebrovascular disease, especially non-traumatic intracerebral hemorrhage (ICH), even 10 years post-index; the risk is correlated with LOS. Cancer risk is significantly lower in TBI survivors. Irrespective of age group, the mean cumulative CCI score is significantly higher in TBI survivors.

Conclusion: The indirect consequences of surviving a TBI extend far beyond the immediate post-index period by exacerbating functional decline in survivors through the compounding effect of somatic comorbidities that cumulatively affect the capacity to function physically, cognitively, or socially. TBI emerge as an independent risk factor for developing ICH.

Keywords: Cerebrovascular; Comorbidity; Intracerebral hemorrhage; Stroke; TBI; Traumatic brain injury.

Fig. 1

The crude distribution of comorbidities shown in successive 1-year intervals over the 10-year post-index period. The comorbidities included only those recorded after index date, imposing that its first documentation was registered post-index. Conditions that pre-dated the index date were excluded and were not eligible for post-index registration for that specific individual

Fig. 2

The risk of non-traumatic intracerebral hemorrhage (ICD10: I61, I62). A: Proportion of Controls and individuals in the TBI severity groups with intracerebral hemorrhage. B: The probability of intracerebral hemorrhage at specific time points, comparing the TBI severity groups with Controls

Fig. 3

The risk of cerebral infarction (ICD10: I63). A: Proportion of Controls and individuals in the TBI severity groups with cerebral infarction. B: The probability of cerebral infarction at specific time points, comparing the TBI severity groups with Controls

Fig. 4

The risk all-type cancer (with and without metastasis) as defined within the CCI framework (Supplementary Table 2). A: Proportion of Controls and individuals in the TBI severity groups with cancer. B: The probability of cancer at specific time points, comparing the TBI severity groups with Controls