Predictors and indicators of disability and quality of life 4 years after a severe traumatic brain injury. A Structural Equation Modelling analysis from the PariS-TBI study
Prof Philippe AZOUVIa, Dr Claire JOURDANa, Dr Idir GHOUTb, Mrs Emmanuelle DARNOUXc, Dr Sylvie AZERADb, Prof Philippe AEGERTERb, Dr Jean-Jacques WEISSc, Dr Claire VALLAT-AZOUVId, Dr Eleonore BAYENe, Prof Pascale PRADAT-DIEHLe
a Hopital Raymond Poincaré, b URC Paris-Ouest, c CRFTC, d UGECAMIDF, e Hopital Pitie-Salpétrière
Objective: To assess the predictors and indicators of disability and quality of life four years after a severe traumatic brain injury (TBI), using a Structural Equation Modelling (SEM). SEM is a multivariate approach permitting to take into account the complex inter-relationships between individual predictors, in order to disentangle factors which ahev a direct or indirect relationship with the dependant variable.
Methods: The Paris TBI study is a longitudinal inception cohort study of 504 patients with severe TBI in the Parisian area (1). Among 245 survivors, 147 patients were assessed four years post-injury. Two outcome measures were analysed separately using SEM: the Glasgow Outcome Scale- extended (GOS-E) (2), which is a global measure of disability after TBI, and the QOLIBRI, a disease-specific measure of quality of life after TBI (3). Four groups of variable were entered in the model: demographics; injury severity; psychological and cognitive impairments; somatic impairments.
Results: The GOS-E was directly significantly related to all four groups of variables (age, gender, severity of injury, psycho-cognitive and somatic impairments). Education duration had an indirect effect, mediated by psycho-cognitive impairments. In contrast, the QOLIBRI was only directly predicted by psycho-cognitive impairments. Age and somatic impairments had an indirect influence on the QOLIBRI, via psycho-cognitive impairments.
Discussion/Conclusion: Disability and quality of life were directly influenced by different factors. While disability appeared to result from an interaction of a wide range of factors, including demographics, injury severity, psycho-cognitive and somatic deficiencies, quality of life was solely directly related to psycho-cognitive factors. Other factors, such as age and somatic impairments only had an indirect effect.
1. Jourdan et al. Referral to rehabilitation after severe traumatic brain injury: results from the PariS-TBI Study. Neurorehabil Neural Repair. 2013 Jan;27(1):35-44.
2. Wilson et al. Structured interview for the Glasgow Outcome Scale and the Extended Glasgow Outcome Scale: Guidelines for their use. Journal of Neurotrauma. 1998;15:573-85.
3. von Steinbuchel et al. Quality of Life after Brain Injury (QOLIBRI): scale validity and correlates of quality of life. J Neurotrauma. 2010 Jul;27(7):1157-65.
Keywords : traumatic brain injury; disability; quality of life