Prognostic factors of long-term functioning and productivity after traumatic brain injury: a systematic review of prospective cohort studies

Objective: To systematically review prospective cohort studies that investigated prognostic factors associated with long-term activity limitations or participation restrictions and productivity after a traumatic brain injury.Data sources: PubMed and Psychinfo were searched from 1995 to April 2005, and references were checked.Review methods: Publications were selected if the study assessed prognostic factors for activity limitations or participation restrictions at least one year post injury; outcome was measured with another or additional measure besides the Glasgow Outcome Scale; the design was a prospective cohort study of adult traumatic brain injury patients; the article was a full-text article written in English, French, German or Dutch. Two reviewers independently assessed methodological quality. A study was considered as 'high quality' if it satisfied at least half of the maximum available quality score.Results: Thirty-five articles reporting on 14 cohorts were included. Due to heterogeneity in prognostic factors and outcome measures, a best-evidence synthesis was performed. All cohorts were of high quality. Strong evidence for predicting disability was found for older age, pre-injury unemployment, pre-injury substance abuse, and more disability at rehabilitation discharge. Strong prognostic factors for being non-productive were pre-injury unemployment, longer post-traumatic amnesia, more disability at rehabilitation admission, and pre-injury substance abuse.Conclusion: Older age, pre-injury unemployment, pre-injury substance abuse and more disability at rehabilitation discharge are important predictors of long-term disability. Pre-injury unemployment, longer post-traumatic amnesia, more disability at rehabilitation admission and pre-injury substance abuse are important predictors of being non-productive.