Identifying the concepts contained within health-related quality of life outcome measures in concussion research using the International Classification of Functioning, Disability, and Health as a reference: a systematic review.

PURPOSE: To identify the concepts contained within health-related quality of life (HRQOL) outcome measures used in concussion-specific research using the International Classification of Functioning, Disability, and Health (ICF) as a reference. METHODS: Eight electronic databases were searched from January 1, 1992 to March 12, 2017. Gray literature was searched, reference lists scanned, and relevant journals hand-searched. Agreement for inclusion was reached by consensus by two reviewers. A standardized data extraction tool was used to document study design, population, and key findings. Questionnaire items were linked as concepts to the corresponding second-level category of the ICF. Quality of studies was not assessed, as review was exploratory. RESULTS: Five outcome measures met the inclusion criteria, including the Perceived Quality of Life Scale, EuroQoL-5 dimensions, Quality of Life after Brain Injury, WHOQOL-100, and WHOQOL-BREF. A total of 373 concepts were extracted. 34 questions were linked to activities and participation (50.7%), 16 questions (23.9%) referred to body functions, and 17 questions (25.4%) were related to the environment. CONCLUSIONS: The wide range of concepts covered by different outcome measures demonstrates the complexity of recovery post-concussion and a lack of universal agreement in terms of what should be measured in this population. A working conceptual model of HRQOL post-concussion is proposed. Registration Prospero #CRD42017068241 (June 15, 2017).