Psychometric properties of questionnaires evaluating health-related quality of life and functional status in polytrauma patients with lower extremity injury

To establish the unidimensionality, internal consistency and validity of two health-related quality of life measures and one functional status questionnaire among polytrauma patients.186 Patients with severe polytrauma including lower extremity injury completed the Sickness Impact Profile-136 (SIP-136), the Medical Outcomes Study 36-Item Short Health Survey (SF-36) and the Groningen Activity Restriction Scale (GARS) 15 months after injury. Unidimensionality and internal consistency was assessed by principal components analysis and Cronbach's alpha (α). To test the construct validity of the questionnaires, predetermined hypotheses were tested.The unidimensionality and internal consistency of the GARS and the SF-36, but not the SIP-136 were supported. The construct validity of the SF-36, GARS and to a lesser extent the SIP-136 was confirmed.The SF-36 and the GARS appear to be preferable for use in polytrauma patients over the SIP-136.People who sustain traumatic injury do not generally regain their pre-injury levels of physical functioning and experience difficulty in performing activities of daily living (ADL) [1,2]. Previous studies have suggested that the lower extremities are the most frequently injured body regions in polytrauma patients [3]. In addition, injuries of the lower extremities are believed to have a major impact on functional status and health-related quality of life (HRQoL) [3,4].The Sickness Impact Profile-136 (SIP-136) [5] and the Medical Outcomes Study 36-Item Short Health Survey (SF-36) [6] are widely used measures of HRQoL and have been used in populations with a wide range of diagnoses and disease severity including trauma care [1,2]. The Groningen Activity Restriction Scale (GARS) [7,8] is a questionnaire, which measures patient's functional limitations of socially defined roles and tasks and is used in various countries in different populations. However, any instrument that is used to assess patients should have adequate psychometric properti