Retrospective baseline measurement of self-reported health status and health-related quality of life versus population norms in the evaluation of post-injury losses.

Background: Owing to the difficulty in prospectively measuring pre-injury health status and health-related quality of life (HRQL) in an injured cohort, population norms or retrospective baseline scores are often used as comparators for evaluating post-injury losses. However, there has been little discussion in the literature or research into the soundness of these approaches for this purpose. Objectives: To investigate the appropriateness of the retrospectively measured baseline health status and HRQL in an injured population for the purpose of evaluating post-injury losses. Methods: A cohort of injured admitted to hospital (n = 186) was followed up for 12 months after injury. Retrospectively measured pre-injury health status and HRQL scores were compared with those at 12 months after injury for participants who reported complete recovery (n = 61) and those who did not. Retrospective baseline scores for the whole cohort were also compared with Australian population norms. Results: For participants who completely recovered, no significant difference was observed between scores at baseline (measured retrospectively) and those at 12 months after injury (36-item Short Form Questionnaire physical component summary z= -1.274, p=0.203 36-item Short Form Questionnaire mental component summary z= -1.634, p=0.102 Short Form 6 Dimensions: z= -1.405, p=0.296). A borderline significant difference was observed in HRQL as measured by the Assessment of Quality of Life (z = -1.970, p = 0.049). Retrospectively measured pre-injury scores were consistently higher than Australian norms for all measures. Conclusions: The injured population may not be representative of the general population. Consequently, retrospective baseline measurement of pre-injury health states may be more appropriate than general population norms for the purpose of evaluating post-injury losses in this population. [ABSTRACT FROM AUTHOR]