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.