Interpreting Quality of Life after Brain Injury Scores: Cross-Walk with the Short Form-36.

The Quality of Life after Brain Injury (QOLIBRI) instruments are traumatic brain injury (TBI)-specific assessments of health-related quality of life (HRQoL), with established validity and reliability. The purpose of the study is to help improve the interpretability of the two QOLIBRI summary scores (the QOLIBRI Total score and the QOLBRI Overall Scale [OS] score). An analysis was conducted of 761 patients with TBI who took part in the QOLIBRI validation studies. A cross-walk between QOLIBRI scores and the SF-36 Mental Component Summary norm-based scoring system was performed using geometric mean regression analysis. The exercise supports a previous suggestion that QOLIBRI Total scores <60 indicate low or impaired HRQoL and indicate that the corresponding score on the QOLIBRI-OS is <52. The percentage of cases in the sample that fell into the "impaired HRQoL" category was 36% for the Mental Component Summary, 38% for the QOLIBRI Total, and 39% for the QOLIBRI-OS. Relationships between the QOLIBRI scales and the Glasgow Outcome Scale-Extended (GOSE), as a measure of global function, are presented in the form of means and standard deviations that allow comparison with other studies, and data on age and sex are presented for the QOLIBRI-OS. While bearing in mind the potential imprecision of the comparison, the findings provide a framework for evaluating QOLIBRI summary scores in relation to generic HRQoL that improves their interpretability.