Patient-Proxy Agreement on the Health-Related Quality of Life One Year After Traumatic Brain Injury

Objective: To examine the level of agreement between patients and their proxies on a measure of health-related quality of life (HRQL) 1 year after traumatic brain injury (TBI). Design: A cross-sectional study. Setting: Four hospitals in Taipei. Participants: Participants (N=176) were patients with TBI (n=88) identified from discharge records of 4 hospitals in Taiwan and family members or friends (n=88) who could answer questions regarding the patient's health and HRQL 1 year after the injury. Interventions: Not applicable. Main Outcome Measures: A health profile of the brief Taiwanese version of the World Health Organization Quality of Life (WHOQOL-BREF) and 2 health utility measures of the time tradeoff (TTO) and standard gamble (SG). Results: Compared with proxy responses, patients provided higher ratings on the domains of the WHOQOL-BREF and lower ratings on the TTO and SG. Intraclass correlation coefficients between patient and proxy ratings varied among the 4 domains of the WHOQOL-BREF, in which levels of agreement were moderate or good for physical capacity (.69) and low for psychological well-being (.45), social relationships (.24), and the environment (.32). Levels of agreement were extremely low for the TTO (0.0) and SG (.10). A profile analysis showed that patients' ratings on the WHOQOL-BREF, on average, were significantly greater than those of their proxies (mean difference, 3.07), with a similar distribution of scatter responses (mean difference, .002) and shape agreement (mean difference, .57). Greater variations in the patient-proxy level of agreement appeared in patients who were younger and had more severe injuries, and also with parent and child proxies. Conclusions: To assess the HRQL of patients with a TBI, the level of patient-proxy agreement was adequate for the physical domain but was lower for the social and environmental domains, and the agreement was very low for the TTO and SG. Furthermore, a patient's age and injury severity, and the patient-proxy' relationship may affect the agreement.