A multi-attribute utility instrument suitable for use in individuals with psychosis – the AQoL-4D: Findings from the Second Australian National Survey of Psychosis

Introduction Multi-attribute utility instruments (MAUIs) are generic health-related quality of life (HRQoL) measures that enable valuation of health states relative to death (0.0) and full health (1.0). The usefulness of MAUIs in people with psychosis has been questioned, with the EQ-5D considered “insensitive”, the 15D “problematic” and the SF-6D “unsuitable”. Objectives Confirm the Assessment of Quality of Life (AQoL)-4D MAUI is useful and meaningful in people with psychosis. Aims Assess utility values across demographic, general and disease-specific health categorisations for a large nationally-representative sample with psychosis ( n  = 1825). Methods Participants underwent a comprehensive 32 module interview encompassing psychopathology to service use. Utility values were calculated by applying a standard algorithm to responses to each of 12 items of the AQoL-4D. Results Utility values were assessed for 1793 participants (98.2%). No ceiling effect was observed and only 6.6% of participants scored in the top decile of HRQoL [0.9–10.0]. In contrast, 10.8% scored in the lowest decile [−0.04–0.10], a floor effect observed in 0.4%. The mean utility value was 0.49 (95% CI: 0.48–0.51), significantly lower than the Australian population norm of 0.81 (95% CI: 0.81–0.82). Greatest impacts on HRQoL were for diminishing global independent functioning as measured by the MSIF (ES MSIF : 0.68–2.24), self-rated current mental health (ES MH : 0.15–1.65) and physical health status (ES PH : 0.11–1.21). Strong effects also observed for course of disorder (ES CoD : 0.08–1.13), current suicidal ideation (ES CSI1 : 0.76–1.08), and labor force participation (ES LFP : 0.11–0.97). Conclusions The AQoL-4D had good lower end sensitivity in a large sample of people with a psychotic illness, and demonstrated responsiveness across subjective, objective and symptom measures.