Using Linear Equating to Map PROMIS^® Global Health Items and the PROMIS-29 V2.0 Profile Measure to the Health Utilities Index Mark 3

Background: Preference-based health-related quality of life (HR-QOL) scores are useful as outcome measures in clinical studies, for monitoring the health of populations, and for estimating quality-adjusted life-years. Methods: This was a secondary analysis of data collected in an internet survey as part of the Patient-Reported Outcomes Measurement Information System (PROMIS^®) project. To estimate Health Utilities Index Mark 3 (HUI-3) preference scores, we used the ten PROMIS^® global health items, the PROMIS-29 V2.0 single pain intensity item and seven multi-item scales (physical functioning, fatigue, pain interference, depressive symptoms, anxiety, ability to participate in social roles and activities, sleep disturbance), and the PROMIS-29 V2.0 items. Linear regression analyses were used to identify significant predictors, followed by simple linear equating to avoid regression to the mean. Results: The regression models explained 48 % (global health items), 61 % (PROMIS-29 V2.0 scales), and 64 % (PROMIS-29 V2.0 items) of the variance in the HUI-3 preference score. Linear equated scores were similar to observed scores, although differences tended to be larger for older study participants. Conclusions: HUI-3 preference scores can be estimated from the PROMIS^® global health items or PROMIS-29 V2.0. The estimated HUI-3 scores from the PROMIS^® health measures can be used for economic applications and as a measure of overall HR-QOL in research.