Mapping the Health of Nation Outcomes Scale (HoNOS) onto the Recovering Quality of Life Utility Index (ReQoL-UI)

Aim: The aim of this project is to develop and assess a mapping function to predict ReQoL-UI (a patient-reported mental health-specific preference-based measure) scores from HoNOS scores (clinician-reported measure, Health of Nation Outcomes Score).

Methods: Participants were recruited from 14 secondary mental health services in England, UK, and their clinician completed HoNoS. Mapping models were estimated using Ordinary Least Squares (OLS) on individual level and mean level data and different model specifications were explored. Model performance was assessed using mean absolute error (MAE), root mean square error (RMSE), percentage of observations with absolute errors greater than 0.1, and plots of the observed and predicted ReQoL-UI utilities and errors.

Results: Matched ReQoL-UI and HoNOS scores were collected for 649 participants. The sample comprised 56% inpatients, with overall mean ReQoL-UI utility of 0.683 and range from 1 to -0.195. Correlations between ReQoL-UI (items and utility) and HoNOS scores were moderate (0.2<r<0.4) or small (<0.2). The best model was OLS estimated using mean level data, with lowest MAE (0.046) and RMSE (0.056).

Discussion: There is little conceptual overlap between ReQoL-UI and HoNOS. They measure different concepts and, arguably, service users and clinicians, who complete the measures respectively, have different perspectives. Under these circumstances, caution is recommended when applying these estimates.