OBJECTIVES: To explore the effects of age and gender on mapped EQ-5D-5L utilities derived using algorithms developed by the National Institute for Health and Care Excellence Decision Support Unit (DSU) and EuroQol Group.

METHODS: Analyses employed data from eight randomized controlled trials of nivolumab in which the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 and EQ-5D-3L were administered. Mapped EQ-5D-5L utilities were generated using the English value set and input into models submitted for NICE appraisals to generate QALYs. Descriptive statistics were produced for the pooled trial data set as well as age and gender subgroups. Bootstrapping was employed to generate simulated samples with skewed distributions of age and gender to assess impacts on utilities and QALYs. Additional analyses assessed EQ-5D-3L differential item functioning (DIF) attributable to age and gender.

RESULTS: Across utility indices, mean scores were higher for males than females and inversely related to age. The EuroQol mapping algorithm yielded higher mean scores than the DSU algorithm for all age and gender subgroups. In resampling analyses, mean scores were lower for all indices in simulated samples with a skew toward female gender. At baseline, mean differences in mapped EQ-5D-5L utility index scores (original sample minus simulated sample with highest female gender skew) were 0.017 and 0.016, respectively, for the EuroQol algorithm including or excluding age and gender and 0.018 and 0.019, respectively, for the DSU algorithm with residuals specified as Gaussian or copula-mixture. Meaningful DIF was observed for the EQ-5D-3L anxiety/depression item with respect to age and usual activities item with respect to gender. Results of QALY analyses will be presented at the meeting.

CONCLUSIONS: Differences between the two mapped EQ-5D-5L indices were slight with the DSU index being more sensitive to sample demographic characteristics. The implications of this for economic modeling are to be discussed.