OBJECTIVES: Health-related quality-of-life (HRQoL) in Japanese patients with cognitive impairment associated with schizophrenia (CIAS) have not been investigated. This study aims to assess HRQoL in Japanese CIAS patients using the Health Utilities Index Mark 3 (HUI3) and the EQ-5D-5L, a general patient-reported outcome measure.

METHODS: This study utilizes blinded baseline data of the Japanese subgroup in the Phase III randomized placebo-controlled trials of CONNEX-1 and CONNEX-2, which investigate the efficacy, safety, and tolerability of Iclepertin in adult patients with schizophrenia currently stable with antipsychotic treatment. Baseline scores prior to study drug administration were used to calculate descriptive statistics of each QOL measure (multi- and single-attribute utility values of Japanese HUI3 and EQ-5D-5L utility value). Each score was calculated using the Japanese value set and the Japanese utility function.

RESULTS: By December 2023, total of 149 Japanese adults with mean age of 37.2 years old who had schizophrenia were enrolled in the cohort. Among them, the HUI3 and the EQ-5D-5L utility value were obtained from 121, 129 subjects, respectively. Median (with 25 and 75 percentiles) of the HUI3 multi-attribute utility value and the EQ-5D-5L utility value was 0.63 (0.45, 0.82) and 0.85 (0.77, 0.89) respectively. The cognition utility value marked the lowest (0.58 [0.58, 0.83]) among the HUI3 single-attribute utility values. The HUI3 multi-attribute utility values were lower and had smaller ceiling effects than the EQ-5D-5L index utility values.

CONCLUSIONS: This study is the first study to evaluate the QoL scores of Japanese patients with CIAS. HUI3 could contribute to appropriate assessment of QoL scores in Japanese patient with CIAS, as a cognitive attribute of HUI3 was demonstrated to be able to capture the effects of cognitive function.