Validation of the health-related quality of life instrument with 8 items for assessing health-related quality of life in patients with oropharyngeal cancer: a comparison with the EQ-5D-5L.

BACKGROUND: To overcome the limitations of existing health-related quality of life (HRQoL) instruments, the HRQoL Instrument with 8 Items (HINT-8) was developed for the Korean population. We aimed to evaluate the validity, interrater reliability, and agreement of the HINT-8 compared to the EQ-5D-5 L among patients with oropharyngeal cancer (OPC). METHODS: A total of 327 patients with OPC aged ≥ 19 years who received treatment at 14 hospitals in South Korea were recruited between August 2023 and February 2024. HRQoL was assessed using the two instruments. The psychometric evaluation included analyses of validity (convergent and known-group validity), agreement (intraclass correlation coefficient and Bland-Altman analysis), and reliability (internal consistency measured by Cronbach's alpha). The ceiling effects and score distributions were also examined. RESULTS: In total, 299 respondents were included in the final analysis. Both instruments demonstrated high internal consistency (HINT-8: α = 0.872; EQ-5D-5 L: α = 0.845) and good agreement (intraclass correlation coefficient [ICC] = 0.80; 95% confidence interval [CI]: 0.76-0.84). The convergent validity was supported by strong correlations between the HINT-8 index and both the EQ-5D-5 L index (r = 0.805) and EQ VAS (r = 0.715). The ceiling effect of HINT-8 (12.7%) was substantially lower than the EQ-5D-5 L (32.8%). CONCLUSIONS: The HINT-8 is a valid, reliable, and responsive instrument for measuring HRQoL in patients with oropharyngeal cancer. These findings suggest that HINT-8 can serve as a valuable complementary instrument to the EQ-5D-5 L.