Differential relationships between self-reported and performance-based health literacy measures and health-related quality of life: A cross-sectional study

Health literacy can be measured using self-reported and performance-based instruments. It remains unclear whether the relationship between health literacy and health outcomes differs between subjective and objective measures. This study examined whether subjective and objective health literacy measures have different relationships with health-related quality of life. This cross-sectional study used data from 5907 participants aged ≥ 19 years in the 2023 Korea National Health and Nutrition Examination Survey. The Korea National Health and Nutrition Examination Survey assesses both self-reported and performance-based health literacy, along with the newly developed health-related quality of life instrument with 8 items (HINT-8). The HINT-8 index was calculated by using a value set developed for the general Korean population. A Tobit regression model was used, with the HINT-8 index as the dependent variable, to account for the ceiling effect. The mean age (± S.E.) of the respondents was 49.5 (±0.4) years. Among them, 60.4% self-reported adequate health literacy and 59.3% answered the performance-based health literacy question correctly. The mean HINT-8 index was 0.818 (± 0.002). There was a moderate association between self-reported and performance-based health literacy measures (φ = 0.271). Adequate self-reported literacy was associated with a 0.027 increase in the HINT-8 index (P < .001). However, performance-based literacy is not significantly associated with this index. Adequate self-reported health literacy was associated with an increase in health-related quality of life, but performance-based health literacy was not. The performance-based measure may not be a critical indictor of health literacy in relation to health outcomes.