Abstract

In modern society, the growing burden of chronic diseases and mental health problems highlights the importance of prevention and continuous care. A usual source of care (USOC) is increasingly recognized as a key component in delivering primary care services. Using data from the 2019–2021 Korea Health Panel Survey, this study longitudinally analyzed the impact of having a USOC on health-related quality of life (HRQoL). The analysis focused on adults aged 19 or older whose USOC status remained consistent over three years, applying a random effects panel regression model. The results showed no statistically significant association between USOC and HRQoL. This finding may reflect that, because HRQoL as a comprehensive outcome measure is inherently less sensitive to short-term changes or single factors, a three-year observation period may not have been sufficient to capture meaningful changes. This result may also be partly explained by unobserved factors, such as health conditions and health care utilization patterns, as well as by institutional or structural contexts. Therefore, the results suggest that the effect of USOC may not be readily detectable in HRQoL, a complex outcome measure, rather than indicating an absence of effect. Future efforts should focus on strengthening the qualitative functions of USOC, establishing the necessary institutional foundations, and providing tailored support for vulnerable populations such as older adults and persons with disabilities. To support this policy direction, long-term and in-depth research is needed to more precisely elucidate the relationship between USOC and HRQoL.