Effects of the type and quality of usual source of care on medical expenditures in adults with diabetes before and during the COVID‑19 pandemic: a panel data analysis using the Korea Health Panel (2019-2022).

backgroundSouth Korea experiences the highest diabetes-related hospitalization rates among OECD countries. Although integrated primary care could potentially lower preventable hospitalizations and healthcare costs, the limited uptake of a usual source of care (USC) and underdeveloped primary care services in Korea have impeded progress, and the role and functions of primary care remain insufficiently defined.

methodsThis study investigated how having a USC affects medical expenditures in adults with diabetes by using Korea Health Panel data from 2019 to 2022, spanning the pre-pandemic (2019) and pandemic (2020-2022) periods. The analysis included 6,144 individuals. The main independent variable was the type and quality of USC, categorized into three groups: no USC, place-only USC, and physician-based USC. Quality was assessed by patient-reported comprehensiveness and coordination, combined into an integrated quality index. We applied panel regression analysis using the Hausman-Taylor estimation technique to address both time-varying and time-invariant covariates while mitigating endogeneity concerns.

resultsBetween 2019 and 2022, the proportion of individuals with a physician at a regular location serving as their USC increased from 58.5% to 66.1%, while the proportion without a physician as their USC decreased from 15.1% to 10.9%, with larger variation among vulnerable populations. The physician-based USC group consistently incurred higher absolute expenditures but showed the smallest relative increase during the pandemic, compared with sharp rises in the no-USC and place-only USC groups. Adults with diabetes whose USC was a high-quality primary care physician-defined by favorable patient ratings of comprehensiveness and coordination-were associated with approximately 13.1% lower healthcare expenditures compared to those lacking a physician as their USC (β = - 0.140, P = 0.006). Moreover, community clinic-based physicians as USC were associated with lower expenditures, while hospital-based USC was associated with higher costs, though not statistically significant.

conclusionThese findings underscore the importance of increasing access to high-quality primary care physicians as USC to optimize chronic disease management and maintain sustainable healthcare systems.