Travel Time to Healthcare and Type 2 Diabetes Mellitus Management in Korea: A Nationwide Retrospective Study

This study aimed to investigate the relationship between average travel time to healthcare facilities and management of type 2 diabetes mellitus (T2DM). In addition, we examined how average travel time and the presence of a usual source of care (USC) interact to influence T2DM management.

We analyzed National Health Insurance data from 2015 to 2019 for a cohort of 81,588 patients newly diagnosed with T2DM in 2014. Geographic Information System-based road network data were used to calculate travel time. Outcome variables for T2DM management included regular visits, medication adherence, and monitoring tests: hemoglobin testing, lipid panel testing, and fundus examination. Generalized Estimating Equations models were used to assess the effects of travel time on T2DM management.

Patients traveling ≤ 15 minutes to their healthcare facilities had higher rates of regular visits (risk ratio [RR], 1.04; 95% confidence interval [CI], 1.03-1.05), but showed no significant difference in medication adherence (RR, 1.00; 95% CI, 1.00-1.01) relative to patients with longer travel times. The presence of a USC was associated with higher levels of medication adherence (RR, 1.16; 95% CI, 1.15-1.16) and regular visits (RR, 1.38; 95% CI, 1.37-1.40). Patients with both a USC and short travel time had the highest medication adherence and visit rates (RR, 1.14 and 1.42) compared to those without a USC and with longer travel times, reflecting significant interaction effects. Shorter travel time was, however, associated with lower uptake of diabetes monitoring tests. Patients who most frequently visited tertiary or general hospitals had lower regularity of visits and medication adherence but higher rates of diabetes monitoring tests.

This study highlights the importance of the combined effect of travel time and the presence of a USC in promoting regular visits to healthcare facilities among T2DM patients, rather than the effect of either factor alone. These findings underscore the need to consider both proximity and continuity of care when planning healthcare access strategies for T2DM management. In addition, measures are needed to promote the implementation of diabetes monitoring tests in clinics.