Continuity of care (COC) has received attention over the past decade. COC has also become increasingly important for hospital managers and policy makers because of competitive health care market conditions. The purpose of this study was to assess the association between hospital charges and patients' continuity of care-assessed by three indices of continuity of care—among outpatients with hypertension in South Korea.

This study used the National Health Insurance Service–Cohort Sample Database from 2002 to 2013. A total of 247,125 participants were analyzed at baseline (2002); continuity of care was defined using the continuity of care index, the Herfindahl–Hirschman index (a new continuity of care index), and the “most frequent provider continuity” index. Primary analyses were based on the generalized estimating equation regression model, which accounts for correlation among individuals within each hospital.

After adjustment for age, sex, residential region, patient clinical complexity level, diagnosed code, hospital type, organization type, number of beds, number of doctors, and year, there was a negative correlation between hospital charges and continuity of care index (β=−0.163, P<0.0001), the Herfindahl–Hirschman index (β=−0.105, P<0.0001), and the “most frequent provider continuity” index (β=−0.131, P<0.0001). Subgroup analyses based on hospital type produced similar trends.

For all indices studied, hospital charges declined gradually with increasing continuity of care. Our study suggests that long-term, trusting partnerships between patients and physicians reduce hospital costs.