Distribution of Prescriptions From Medical Institutions to Pharmacies in Japan: An Analysis of Health Insurance Claims Database

OBJECTIVES: In Japan, the healthcare insurance system allows patients unrestricted access to medical institutions and prescription pharmacies. This system has led to the concentration of pharmacies near medical institutions. This study aimed to describe the pattern of patient visits to medical institutions and pharmacies, and to quantify the distribution of prescriptions.

METHODS: We conducted a retrospective observational study using health insurance claim data from a Japanese prefecture. We analyzed prescriptions made in one year, identifying the medical institutions that issued the prescriptions and pharmacies that dispensed the medicines. We calculated the correlation coefficient between the number of medical institutions and number of pharmacies visited by each patient during the year. Additionally, we calculated the Gini coefficient and Herfindahl-Hirschman Index for each medical institution to quantify the concentration of prescriptions to pharmacies. For institutions with available address data, we calculated the proportion of medicines dispensed from pharmacies in the same block and from those within a 100-meter distance.

RESULTS: We analyzed approximately 4.32 million prescriptions from 1,116 medical institutions and 823 pharmacies for 410 thousand individuals. The patient-level correlation coefficient between the number of medical institutions and pharmacies was 0.918. The median Gini coefficient and Herfindahl-Hirschman Index for medical institutions were 0.80 (interquartile range, 0.42-0.92) and 9,000 (4,850-9,747), respectively. In the analysis of 3.65 million prescription from 887 medical institutions with address data, 49% and 60% of the medicines were dispensed in the same block and within 100 m, respectively.

CONCLUSIONS: The number of pharmacies visited by patients increased in accordance with the number of medical institutions. Pharmacies located near medical institutions held a near-monopoly on prescriptions. These findings provide a baseline for discussions on the future roles and functions of pharmacies.