Impact of Residential Area on Antihypertensive Medication Adhrence in Seoul, Korea

Abstract

Background: This study aimed to investigate the relationship between residential area and antihypertensive medication adherence in Seoul, the representative metropolis of Korea. Methods: We obtained data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) of Korea covering the years 2008-2013.NHIS-NSC curates a random data sample comprising 2.2% (N=1,048,061) of the whole population (N=46,605,433). The subject pool consisted of 35,478 residents of Seoul over 20 years of age, who had been on an antihypertensive medication for at least one year. Medication adherence was assessed using the medication possession ratio (MPR). We divided subjects by administrative district (Gu) within Seoul, and analyzed proportions of adherent patients. Results: Among administrative districts in Seoul, the proportion of adherent patients (MPR >80%) was highest in Gangdong-gu (71.8%), with Seongdong-gu (71.7%), Songpa-gu (71.4%), and Jung-gu (70.9%) closely following. The proportion of adherent patients was lowest in Gwanak-gu (65.4%), and Jongro-gu (65.5%), with Geumcheon-gu (65.7%) slightly higher. Trends in proportion of adherent patients among districts remained similar after adjustments were made for confounding factors at the individual level. Trends also remained similar after adjusting for confounding factors at the local level. Conclusion:Health system factors such as distribution and accessibility of medical institutions by administrative districts exerted relatively little influence on antihypertensive medication adherence in Seoul.

Multilevel Analysis of the Relationship Between Prescribing Institutions and Medication Adherence Among Patients With Hypertension and Diabetes in Korea

“…Regional-level factors have also been evaluated to ascertain significant differences in regional adherence rates, after adjusting for both individual and regional level factors. These factors include the number of hospital beds, total hospitals, tertiary hospitals, general hospitals, clinics, and pharmacies, as well as regional gross domestic product [16].…”