Evaluating the Healthcare Burden and Clinical Impact of Polypharmacy Among the Elderly in South Korea

OBJECTIVES: This study was to investigate the effects of polypharmacy on medical use, medical costs, and clinical outcomes of the elderly in South Korea.

METHODS: This study involved individuals aged 65 years or older who participated in a national survey (KNHANES) from 2012 to 2016, and we combined it with claims data (N= 3,297). Polypharmacy is defined as taking five or more drugs for more than 30 days in 180 days and outcomes from one-year follow-up after polypharmacy. We performed multivariable linear regression to examine the effect of polypharmacy on medical costs including outpatient, drug, and per capita mean of total costs, and a two-part model was used on the inpatient costs. In addition, we performed multivariate logistic regression to measure the association between polypharmacy and hospitalization/mortality.

RESULTS: Multivariable linear regression indicated that the polypharmacy group had significantly higher one-year total medical costs of ₩954,193, with increases of ₩363,865 in outpatient and ₩553,739 in drug costs compared to the non-polypharmacy group. Elderly with polypharmacy were 46.1% more likely to require hospitalization, with their average inpatient costs being ₩1,318,828 higher than those without polypharmacy (p < 0.05). The inpatient costs adjusting the probability of hospitalization showed that the total mean cost of hospitalization in one year increased by ₩607,980 for elderly patients with polypharmacy compared to no-polypharmacy. Compared with participants without polypharmacy, those with polypharmacy showed a higher risk of hospitalization (OR:1.59, 95% CI:1.33-1.89) and mortality (OR:4.16, 95% CI:1.58-10.96).

CONCLUSIONS: This study demonstrates that polypharmacy significantly increases the financial burden on healthcare systems due to higher medical costs. Additionally, polypharmacy is associated with a higher risk of hospitalization and mortality among the elderly. These findings suggest the need for careful medication management and monitoring in older adults to mitigate the adverse effects of polypharmacy and to optimize clinical outcomes.