Polypharmacy, hospitalization, and mortality risk: a nationwide cohort study

Tae Ik Chang, Haeyong Park, Dong Wook Kim, Eun Kyung Jeon, Connie M. Rhee, Kamyar Kalantar-Zadeh, Ea Wha Kang, Shin Wook Kang, Seung Hyeok Han

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37 Citations (Scopus)


Polypharmacy is a growing and major public health issue, particularly in the geriatric population. This study aimed to examine the association between polypharmacy and the risk of hospitalization and mortality. We included 3,007,620 elderly individuals aged ≥ 65 years who had at least one routinely-prescribed medication but had no prior hospitalization within a year. The primary exposures of interest were number of daily prescribed medications (1–2, 3–4, 5–6, 7–8, 9–10, and ≥ 11) and presence of polypharmacy (≥ 5 prescription drugs per day). The corresponding comparators were the lowest number of medications (1–2) and absence of polypharmacy. The study outcomes were hospitalization and all-cause death. The median age of participants was 72 years and 39.5% were men. Approximately, 46.6% of participants experienced polypharmacy. Over a median follow-up of 5.0 years, 2,028,062 (67.4%) hospitalizations and 459,076 (15.3%) all-cause deaths were observed. An incrementally higher number of daily prescribed medications was found to be associated with increasingly higher risk for hospitalization and mortality. These associations were consistent across subgroups of age, sex, residential area, and comorbidities. Furthermore, polypharmacy was associated with greater risk of hospitalization and death: adjusted HRs (95% CIs) were 1.18 (1.18–1.19) and 1.25 (1.24–1.25) in the overall and 1.16 (1.16–1.17) and 1.25 (1.24–1.25) in the matched cohorts, respectively. Hence, polypharmacy was associated with a higher risk of hospitalization and all-cause death among elderly individuals.

Original languageEnglish
Article number18964
JournalScientific reports
Issue number1
Publication statusPublished - 2020 Dec 1

Bibliographical note

Funding Information:
The authors would like to thank the Korean National Health Insurance Service for providing access to their data (database no. NHIS-2019-1-436). This work was supported by a Grant (NHIMC 2019-06-014) funded by the National Health Insurance Service Medical Center, Ilsan Hospital. The funding source had no role in study design, data collection, data analysis, decision to publish, or preparation of the manuscript. KKZ was supported by NIH (NIDDK) Grants K24-DK091419, U01-DK102163 and philanthropic grants from Mr. Harold Simmons, Mr. Louis Change, Joseph Lee, and AVEO, Inc. CMR was supported by NIH (NIDDK) Grants K23-DK102903 and R03-DK114642.

Publisher Copyright:
© 2020, The Author(s).

All Science Journal Classification (ASJC) codes

  • General


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