Abstract
Antibiotic use is common among people living with dementia (major neurocognitive disorder) and is associated with seizures and other neuropsychiatric disorders. This population-based cohort study aims to understand the association of repeated antibiotic prescriptions with seizure-related, other neuropsychiatric disorders-related and all-cause hospitalization among people living with dementia, using electronic health records from the Hong Kong Clinical Data Analysis Reporting System. There were 79,367 patients with dementia who were aged 65 or older and had seizure-related high-risk antibiotic prescriptions from 2004 to 2019. There were 71,920 patients with dementia who had other neuropsychiatric disorders-related high-risk antibiotic prescriptions. The seizure-related, other neuropsychiatric disorders-related and all-cause hospitalization risks within 30 days after a high-risk antibiotic prescription in the three highest quartiles of antibiotic use in the past 6 months were compared to the lowest. The increased seizure risks associated with frequent high-risk antibiotic prescribing within 1–30 days are likely due to protopathic bias. In the sensitivity analyses, where the frequency of antibiotic exposure changed from 6 months to 1-year prior and the risks within 15–30 days were examined, no increase in seizure risks was observed. Frequent high-risk antibiotic prescribing did not incur a significantly higher risk of other neuropsychiatric disorders. A progressive increase in risks of all-cause hospitalization was observed with increased high-risk antibiotic prescribing. The findings suggest that clinicians should carefully balance the benefits of repeated antibiotic courses against potential risks when prescribing to people living with dementia.
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Data availability
Data are not available as the data custodians (the Hospital Authority) have not given permission for sharing due to patient confidentiality and privacy concerns. Local academic institutions, government departments, or non-governmental organizations may apply for access to data through the Hospital Authority’s data-sharing portal (https://www3.ha.org.hk/data).
Code availability
The code used for this study is available upon request.
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K.C., J.L., X.Q., and C.C. contributed to the conception of the work. K.C. and C.C. designed the study. K.C. and J.L. contributed to the acquisition and analysis of the data. K.C. drafted the manuscript. E.L. reviewed the ICD-9-CM codes list. All the authors interpreted the data, revised the manuscript critically for important intellectual content and gave final approval of the version to be published. K.C. and J.L. are co–first authors with equal contributions. C.C. provided oversight for all aspects of this project.
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I.C.K.W. reports research funding from the Hong Kong Research Grants Council, the Hong Kong Health and Medical Research Fund, the National Institute for Health Research in England, the European Commission, IQVIA, Amgen and GSK, consulting fees from IQVIA and the World Health Organization, outside of the submitted work. He is a nonexecutive director of Jacobson Medical, Advance Data Analytics for Medical Science (ADAMS) Limited in Hong Kong and OCUS Innovation Limited (HK, Ireland and UK); a former director of Therakind in England and Asia Medicine Regulatory Affairs (AMERA) Services Limited in Hong Kong. C.S.L.C. has received grants from the Food and Health Bureau of the Hong Kong Government, Hong Kong Research Grant Council, Hong Kong Innovation and Technology Commission, Pfizer, IQVIA, and Amgen; personal fees from Primevigilance Ltd., outside the submitted work.
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Chen, K., Lau, J.C.H., Qin, X. et al. Association between repeated antibiotic prescribing and seizure- and other neuropsychiatric disorders-related hospitalization among people living with dementia: a population-based cohort study. npj Aging (2026). https://doi.org/10.1038/s41514-025-00316-y
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DOI: https://doi.org/10.1038/s41514-025-00316-y
