TRT-8174

Medication usage is a known contributor to the inter-individual variability of the gut microbiome. However, medications are often used repeatedly and for long periods, a notion yet unaccounted for in microbiome studies. Recently, we and others showed that not only the usage of antibiotics and antidepressants at sampling, but also past consumption, is associated with the gut microbiome. This effect can be “additive”—the more a medication is used, the stronger the impact on the microbiome. Here, by utilizing retrospective medication usage data from the electronic health records and the observational Estonian microbiome cohort shotgun metagenomics data set ( n = 2,509), we systematically evaluate the long-term effects of antibiotics and human-targeted medications on the gut microbiome. We show that past usage of medications is associated with the gut microbiome. For example, the effects of antibiotics, psycholeptics, antidepressants, proton pump inhibitors, and beta-blockers are detectable several years after use. Furthermore, by analyzing a subcohort ( n = 328) with a second microbiome characterization, we show that similar changes in the gut microbiome occur after treatment initiation or discontinuation, possibly indicating causal effects.

This is the first study using detailed retrospective medication usage data from electronic health records to systematically assess the long-term effects of medication usage on the gut microbiome. We identified carryover and additive effects on the gut microbiome for a range of antibiotics and non-antibiotic medications, such as benzodiazepine derivatives, antidepressants and glucocorticoids, among others. These findings highlight a collateral effect of diverse drug classes on the gut microbiome, which warrants accounting for long-term medication usage history when assessing disease-microbiome associations.

Background: Challenges of polypharmacy and the impact of coronavirus disease 2019 (COVID-19) pandemic in older patients require further investigation. This retrospective study analyzed the progression of polypharmacy and anticholinergic burden in older patients in a primary care setting before, during, and after the COVID-19 pandemic.Methods: This 3-year cross-sectional study (2019, 2020, and 2021) comprised a dynamic cohort of individuals aged ≥75 years, who attended the Arrabal Primary Care Center in Zaragoza, Spain. Older patients with polypharmacy (≥5 medications) were identified according to their electronic health records. We collected demographic and clinical data, including medication prescriptions, diagnoses, and anticholinergic risks, and performed descriptive and statistical analyses.Results: This study included a total of 1,928 patients with a mean age of 83.52±0.30 years. Over the 3-year study period, the mean number of medications prescribed increased, from 9.4 in 2019 to 10.4 in 2021. The prevalence of excessive polypharmacy (≥10 medications) increased from 39% in 2019 to 45% in 2021. The most commonly prescribed drugs were anilides, proton pump inhibitors, benzodiazepine derivatives, and platelet aggregation inhibitors. Women had a higher prevalence of illnesses and anticholinergic drug prescriptions than men.Conclusion: The results of this study highlighted an upward trend in polypharmacy and excessive polypharmacy among older patients in primary care settings. Future research should focus on optimizing medication management and deprescribing strategies and minimizing the adverse effects of polypharmacy in this population.