Polypharmacy is associated with altered gut microbiota diversity in older post-stroke inpatients

Gut microbiota diversity plays a crucial role in various health outcomes, including metabolic regulation and nutritional status. Polypharmacy, common among older adults, has been linked to adverse clinical outcomes, yet its impact on gut microbiota diversity remains poorly understood. This study aimed to investigate the association between polypharmacy and gut microbiota diversity in older post-stroke patients.

This cross-sectional study included post-stroke inpatients aged 65 years or older undergoing rehabilitation. Polypharmacy was defined as the prescription of five or more drugs. Metagenomic analysis of DNA from patient fecal samples was conducted, calculating three alpha diversity indices: the Shannon Diversity Index, Operational Taxonomic Unit (OTU) richness, and Faith's Phylogenetic Diversity (PD). Multiple linear regression analysis was used to determine whether polypharmacy was independently associated with the gut microbiota diversity upon admission, adjusting for potential confounders.

A total of 156 patients (mean age 78.4 years; 55.8 % male) were analyzed. The median number of medications taken on admission was 6 (4-8), and 69.9 % of patients had polypharmacy. Polypharmacy was independently associated with decreased Shannon Diversity Index (β = -0.202, p = 0.019). No statistically significant association was found with Observed OTUs (β = -0.159, p = 0.067) and Faith's PD (β = -0.38, p = 0.111).

Polypharmacy is associated with qualitative alterations in the gut microbiota of older post-stroke patients, with a potential negative trend in quantitative alterations and phylogenetic classification. The findings underscore the need to consider the impact of polypharmacy on the gut microbiome in stroke management.