The association between gut microbiota and postoperative delirium in patients

Abstract

Postoperative delirium is a common postoperative complication in older patients, and its pathogenesis and biomarkers remain largely undetermined. The gut microbiota has been shown to regulate brain function, and therefore, it is vital to explore the association between gut microbiota and postoperative delirium. Of 220 patients (65 years old or older) who had a knee replacement, hip replacement, or laminectomy under general or spinal anesthesia, 86 participants were included in the data analysis. The incidence (primary outcome) and severity of postoperative delirium were assessed for two days. Fecal swabs were collected from participants immediately after surgery. The 16S rRNA gene sequencing was used to assess gut microbiota. Principal component analyses along with a literature review were used to identify plausible gut microbiota, and three gut bacteria were further studied for their associations with postoperative delirium. Of the 86 participants [age 71.0 (69.0-76.0, 25-75% percentile of quartile), 53% female], 10 (12%) developed postoperative delirium. Postoperative gut bacteria Parabacteroides distasonis was associated with postoperative delirium after adjusting for age and sex (Odds Ratio [OR] 2.13, 95% Confidence Interval (CI): 1.09-4.17, P = 0.026). The association between delirium and both Prevotella (OR: 0.59, 95% CI: 0.33-1.04, P = 0.067) and Collinsella (OR: 0.57, 95% CI: 0.27-1.24, P = 0.158) did not meet statistical significance. These findings suggest that there may be an association between postoperative gut microbiota, specifically Parabacteroides distasonis, and postoperative delirium. However, further research is needed to confirm these findings and better understand the gut-brain axis's role in postoperative outcomes.

Fig. 1. Flow diagram.

The flow diagram shows that 491 participants were screened for the studies, and 220 were initially enrolled. One hundred seventeen participants were excluded after enrollment, and 103 were included in the gut microbiota cohort. During the analysis, 17 additional participants were excluded, resulting in 86 participants for the final data analysis.

Fig. 2. Different postoperative gut bacteria between participants with and without postoperative delirium.

Participants who developed postoperative delirium (N = 10) had a higher postoperative relative abundance of gut bacteria of Parabacteroides distasonis (A) a lower abundance of postoperative gut bacteria of Prevotella (B) but not Collinsella (C) than the participants who did not develop postoperative delirium (N = 76). The box indicates the median (50th percentile), the first quartile (25th percentile), and the third quartile (75th percentile) of the abundance of bacteria. Mann–Whitney U test was used to determine the differences in bacteria abundance between the participants with postoperative delirium and those without postoperative delirium.