Oral Health and Its Association With Gut Microbiota Diversity in Older Post-Stroke Inpatients.

Oral problems were highly prevalent in older post-stroke inpatients in a convalescent rehabilitation ward.

• Study included 156 older patients after stroke with a mean age of 78.6 years
• Oral problems (ROAG score ≥9) were present in 121 patients (77.6%)
• This was a cross-sectional, registry-based study conducted in a convalescent rehabilitation ward
• Oral health was assessed using the Revised Oral Assessment Guide (ROAG)

Higher (poorer) ROAG scores were significantly associated with lower gut microbiota α-diversity as measured by the Shannon index.

• Multivariable linear regression showed B = -0.044 (95% CI: -0.082 to -0.005) for the association between total ROAG score and Shannon index
• This association was adjusted for confounders including age, sex, stroke type, comorbidities, and nutritional intake
• The Shannon index was the prespecified primary outcome
• Gut microbiota diversity was analyzed by 16S rRNA gene sequencing of fecal samples

No clear associations were found between ROAG scores and the secondary diversity measures of richness or Faith's phylogenetic diversity.

• Association between ROAG score and richness (observed features/OTUs): B = -3.774 (95% CI: -7.844 to 0.296)
• Association between ROAG score and Faith's phylogenetic diversity (PD): B = -0.087 (95% CI: -0.451 to 0.277)
• Both richness and Faith's PD analyses were characterized as exploratory
• The confidence intervals for both secondary measures crossed zero, indicating no statistically significant association

The authors characterized their findings as exploratory and hypothesis-generating due to study design limitations.

• The study had multiple outcomes and no preregistered analysis plan
• The cross-sectional design precludes causal inference
• Authors stated findings require confirmation in independent cohorts and longitudinal studies
• The study was registry-based and cross-sectional in design