2.5. Statistical Analysis
TYPE 2 DIABETES
The number of study participants was calculated based on 80% power (at α = 0.05), to conservatively detect a 25% difference in the Firmicutes/Bacteroidetes ratio between the two groups, which was based on previous studies showing increased Bacteroidetes and decreased Firmicutes in subjects with type 2 diabetes after DPP-4 inhibitor treatment [For microbiota, rarified counts were used for analysis including α-diversity (richness and Shannon index) (GUniFrac and vegan R packages). Taxa were selected for analysis if they were present in at least 25% of the samples and had a mean relative abundance greater than 0.01%, to exclude unnecessary comparisons. The gut microbial overall structure between groups was visualized by principal coordinates analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA) using Bray–Curtis dissimilarities at the genus level for (i) the intention-to-treat population; (ii) those who reached the HbA1c target of ≤7.0% (53 mmol/mol); and (iii) those who did or did not gain body weight. To identify clinically relevant genera, a linear discrimination analysis (LDA) with adjustment for visit date (