Measures of alpha diversity across patient categories. (A) unadjusted Shannon Index; (B) least squared means of Shannon Index, adjusted for age, sex, race/ethnicity, and antibiotics use one month prior to stool collection (M2); (C) unadjusted number of Observed ESVs; (D) least squared means of number of Observed ESVs, adjusted for age, sex, race/ethnicity, and antibiotics use one month prior to stool collection (M2); Multiple pairwise comparisons had p-value < 0.05, summarized in Supplemental Table 3; HF, heart failure; HT, heart transplant; LVAD, left ventricular assist device.