Altered profiles of fecal metabolites correlate with visceral hypersensitivity and may contribute to symptom severity of diarrhea-predominant irritable bowel syndrome

Figure 2 Correlation of fecal microbial metabolites with irritable bowel syndrome symptom severity scale score or maximum tolerable threshold. A: Correlation of fecal microbial metabolites with irritable bowel syndrome symptom severity scale score in irritable bowel syndrome with predominant diarrhea (IBS-D) patients (R²_Adjusted = 0.693, P < 0.001). The composite index was the sum of score based on linear combination of metabolites using the coefficients listed in Table 4. B: Correlation of metabolites with maximum tolerable threshold in IBS-D patients (R²_Adjusted = 0.255, P = 0.007); The composite index was the sum of scores based on linear combination of isovalerate and valerate using the coefficients listed in Table 6. C: Correlation of metabolites with maximum tolerable threshold in all subjects (R²_Adjusted = 0.079, P = 0.034).