A study of the correlation between serum bile acid profile and prognosis in patients with sepsis

Sepsis remains a major global health challenge, with high mortality associated with multi-organ dysfunction, faster identification and assessment of sepsis is beneficial to guide treatment. Studies have found changes in the composition of bile acids (BAs) in the serum and stool of patients with sepsis compared to healthy individuals, so we sought to explore changes in serum BAs in patients with sepsis and their correlation with prognosis.

This prospective study enrolled healthy individuals and sepsis patients admitted to the Intensive Care Unit of the Second Affiliated Hospital of Nanjing Medical University between January 2023 and January 2024. Clinical data were collected, and serum levels of 15 BAs were quantified using liquid chromatography-tandem mass spectrometry. Patients were categorized into groups based on 28-day outcomes, severity of illness, and infection source for subsequent analysis.

Compared with healthy individuals, the secondary BAs in sepsis patients were significantly lower, among which ursodeoxycholic acid (UDCA) is below the reference range. Compared with the survivors, the taurocholic acid (TCA) and taurodeoxycholic acid (TDCA) of the non-survivors of sepsis were significantly increased, while the UDCA was further decreased. Patients with pulmonary infection exhibited higher overall BA levels than those with abdominal infection. Both TCA and TDCA correlated positively with bilirubin, while UDCA correlated negatively with SOFA scores, C-reactive protein, and procalcitonin. In univariate COX regression, UDCA was associated with 28-day mortality (HR =0.990, P=0.042). ROC analysis showed that the area under the curve for UDCA predicting 28-day mortality was 0.643 (P=0.034).

Secondary BAs were significantly reduced in sepsis patients, with UDCA showing the most pronounced decrease. This reduction becomes even more substantial in non-survivors. The overall BA levels were significantly higher in patients with pulmonary infection than in those with abdominal infection. UDCA was negatively correlated with SOFA score, CRP, and PCT in sepsis patients, and combining it with other indicators improves the prediction of sepsis prognosis. These results indicate that UDCA may exert a protective effect in sepsis.