Association between novel inflammatory markers and severity of acute cholangitis: a retrospective cohort study.

BACKGROUND: Accurate assessment of the severity of acute cholangitis (AC) is crucial for guiding timely and appropriate interventions. METHODS: In this retrospective cohort study, 1,647 patients with confirmed AC who were admitted to a single tertiary center between January 2014 and December 2023 were included. The patients were classified as mild (n = 1,075), moderate (n = 366), or severe (n = 206) on the basis of the Tokyo Guidelines 2018. Baseline values of the neutrophil percentage-to-albumin ratio (NPAR), blood urea nitrogen-to-albumin ratio, red blood cell distribution width-to-albumin ratio, and neutrophil-to-lymphocyte ratio were collected at admission. RESULTS: All four markers were significantly higher in patients with more severe AC than in those with mild or moderate AC (p < 0.001 for all comparisons). The NPAR was significantly higher in patients with moderate or severe AC than in those with mild AC, with similar values in the moderate and severe groups (2.186 [mild], 2.876 [moderate], and 2.846 [severe]). The NPAR showed the highest area under the curve values, with 0.793 (95% CI, 0.770-0.815) for the mild vs. moderate-to-severe, 0.727 (95% CI, 0.693-0.762) for the mild-to-moderate vs. severe, and 0.815 (95% CI, 0.778-0.852) for the shock vs. non-shock groups. The optimal NPAR cut-off values were 2.513, 2.714, and 2.663, respectively. A restricted cubic spline analysis showed a significant overall association between these markers and the severity of AC (p < 0.001). CONCLUSION: The NPAR shows superior prognostic performance to the blood urea nitrogen-to-albumin ratio, red blood cell distribution width-to-albumin ratio, and neutrophil-to-lymphocyte ratio in predicting the severity of AC.