BACKGROUND: The impact of diabetes mellitus (DM) on the natural progression of primary biliary cholangitis (PBC) has not yet been determined. The objective of this study was to determine whether DM is associated with increased liver damage in PBC.

MATERIAL AND METHODS: There were 168 treatment-naïve PBC patients, including 37 patients with DM, enrolled in this study between 2012 and 2018. Patient demographics, clinical features, and biochemical and histopathological parameters were collected. Disease severity was assessed by pathological data, Child Pugh grade, and noninvasive indicators. Relevant risks for PBC-related cirrhosis were assessed by univariate and multivariate analyses.

RESULTS: The noninvasive scores predicting fibrosis were all significantly higher in PBC-DM versus PBC-only patients (fibrosis-4 score: 4.08 versus 3.21, P=0.029; aminotransferase-to-platelet ratio index: 1.46 versus 1.09, P=0.036; red blood cell distribution width to platelet ratio: 0.12 versus 0.08, P=0.016; Mayo Risk Score: 1.52 versus 0.19, P=0.011; the Newcastle model: 2.85 versus 2.07, P=0.009; albumin-bilirubin score: –1.92 versus –2.10, P=0.023). Cirrhosis occurred at a higher rate (62.2% versus 42.0%, P=0.030) in PBC-DM patients, but Child Pugh grade and pathological differences could not be accurately determined. A multivariate analysis revealed DM increased the risk of PBC-related cirrhosis, with a resulting adjusted odds ratio of 2.351 (95% confidence interval, 1.022–5.409).

CONCLUSIONS: The results of this retrospective, single-center study suggest that DM is associated with more severe liver fibrosis in PBC. Consequently, improved management of DM might alter the prognosis of PBC patients.

Keywords: Cholangitis, Diabetes Mellitus, Liver Cirrhosis, bilirubin, Diabetes Complications, Disease Progression, Erythrocyte Indices, Liver, Liver Cirrhosis, Biliary, Multivariate Analysis, Severity of Illness Index