Jaundice marks immunoglobulin G4-related cholangitis in type 1 autoimmune pancreatitis patients

Background: The phenotype of immunoglobulin G4 (IgG4)-related cholangitis (IRC) patients among type 1 autoimmune pancreatitis (AIP-1) patients in Taiwan, where secondary biliary cholangitis is prevalent, is unknown. Objectives: To evaluate the phenotype of IRC in AIP-1 patients. Design: Retrospective cohort study. Methods: A 15-year cohort study of 237 AIP-1 patients was conducted. AIP-1 was diagnosed according to the HISORt criteria. Results: Of 237 AIP-1 patients, 90 (37.9%) had IRC (males: n = 80 (88.9%); type 1 IRC: n = 80 (88.8%); mean age: 65.63 years). Among AIP-1 patients, those with IRC had higher alanine aminotransferase (ALT) (179.4 ± 202.6 vs 118.0 ± 167.8 U/L, p = 0.014), alkaline phosphatase (ALP) (322.5 ± 239.1 vs 201.4 ± 193.7 U/L, p < 0.001), total bilirubin (bili-T) (5.69 ± 5.28 vs 2.95 ± 4.19 mg/dL, p < 0.001), and IgG4 (1271.9 ± 1256.3 vs 904.0 ± 811.4 mg/dL, p = 0.015) levels and a borderline higher cumulative incidence of mortality (14.4 vs 7.5%, p = 0.068) than those without IRC did. Moreover, baseline bili-T levels (odds ratio (OR): 1.194, p = 0.031) (cutoff: >2.2 mg/dL) were independently associated with IRC. Among AIP-1 patients, baseline ALP (OR: 1.004, p = 0.001), fibrosis-4 index (OR: 1.156, p = 0.025), cirrhosis (OR: 23.157, p < 0.001), and neutrophil-to-lymphocyte ratio (NLR) (OR: 1.103, p = 0.008) were associated with mortality. Among the IRC-AIP-1 patients, baseline ALP levels (OR: 1.002, p = 0.028) and NLR (OR: 1.091, p = 0.012) were associated with mortality. Conclusion: In total, 37.9% of AIP-1 patients had IRC. Higher levels of hepatocellular injury, cholestatic features, and IgG4 were noted in patients with IRC than in patients without IRC. Baseline bili-T level (cutoff > 2.2 mg/dL) is an indicator of IRC among AIP-1 patients. Biliary injury and systemic inflammation are associated with mortality in all AIP-1 and IRC-AIP-1 patients. Liver fibrosis subsequent to IRC might further increase mortality in AIP-1 patients.