Etiology and Outcomes of Patients with Extreme Hyperbilirubinemia in Korea: A Retrospective Cohort Study.

Background/Aim: Extreme hyperbilirubinemia is occasionally observed in intensive care unit (ICU) and non-ICU settings. This study examined the etiologies of extreme hyperbilirubinemia (bilirubin level ≥12 mg/dL) and the factors associated with the 30-day mortality. Methods: This retrospective observational cohort study identified 439 patients with extreme hyperbilirubinemia at the Gyeongsang National University Changwon Hospital between 2016 and 2020. The patients were classified into three groups and 11 diseases according to their etiology. The risk factors associated with 30-day mortality at the baseline were investigated using the Cox proportional hazards model. Results: Of 439 patients with extreme hyperbilirubinemia, 287, 78, and 74 were in the liver cirrhosis/malignancy group, the ischemic injury group, and the benign hepatobiliary-pancreatic etiological group, respectively, with corresponding 30-day mortality rates of 42.9%, 76.9%, and 17.6%. The most common disease leading to hyperbilirubinemia was a pancreatobiliary malignancy (28.7%), followed by liver cirrhosis (17.3%), hepatocellular carcinoma (10.9%), and liver metastases (8.4%). The etiologies of hyperbilirubinemia, obstructive jaundice, infection, albumin level, creatinine level, and prothrombin time-international normalized ratio were independently associated with the 30-day mortality. Conclusions: This study suggests three etiologies of extreme hyperbilirubinemia in the ICU and non-ICU settings. The prognosis of patients with extreme hyperbilirubinemia depends largely on the etiology and the presence of obstructive jaundice.