Primary sclerosing cholangitis (PSC) is a rare disease but is increasingly reported in China (mainly in the Chinese language). However, most of the PSC literatures reported from China are case reports, small case series, and review articles. Up to now, there is no information on the epidemiology and disease burden of PSC in China. This study would use EMR/HIS and research databases to investigate the epidemiology, cascade, and treatment pattern of PSC in China.

Identify the PSC cases diagnosed from the earliest date available to the present in the SuValue Research Database and the HIS/EMR from clinical sites through diagnostic ICD codes, laboratory, pathology, imaging, endoscopy, surgery, medication, hospitalization, and health outcomes.

Collect information on PSC cases' key demographic, the time of PSC diagnosis, hematological/biochemical variables (ALT, AST, ALP, GGT, ALP TBil, ALB), MRCP or ERCP or pathological report, IBD (UC or CD) symptoms, or colon, medication information, clinical outcomes (including cirrhosis, decompensated cirrhosis, death or liver transplantation) as well as current or past treatment.

Inclusion Criteria:

1. Retrospectively review PSC cases before April 1, 2002 will be identified by diagnostic codes from the International Classification of Diseases (ICD)-9, and for those after April 1, 2002, we used ICD-10.
2. We identified patients using an electronic search of SuValue Research Database and HIS of BFH-CMU and BYH-CMU using PSC related ICD codes (ICD-9: 576.1; ICD-10: K83.016/K83.016(China version)). To supplement the ICD search, an electronic keyword search for "primary sclerosing cholangitis" or "seclerosing cholangitis" was conducted on all radiology, endoscopy, pathology reports beginning on earliest date available in the database of SuValue Research Database and HIS of BFH-CMU and BYH-CMU. We reviewed the medical charts of identified patients and diagnostic criteria including cholestatic biochemistry (ALP, GGT elevations), and typical imaging (MRCP or ERCP) or pathological features, excluding other known etiology. For patients with multiple visits for PSC, we reviewed only the index visit. To ensure consistency, chart review was independently assessed by two hepatologists. Discrepancies in compliance were resolved by discussion between the two main reviewers. Any unresolved discrepancies were decided by a third expert hepatologist.

Exclusion Criteria:

1. The cases with secondary sclerosing cholangitis caused by cholelithiasis, IgG4 related disease, malignancy or other known etiologies.
2. The cases with missing key results on clinical, biochemical (ALP, GGT, bilirubin), radiological (MRCP or ERCP) or histological investigations.

Total number of subjects expected to be reviewed is 800. The subjects in this study will consist of two parts: identify PSC cases by retrospective review of an inter-regional database and retro-prospective review of EMR of two tertiary medical centers in Beijing.