Abstract
Background and aims: Primary sclerosing cholangitis (PSC) is an immune-mediated chronic liver disease characterised by inflammation and fibrosis of intrahepatic and extrahepatic bile ducts leading to cirrhosis and its complications. Previous epidemiological studies have shown that the incidence and prevalence of PSC in Canterbury, New Zealand, are among the highest reported worldwide (1)(2). A nationwide population census was conducted in New Zealand in 2023. Therefore, we aimed to report the latest epidemiology of PSC in Canterbury based on the Census 2023 population data.
Method: Patients with a diagnosis of PSC were added to our existing database. Radiology and histopathology reports were also searched to ensure all PSC cases were captured. Those with radiological or histological diagnoses of sclerosing cholangitis without other identifiable causes were included. Incidence and prevalence rates were calculated using Census population data from Statistics New Zealand.
Results: Our database included 142 PSC patients as of 31st December 2023. From 2017 to 2023, 35 new PSC cases were diagnosed in Canterbury. The average annual incidence of PSC for this period was 0.77/100,000 (95% CI 0.10–1.45/100,000). Excluding patients who had moved away from the region and deceased, there were 82 prevalent cases in 2023. The point prevalence of PSC in Canterbury on 31st December 2023 was 12.6/100,000 (95% CI 9.87–15.32/100,000). Ethnicity-specific prevalence showed that PSC prevalence was significantly higher in ethnic European (14.35/100,000; 95% CI 11.11 –17.60/100,000) compared to non-European (5.45/100,000; 95% CI 1.41–9.48/100,000). The majority (66%) had a concurrent diagnosis of inflammatory bowel disease. Most (91%) had large duct PSC; 56% of cases had both intra- and extra-hepatic bile duct involvement at diagnosis, 33% intrahepatic duct involvement only and 2% extrahepatic duct involvement only. The median age of diagnosis was 52 years, and 60% were male.
Conclusion: Our population-based study showed that the incidence and prevalence of PSC in Canterbury were comparable to our previous reports, suggesting that the frequency and burden of PSC in Canterbury remained high. This study also demonstrated a significant difference in the prevalence of PSC among different ethnic groups living within the same geographical region, with the population of European descent having a significantly higher prevalence. It showed that ethnicity influences susceptibility to PSC and suggests a genetic predisposition to the development of the disease.
Poster presentation.